Copied from web archives of the old www.dairy01.co.uk web site. The creator of this web site James Aldridge -cheese making guru and master, has passed away but his memory lives. His website is no longer available but the information in it was regarded as one of the most reliable resource on cheesemaking.
Acidity Control (1)
The subject, which forms the basis of all cheesemaking, is extremely complex and you should accept these papers as a personal communication rather than as a definitive set of rules. They are a mixture of scientific facts, observations, examples, experience and a few opinions. They are intended to help shed some light on the way your cheese works and the ways in which you control it. Many of the following statements and descriptions of final results are conditional since: any reading of titratable-acidity can only carry a valid interpretation when related to a specific cheese, and the cheesemaker’s daily log.
At first sight it may seem that I advocate a scientific approach to cheesemaking, in fact, nothing could be further from the truth. The great cheeses of the world are the sum of the experience of not one but generations of cheesemakers. In today’s world this continuity of family pride, experience, and devotion to the traditional craft is not happening. Modern farming put paid to that.
So, what to do if we are not to loose these wonders of nature: cheeses whose flavours dance across the palette and are one of the joys of life?
Well, I hope to be able to help condense this experience by explaining much of what these people assimilated day by day. I certainly do not want to advocate the use of modern cheese-making short-cuts which exclude passion and dedication and place profit above quality.
My experience in the maturing and in the making of the many styles and varieties of cheese has taught me that, in traditional cheese-making, quality is inseparable from passion and that attention to detail is vital.
I have been described as "one of Britain’s finest cheesemakers" however: I regard myself more as a fault-finder rather than as a cheesemaker, which is why I have worked with so many types and styles of making. I have made a deliberate study of cheese faults and have looked for the cures in the hands of the producer rather than in the use of modern technological "cures".
My desire is to see the survival of natural cheese-making; preferably using raw milk and organic practices.
What I ask is that you take all the following as a whole. There are no "important" parts. From the moment you take control of your milk everything you do, every time you move your hand, has a real effect on everything that comes afterwards.
Here we go then:
Milk, Lactic acid producing bacteria, Rennet (or other coagulant) and Salt. That’s all we need…… Plus total dedication.
Oh, and one other thing…… you must be inquisitive.
Bacteria
From birth so to speak, take time to acclimatize themselves. If they then find themselves in a friendly environment they will reproduce and the numbers will increase rapidly. The numbers will reach a peak and then begin to decline. In cheesemaking this decline is the result of the bacteria themselves having used up all the available nutrients (there may be other reasons, which will be discussed). You, as the cheesemaker, will control the amount of nutrients available to your starter bacteria, and the suitability of the surroundings, and thus extend or limit their acid producing potential.
Lactose
Lactose is a disaccharide (two sugars) of glucose and galactose. It is dissolved throughout the milk fluid at a volume of around 5%. About 10% of the lactose is consumed during cheesemaking and the rest is lost into the whey. The lactose is the source of energy, in the form of carbohydrate, which is utilized by the lactic acid producing bacteria (starters). They consume lactose and exude lactic acid as a waste material. By the end of production most well made cheese will contain close to zero lactose. The starter bacteria will starve as a result and acid production will cease.
This activity also deprives many other bacteria of a source of energy, and this is one of natures "pathogen controls".
The acidity of the surroundings is all important in the world of bacteria and the absolute optimum acidity at which any given species of bacteria will operate at it’s best is within a very small range: one step either way will be the optimum for another organism which will use the same energy source, and may possibly produce substances which are harmful to the competition.
E.coli is a bacteria which will utilize lactose as their energy source but, they will only reproduce at an acidity which is low in comparison to that favoured by your starter bacteria. You will find that most pathogens favour lower acid (higher Ph) conditions. A good starter will generate acid at an even rate (not necessarily fast), thus never allowing the E.coli to feel comfortable enough to start reproducing before the acid levels become too high for it to function at-all or, all the lactose has been used up by your starter and E.coli starves. Nature’s pathogen control at work…….. Cheese, well made from good milk, will never present a risk to human health
The principal of acid "control" is the basic principal applied throughout your cheesemaking. You control good cheese by controlling the optimums.
The rate and extent of acid production exert control over every aspect of your cheesemaking. This includes the viability of the lipase working in flavour production and in body structure. A lipase is an enzyme, which causes the break down of lipids into fatty acids and the fatty acids are major precursors of flavour. Lipids are fats. Lysis is the breakdown of a component. Lipid breakdown is known as lipolysis.
Although you can’t see or measure the enzymes, you will find that the flavour profile of your cheese will change in relation to the rate and extent of your acid production, which controls the enzyme activity. When you change your acidity, or rates, (and throughout through your cheesemaking you do just this) you change the optimums for the bacteria and their enzymes. Of course, this means that you are responsible for the flavour.
It follows, naturally, that the flavour profile of cheese made from pasteurized milk can never be as complex as that of raw-milk cheese. The enzymes are produced inside of bacteria. Raw milk may contain many hundreds of species of beneficial bacteria, and the only bacteria in pasteurized milk are those which are introduced as starters, or from post-pasteurization contamination. Though the use of enzyme "soups" which are added during cheesemaking in an attempt to re-create flavours and to accelerate ripening is now widespread in commercial cheesemaking plants. "Accelase" is an example. The "ase" ending tells us t hat it is an enzyme and "accel" is self-explanatory.
I notice that many novice cheesemakers in the USA are using what they call "flavour enhancers" along with their starters. These are the enzyme additives I refer to and are totally foreign to real cheese-making.
With freshly drawn cows milk you will expect to register a titratable acidity (TA) of 0.15 to 0.17. (This is a pH of about 6.7). Incidentally, you cannot compare "acidity" to "pH". You may know some points that match here and there simply from experience though. As milk passes naturally to the calf it will become contaminated with viable lactic acid producing bacteria (streptococcus thermophilous etc.) which thrive on the milk residue in the mouth of the calf and in the teat canal of the cow/goat/ewe etc. During the milk’s passage through the stomachs of the calf these bacteria will begin to multiply – thanks to the availability of the milk lactose as an energy source and the close to optimum temperature for growth. Once in the abomasum (fourth stomach) the milk, now acidified, is ripe for the coagulating actions of the stomach enzymes, rennet.
So, we have a natural phenomenon: separation of solids from liquid: separated at a relatively low acidity by the effects of rennet and giving the calf a smooth, soft curd to digest (Cf. when a milk-fed baby burps up semi-solids). Without this "setting", the milk would pass through the animal’s intestine too quickly and be only partly digested. Had the acidity been higher (faster) this milk would still have coagulated but the resulting curd would have had a grainier and less cohesive body, relative to the acidity, and not have been in optimum condition for absorption.
Milk will coagulate simply from the affects of lactic acid, without the benefit of rennet at pH 4.6. This is what is known as the iso-electric point of casein. At 20°C this will take around 24 to 36 hours depending on the starter. Fresh cheese made purely through this lactic coagulation will have high acidity and a very fragile body comprised of fine flakes or grains with little cohesion. The particles will be very porous and hold lots of moisture. These “lactic” spoon able cheeses are usually sold either absolutely fresh or, packed in airtight containers and chilled.
The elasticity (cohesion) of the curd is dependent on the mineral calcium and this is "fractured" by acid and will then drain from the curd along with the whey. The greater the acidity at coagulation time the less calcium will have been retained and the less cohesive will the resultant curd would be. It will also retain more moisture since it becomes more porous with the loss of calcium. You might think of calcium as the natural "glue". How much "glue" you allow your curd to retain will depend on how firm or soft, or dry or wet, you want the mature cheese to be. Commercial producers will add extra calcium to the cheese milk as it means that they can work at faster and higher rates of acidity than is traditional. They will give you other reasons but the truth is that fast acid rates upset the calcium balance and this needs to be restored artificially.
The Artisan cheese-maker should beware of using commercial cheesemaking practices as criteria for their recipes. You do so only at the cost of complexity of flavour and personality. This will lead to a devaluation of your products as commercial plants continue to "improve" the flavour profiles of cheese made from pasteurized milk.
Lactic Cheese: is coagulated slowly, 24 to 36 hours, at high acidity and low temperature; it lacks calcium, has high moisture content, a loose and inelastic body, and a very short shelf life. It will desiccate very quickly if left exposed.
Renneted Cheese: coagulates quickly (20 minutes to 2 hours usually) at lower acidity and higher temperatures, it retains more calcium, has lower moisture content, an elastic body, is often pressed and has greater keeping qualities.
Where lactic coagulation & rennet coagulation meet is your cheese. You are constantly working with a balance within these two extremes.
If you make soft or pliable cheese types you will be attaining a fairly high acidity (low elasticity) but relatively slowly. If acid production is too high, or fast, you will make hard dry cheese lacking in flavour. If it is too low, or slow, you will make a sticky mess prone to gas formation, or, a hard wet cheese.
If you make a hard-pressed cheese you will be working towards a lower acidity (high elasticity) but faster. If it is too fast you will make a hard dry cheese lacking in flavour. If it is too slow you will make a soft bodied, poor flavoured cheese prone to gas formation.
Rennet: is a concentration of live chymosin and pepsin enzymes extracted from the dried vells (stomach membranes) of un-weaned ruminants. It will cause milk to coagulate quickly at, and below, pH 6.5 (TA ≈ 0.18). How; is another story.
Similar coagulation can be achieved by stimulating certain moulds or yeasts to produce large numbers of other enzymes which will coagulate milk, often known as "vegetarian rennet" (Modilase, Renilase etc.). There is now also the laboratory produced "Chymogen" which is a genetically engineered synthetic chymosin enzyme (the base DNA used in these genetically engineered coagulants is usually derived from E.coli or from the mold Aspergillus Niger, both of which can produce toxins). "Chymogen" is a trade name but other companies produce and market these genetically modified coagulants under similar names. The use of these is illegal in some countries, though (at the time of writing) they are used in around 80% of British cheesemaking. Personally, I find the use of genetically modified organisms in food to be quite frightening.
The coagulant you use will help determine the flavour, aroma and body structure of your cheese.
Cynara cardunculus
The plant "Cardoon" naturally produces an enzyme (Cardosine A) which will coagulate milk. This is a true vegetable coagulant and is used by most Artisan cheesemakers in Portugal. It is a member of the artichoke/thistle family. The flowers are plucked and dried then infused in warm water into a tea which is then used in the same way as one would use rennet: I usually use around 25 grams of dried flowers, twisted into a bag of cheesecloth, to a large cup-full of warm water to make up mine. I am not sure that it would be suitable for a cheddar-type cheese as it produces a more delicate set and, in my experience, seems to be rather more proteolytic than rennet. It has a quiet different life about it and it needs a perceptive person to work with it. {The amount you use will vary for many reasons… try 5 ml. of the mixture per litre of milk as a jumping in spot}. It grows fine in the U.K. and is perennial.
The coagulum of milk set mainly by the action of rennet (or other enzyme coagulants) will be so homogenous as to be jelly-like, since it will have set quite quickly at relatively high temperature: it will not be very acidic and will not have lost much calcium "glue". It will have shrunk slightly, and enclosed a lot of moisture within itself. That is, within it’s mass, not within the actual particles. All of the lactose will be accessible to the starter and the main acid production will start during coagulation. It is at this time that the acid producing starter bacteria are most active: it is warm and there is a high concentration of lactose available in the moisture to supply the energy to reproduce.
If we simply leave this coagulum undisturbed for some hours it will become very acidic.
If we cut or break the coagulum so as to cause it to loose moisture, and lactose, then the resulting curd will be less acidic in the same number of hours.
If we actually remove some of the moisture (whey) then the resulting curd will be even less acidic.
The amount of acid produced within the curd from now on, you control through temperature and the rate at which it is applied, the time that you allow the moisture to remain in the curd, your cutting, stirring, pitching, texturing, room temperature, milling, pressing, molding, type of mold, humidity, turning, salting. These are all acidity control points and will all influence body and flavour. If you make cheese already you are using these controls.
If you take 20 litres of milk, take it to 20°C/21°C centigrade, add 1% starter (this is about equivalent to what would be used in the average British hard cheese) and leave it undisturbed in an ambient temperature of 20°C /21°C, it will coagulate in 20 to 24 hours.
It will form a very delicate curd. If you handle it gently you can scoop the curd into a coarse muslin cloth which you should tie and hang to drain for a further 24 hours at 20°C /21°C, then hang in a fridge at 4c for 24 hrs to produce a wonderful Quark cheese. It is usually lightly whipped before serving or potting.
This is lactic cheese. In other words, the coagulation results purely from the effect of lactic acid and is rennet-free.
If you add just one drop of rennet to the milk you are taking the first step towards rennet cheese: the curd will set sooner and will be more cohesive, and will be closer to the modern Fromage Frais. One more drop and the curd will be stiffer and more suitable for cheesecakes etc. There’s a limit of course.
The acidity must still be allowed to rise for the full term before the curd is disturbed. The more acid the curd the deeper will be the surface layer of free whey, and the more likely you are to observe cracks in the curd surface.
You will probably find that when the ideal acidity is attained you will see that the curd is just beginning to shrink away from the sides of the vessel, and there are perhaps just one or two small cracks in the curd surface.
The acidity at which you disturb this curd is extremely important to the quality.
You should take a reading of the whey acidity before you disturb the curd, then when you make a first rate cheese curd (not too acidic and fragile, and not under acid and stodgy) you will have a guide for every make. In fact, you will have a recipe and in future you will ladle/cut according to acidity and use time merely as a guideline.
You may increase or decrease the acidity simply by extending or decreasing the time, or by increasing or decreasing the amount of starter. Temperature changes will affect acidity rates but will also affect the curd shrinkage and body.
The most common causes of failure are poor temperature control and poor starter management.
The whey in which your cut curd is floating contains lactose; if you reduce the lactose available to the bacteria within the curd then you reduce their life span and acid producing ability.
The point at which you remove the whey is a major acidity control. The sooner you remove it the slower will be the rate of acid production during the rest of the make. The smaller you cut or break the curd the slower will be the rate of acid production. This applies whatever cheese type you are making. If we were to cut our curd into 1-inch cubes each cube would have 6 square inches of surface area from which to loose moisture. If we cut these cubes in half we will now have 8 square inches of surface area, and so on.
As the available lactose decreases the bacteria recognise this and will reproduce ever more slowly to avoid over- producing competition for the failing nutrients.
The curd shrinks and looses moisture through the influence of heat, acid, and of rennet: and through physical pressure (stirring etc.). With any cheese, the way in which you handle the curd throughout cheesemaking will influence the acidity of that days make. The more roughly, or firmly, you handle your curd the faster it will loose moisture (containing lactose), and therefore will have a lower potential to produce acid. The more you leave it undisturbed and the more gently you handle it the more it will acidify. The French have a wise old saying that it should be handled "like a bride".
Pressure at any stage before salting will influence acidity. In fact, any physical action which assists drainage will reduce the acidity potential by reducing the amount of moisture in the curd and, along with it, the lactose which is the energy source for the remaining starter organisms.
With experience, you will eventually be able to quite easily "read" the acidity of the day’s curd simply by the feel of it related to time. The more fragile the more acidic. The more stodgy the lower the acidity….as a basic. Don’t kid yourself too soon though.
As you will see, what you do at any given point usually has no immediately apparent influence on your cheese: it all takes time. This is where your acidity readings and log becomes your back door into what is going on in there. Once you know what the acidity should be at certain stages then, in the midst of a make, you will be able to decide whether or not you need to increase or decrease the rate from then on in order to maintain the right balance for your cheese.
How do you find out what the acidity should be at these "stages”?
Well, first off, you make a cheese, whilst being guided by a recipe from whatever source that is somewhere in your mind around what you would like to make.
You will see cheese grow in your hands. Study what is happening, study your curd, take acidity readings and you will begin to recognise "high" and "low", "fast" and "slow", "wet" and "dry". If you can follow a cheese throughout its life you will begin to assimilate all, from the milk to the end effect.
Don’t worry too much about mistakes, there is no such thing. It is all learning, and every mistake adds to your experience.
When, one day you make a "great" cheese, you will know how you did it, and you will keep that basic record come hell or high water. When your readings wander from the norm, and what you make is not great or it just doesn’t feel right today, ask yourself why? Compare the logs and see what is different. Listen to what your cheese is telling you, feel it, talk to it, and assimilate everything you can from it at every stage. Cheesemaking is not something you can do now and then… you must live with it! Then you must learn how the seasonal deviations in milk and weather will call for changes in your making.
If you have come this far then you realize that you have not set yourself an easy task. The rewards though, of working with nature, are overwhelming.
Try not to make more than one change at a time to your recipe.
You have a limitless number of possible combinations to work with but one group will apply uniquely to your cheese, and you will get to know them much sooner simply by listening to what your log has to say. The variations can often produce favourable end results but, if you have no record of what you did it can take years before you are able to repeat it, and it is so easy to get lost by wandering further and further in the wrong direction.
You probably won’t see the end results of your actions for some weeks or months even, and it is extremely unlikely that you will remember every one of your actions over this period. You must keep an honest Log!
You should be aiming always for that "golden" cheese, and a good cheese-maker is able to control the make to such an extent that any deviation is minimal. This is not standardization; this is simply good cheesemaking practice.
All this may seem rather nebulous to some of you but, we’ll get there.
Acidity Control (2)
Enzymes are catalysts; they initiate innumerable reactions in your milk and in your cheese. Distinct enzymes tend to initiate definite reactions. Lipase, as we have seen, causes the breakdown of fats.
Protease causes the breakdown of protein. This is proteolysis (protein – protease – lysis – proteolysis).
Casein is the major protein found in milk or cheese, and this forms the greatest bulk of the cheese body.
Lactase causes the breakdown of lactose and also contributes to flavour and aroma.
Enzymes are vital to the body and flavour changes in the milk and in the ripening or maturing cheese. They are produced inside of bacteria and, whilst some are released when a bacterium is still functioning, most are released on its death, throughout cheese-making and maturing.
Bacterial, and therefore Enzyme, actions, or non-action, are controlled by acidity, temperature and available moisture.
It’s the enzymes that cause the breakdown of a "wet acid" cheese like Camembert into a soft, putrefying mess within two to three months. It’s the enzymes that cause the transformation of a lumpy, low acid, curd into smooth "dry" Cheddar in nine months. It’s the enzymes that help produce good flavours and to produce poor flavours.
So, although the milk will supply the initial ingredients for flavour, it is you the cheese-maker that will control the actual flora and flavour production. Not that you will do this consciously at first.
The controls for enzyme action in maturing cheese are temperature and moisture.
The higher the humidity of your maturing room the more moisture will be retained by your cheese. The more moisture retained by your cheese the more rapid will be the breakdown. The higher the temperature the faster the breakdown. The lower the cheese acidity the faster the breakdown. (This has to be qualified, later).
Fast breakdown may be desirable in some cheese and these are stored at high humidity in order to retain the moisture content throughout maturing. Other, dry-rind, cheese would be kept at a relatively lower humidity so as to discourage surface breakdown due to mold, bacterial and enzyme action, and to ensure that flavour reactions take place at a rate suitable for that cheese. The bandage on traditional Cheddar is part of a carefully controlled moisture loss system.
I use the word "traditional" in its true sense, not, as it is used nowadays, to elevate the marketing image of a factory cylindrical cheese above that of a factory block cheese.
Acidity Control (3)
The Makings – Milk, Starter, Rennet, Salt
Milk: Poor milk will make poor cheese; however, good milk will not necessarily make good cheese. It is the diligent cheese-maker who makes good cheese.
Good milk is that which is hygienically drawn from healthy animals.
Every pasture will present a different array of vitamins, minerals, proteins, fats, acids, bacteria and enzymes.
The more natural the pasture the more diverse the basic ingredients which the cheese-maker has to work with.
Consequently, the more complex are the flavour and aroma compounds available to the cheese-maker.
Every animal will add its own system to the chain and produce milk that is distinct from another’s. The possible variations are limitless but will produce a unique consistency throughout a herd or flock.
Sheep’s milk will contain between 60% and 100% higher total solids than will cows milk
Goat’s milk will generally contain 1 or 2 percent lower total solids than cow’s milk.
Therefore, a recipe designed for cows milk cheese will need to be quite drastically re-vamped in order to produce a similar cheese using either sheep or goat’s milk.
Starter: There are many possible natural variations of bacterial mixes. The bacteria naturally occurring in the milk from one area, or farm, are likely to be quite distinct from those found in milk from another site. If you were to rely purely on these bacteria then you would be rather more restricted in what type of cheese you could produce. There are many species and sub-species of lactic acid producing bacteria and some will have very distinct optimums for growth. Some of these will produce other things aside from lactic acid. They will produce other acids, at various rates, gases (useful for Emmental, Gouda, Blues etc.) and, different enzymes – which all serves to create distinct reactions in the cheese-making and cheese ripening. You also need to consider the temperature range of your cheese-making – for example – the Gruyere, Emmental and Italian types are taken to high temperatures during the making (Gruyere will be taken to around 55°C) and this calls for the use of a "thermophilic" (high temperature) starter, whereas the majority of cheese-making uses "mesophilic" (lower temperature) starters, these will be damaged or killed at temperatures above 40°C.
Whatever system of starter you may use the even distribution of the organisms throughout the milk is vital to good cheese-making. In other words, don’t skimp on the stirring when adding starter.
If you were to propagate the lactic acid producing bacteria naturally occurring in your own milk you would have a starter which was unique. If you use a frozen or freeze-dried starter then this may be either propagated or, inoculated directly into your milk. It makes no difference to the quality of your cheese whether you propagate this daily or use it for direct inoculation, provided you stick to one method. However; a propagated starter will be already active, and we shall see as we progress how this will affect the cheese-making recipe.
If you are not intending to produce your own natural starter then you need to take advice on which commercial mix to use. This will depend on the style of cheese that you hope to make.
If you take pot luck with your neighbour’s starter you will be restricted within a range of styles. This doesn’t mean you can’t make a cheese that is very different to your neighbour’s, simply that there will be cheeses that you can’t make.
In Britain it is still possible to buy what are known as "frozen pints"; these should be historical mixes which originated on the farm and have been propagated and maintained as pure for many years; however, these mixes were developed only as a basis for hard Cheddar-type cheeses and would be quite unsuitable in many other styles of cheese-making which are now practised by our Artisan cheese-makers. Just as the Dutch Gouda equivalent or the Swiss Gruyere would be unsuitable for Cheddar making.
Whatever type or method of starter addition you employ you must treat your starters with as much respect as you should the rest of your cheese-making….. I mean absolutely must! So many silly problems stem from starter ill-treatment.
I have a French cheese-maker friend who does produce his own, natural starter, as do many European cheese-makers (though I know of none in the U.K. who do so except on the odd experimental basis).
This calls for the hand milking of a prime animal, which has not been treated with any anti-bacterial teat applications, and allowing the milk to acidify naturally from the effects of the endemic teat bacteria. After splitting and propagating this milk for the first few days in order to detect any obvious problems, one uses a percentage of it to produce the required acidity in the required time in a specific amount of milk (easy aye?). This can then be used to start the cheese-making, whilst the required amount is propagated in more milk for the next day, and so on. (A common-sense follow-up would be to have the early "starter" tested for possible contaminants).
Another method is to allow the evening milk to acidify naturally and mix it with the fresh morning milk. It requires a cheese-maker of great experience to make cheese in this fashion, and even then will produce extremely variable cheese, requiring intensive care in the maturing room.
Another method is to "start" your milk with a specific amount of live whey from the previous day’s make. This method is usually only employed where the cheese-making involves overnight coagulation and fresh whey is directly available to inoculate the fresh new milk, as with much Goat cheese-making.
"Natural" starter production is a practice that is frowned upon nowadays since during propagation the milk is highly susceptible to contamination. These starters will gradually become less active and knowing when to change them is almost pure art. Natural propagation should only be employed by a very experienced producer. Animal health, milk and hygiene have to be immaculate and it would be most unsound to even consider producing a starter from bought in milk. Experience is the main factor – and this doesn’t come without a price.
If you intend to make cheese commercially on even a small-scale basis then it is unrealistic to consider producing your own starter. Unless you have two or three generations of experience to call upon in your cheese-making.
Changing from your own, natural, starter to a commercial one would change the characteristics of your cheese and would necessitate changes in the recipe, which would still result in a noticeably different cheese.
It is for this reason that many small-scale makers in Europe have the benefit of derogations under E.C law, from the T.b.c standards for raw milk for cheese-making. (In Britain our own Ministry of Agriculture decided that the small-scale makers should not be granted these derogations, which, effectively, makes it illegal in Britain to produce many of the traditional Goat-milk cheese styles). ( fu )
The D.V.I. starters (direct vat inoculation) are pretty consistent, and variations are minimal.
If you don’t use a whole sachet the rest must be stored in an airtight container and kept dry, cold and dark, or discarded; folded over is not good.
The average Dairy microbiologist will tell you that you should never split sachets but discard any unused culture. This is purely academic hygiene since, for your culture to become contaminated in the dairy, conditions would need to be such that your milk would be already contaminated. The least intrusion of moisture from the atmosphere will weaken the culture (it will get lumpy) and in this case it should indeed be discarded. Ultra-violet light will kill bacteria in seconds, so sunlight and fly-zappers are particularly to be avoided. This applies to rennet as well. Phenolphalien, which you use with your acidometer, is also affected by light. You should store it cool and dark.
Wearing my "purist" hat I would like to see more use of natural starters; however, my realist’s hat tells me that this is not a something which I should encourage. The reasons for this are numerous, and are based neither on legislative nor on hygiene considerations. Someday I may get around to explaining the reasoning on paper but, as I said, it is extremely complex and involves every aspect of cheese-making from pasture to maturing.
Rennet: We have pretty well covered, unless anyone is considering treating their own vells. The effects of rennet will be discussed later. The amount of rennet you use will affect the final cheese so this will depend on the type, or style of cheese you intend to produce. You must measure the quantity accurately for each make.
Salt: Salt restricts bacterial growth. For the starter bacterium to obtain lactose it must absorb it through its cell wall. If you could block its pores it would starve to death. This is more or less what salt does.
Different bacteria have different tolerances to salt. Starter bacteria are (in general) restricted by around 5% salt. That is salt percentage in moisture, not in the whole cheese (this would be around 2% in a 40% moisture cheese).
Salting too soon can produce a low acid cheese and leave residual lactose available as an energy source to many undesirable organisms.
In British territorial cheese-making (Cheddar, Cheshire etc.) the salting stage is reached in just a few hours, and salt is deliberately used as a bacterial control. Fast acid production is employed and the lactose level is further reduced by cooking, stacking, cheddaring, salting, and milling the curd and then subjecting it to high pressure. Stilton is the exception and still retains ties to its French origins, as did Wensleydale cheese until the early years of this century when the process became heavily mechanized and the recipe was bastardized.
In most cheese-making styles salt is applied much later, usually from 1 to 3 days after moulding, and the salt is applied either on the outside of the fresh cheese or by immersion in a salt (brine) bath. In such cases the cheese-maker relies on control of the starter bacteria for the job of lactose removal since these types are rarely heavily pressed, and many are not pressed at all.
Camembert cheese is not pressed at. Stilton is not pressed. Parmesan is very lightly pressed for about an hour, if at all. Manchego is lightly pressed by stacking one mold on top of the other and inverting them frequently. MostTomme type cheese is pressed simply by hand pressure, or a weight of less than the cheese.(In all cases we are talking of traditionally made cheese).
Remember, the starter bacteria are still functioning since these cheeses have yet to be salted so, pressure, or the lack of it, is an important part of the acidity control.
Acidity Control (4)
You should use an acidometer and learn to understand the implications of the readings.
Once you do this then you will know how to steer your cheese in the right direction or at least, away from something that is obviously not what you want.
You can compensate for hic-cups, and make minor changes, if you understand what effect they are likely to have on the following stages.
Even if you don’t understand technically you should soon begin to associate fluctuations in the log with fluctuations in your cheese.
Acidometers are very simple to use and will cost you around 60 pounds sterling If you don’t use an acidometer it will take many years of trial and error before you are confident that your cheese is good, and fairly consistently so.
During this time you are assimilating masses of information and learning to interpret them through personal feelings of touch and smell and the look of things. This learning is a great experience. Full of frustrations of course – and lots of pretty dismal cheese.
If you start with a little more information many of the frustrations are minimized, and the dismal cheese periods are reduced.
If you are making cheese for the right reasons you will eventually get there anyway but this will take you many years, and every hic-cup is a costly headache and a waste of good milk.
I have known many cheese-makers who did not, and do not, use an acidometer. Some of these have long term experience and make cheeses that have earned their place in history.
When these same people had little experience and were making cheese of variable quality the market was tiny, or local. Most of you now are aiming at a wider market, which means that the majority of your cheese will be handled by people with little experience, and a greater consistency in the quality of your cheese-making is required. Sooner.
You should keep a fairly detailed log when learning, or developing a new cheese. (If you don’t have a record of what you did last month, and you have gone down the wrong road, you will get lost trying to get back).
Once you are happy with your cheese the log becomes a very brief record. Ideally, you should learn the basics by working alongside an experienced cheese-maker. The more you can work with the more you will be influenced by the diversity of styles.
A log is a simple affair. It is a record of time, temperatures and acidities (and a few cryptic notes). Not complicated, and not a bother at all. Particularly if you are making just one variety and use a large diary as a log. You must be able to easily compare today’s make with the previous ones.
The layout of your log is up to you. You need to record temperatures and acidities related to time. You can buy printed log sheets for the standard British cheese varieties, but the layout of these is not suitable for the majority of Artisan makers. You can easily design one that suits you though.
Something on the lines of the one below can be used for any type of cheese.
You will need a clock. Preferably one that is easy to reset, as it is much easier to compare one make with another if you time each make from zero, or 12 o’clock.
Acidity Control (5)
I think the best way to continue is for us to run through a simple recipe.
I must first assume that the milk is of good quality and that you are using good (realistic) hygiene practice.
Without good hygiene you will not make good cheese. We will discuss hygiene elsewhere but for the moment we must assume that you already have an understanding of the subject.
Ready ?…. O.K.
We will take 100 litres of milk. Let’s make it sheep’s milk as we can then include some discussion of the differences you will encounter with milk from other species.
(Sheep’s milk contains almost twice the total solids of cow’s milk. Goat’s milk will generally contain a little less total solids than will cow’s milk. As acidity is read as a percentage in moisture the differences in solid content will affect the reading of fresh milk, not the actual Ph. though.).
We will take this milk to 28 degrees centigrade. If we were using cow’s milk this temperature would probably need to be around 30c, you may have worked out why already.
We want the milk temperature to stabilize at 28c, and to achieve this we will need to cut off the heat supply a few degrees before that. Just when you cut the heat will depend on your heating system. You will generally find that you need to cut it at 2 to 3 degrees below the desired temperature and then wait for it to stabilize. The faster you heat the sooner you will need to shut it off.
Starter addition is next. We are going to use a medium to slow mesophilic D.V.I (Direct Vat Inoculation) starter. We will use 8 ml. per 100 litres of milk. We need 8 ml. today then. Do this right. If you change it you make a different cheese: maybe something nice or maybe not. Either way, your cheese will change because you tell it too.
I find that the easiest way to measure D.V.I starter is to use a set of small kitchen spoons. (Buy a set for a few pence from any kitchenware shop). These will measure in millilitres but, the object is to find a way to add a measurable amount of starter, and this is an easy method when using small amounts
The reaction from a starter is never going to be precisely the same in each make but your cheesemaking will fix this.
Sprinkle the powder over the surface of the milk and stir well in for a few minutes. There must be no sign of any grains when you are done.
Cover the vat, bucket or pan and leave it for 1 hour. Give it a stir occasionally when you are passing.
Providing you have the room at around 20c there will be little or no heat loss.
You now need to take a TA (reading of titratable acidity). You should have a fairly high reading of around 0.26 as it is ewes milk (the acid/whey concentration is higher because of the higher solids). If you do not then you have a problem; either your milk is contaminated or you have mishandled the starter or you did not attain the desired temperature.
Rennet addition: We will use 20 ml. per 100 litres. This is around average for a British style cheese. The rennet needs to be mixed in about six to ten times its own volume of sterile cold/tepid water. This will help to distribute it evenly throughout the milk.
Stir it thoroughly into the milk for about 2 minutes (with cows or goat’s milk you may stir for a little longer, though if you are working with small quantities 2 minutes is sufficient). Do not stir for to long but make sure that you stir upwards from the bottom to ensure a good distribution. If you continue to stir once the rennet takes its first bite you will ruin your cheese irretrievably.
Cover the vat again and leave for around 27 minutes. You must not disturb the forming curd in any way during this period. If you uncover the vat do so very gently as any vibration will shatter the curd and cause it to release moisture which will result in a slower acid production, and you will then have a different curd to deal with throughout the rest of the make.
(If you were using cow’s milk it would take at least another 30 minutes before the curd was ready to cut. Not that a cows milk cheese can’t be made using the same style of cheesemaking).
What we now have is a nicely acidifying curd that presents an environment that is unsuitable for the growth of pathogens. It will have lost some calcium and the minute particles will have become absorbent and will retain moisture throughout the making and maturing.
If you were to use more starter the acid production would be faster and the particles would retain too much moisture. This will lead to a cheese that will leak moisture at the beginning of the maturing period. It will then gradually become hard and grainy as it ages. A very similar end result can result from the use of too little starter also, as we will see.
You now need to check if the curd is ready for cutting. To do this you should push your dairy thermometer; finger or a small rod a few inches down into the curd and lift it gently up and away from you. When the curd is ready for cutting it should break evenly across the rod. If it breaks unevenly and sticks to the rod it is too soon to cut and you must try again in a few minutes. Do not leave it longer than is necessary or the resulting curd mass (not the particles) will retain too much moisture and the cheese will be sour.
The smaller you cut the less will be the acid production in the later stages. The type of knives you use are usually an important consideration, but in this case we are going to cut very small so almost any style of knife will be ok.
You must be very gentle with the curd from now on. Cut as gently and as evenly as possible. Ideally you want a series of vertical cuts followed by horizontal cuts and keep repeating this procedure. This will depend entirely on what type of knife is available to you but aim gently towards a uniformity of curd piece size.
Take your time and get the curd pieces down to about 3/8 of an inch cubes (1 cm) in 20/25 minutes. Now take 5 to 10 minutes and clean and sanitize your knives, and your hands and arms. Now stir the curd, preferably by hand. Start gently from the top and gradually work your way down to the vat bottom without crushing the curd, then stir for a few minutes until the pieces are all separated and floating freely.
Now apply just a little heat (you are looking to raise the temperature to just 30c in 20 minutes) continue a cutting and stirring motion with your vertical knife. The curd should still be quite tender an easy to cut. You must keep an eye on the temperature during this period and, soon after it starts to rise turn off the heat. You do not want it to continue rising and go above 30c. or you will make a chalky cheese. Keep up a gentle cutting and stirring action until the pieces resemble peas and rice (perhaps another 20 minutes). Stir to float the curd and then allow it to settle. (Apart from the cutting, the curd pieces will be reduced in size by the shrinking effect of heat).
Now, leave it to rest (pitch) until 2 hrs and 35 minutes have elapsed since you put in the starter. {start time}.
Then stir for a few minutes to float the curd again. Now take another T.A. It should be around 0.17. This appears to be lower than when renneted. (Don’t worry about that for the moment, as I shall explain it later in the pages). Record it though.
Cover the vat again and leave (pitch) until it is 3 hours from start time. Take a T.A. This should now be at 0.22 to 0.25.
You have almost finished the actual make now. Give it a good stir to separate the curd pieces. It should still be easy to crush the curd pieces at this stage.
You now need to remove most of the whey from the vat. {Not all, as you would in cheddar making.}
An easy way to do this is to put a sanitized basket of some sort into the vat (perhaps a plastic colander) and scoop the whey off, from within the basket, with a small bowl. From 1 hundred litres of ewe’s milk you get very little whey and it takes maybe five minutes to take off the desired amount.
Stop when you have the level of whey just below the settled curd level.
It is now time to fill the molds.
There is a picture on the previous page of the type of mold that I use (plenty of drainage holes) so try to get hold of something similar. If you can get some that are just slightly tapered all the better as you can stack them 2 to 4 high rather than use weights. You don’t have to use cloths in the molds since these are virtually "basket mold" cheese, but if it suits you to use cloths it is better not to do so until after the first turn. (I simply place a cloth under the follower when the weight is applied).
After the first turn you will need to place a follower on the cheese unless you are using tapered molds.
Fill the molds to the top as quickly as possible without rushing, and as soon as you have them all filled start with the first one and invert it onto a table. The cheese will drop out in one piece (if it tends to break up at all you probably took the temperature up too high in the vat and dried the curd out too much). Pick up the cheese gently, holding only the sides and drop it back into the mold.
When you have them all turned place your follower on the cheese and then an 8 to 10 Kilo weight
(a clean plastic bottle filled with water? 1 litre weighs 1 kilo). Repeat this procedure after about 20 minutes, then 15 mins, then after 30 mins and again at gradually longer intervals for about 5 hours. The trick is to get both ends uniformly smooth.
You should watch the rate of whey expulsion from the molded cheese and when it is barely perceptible take an acidity reading from it (take lots of them at different stages at first, watch them increase and record them. This will teach you how to recognize the rate of increase). This should be done at the same time, from start, on each make. Be sure to use fresh whey. (I use the first molded cheese on a separate draining tray, to catch the whey from for reading). These reading are important clues to the consistency of the quality of your cheesemaking and will assist you in making variations to the recipe in future.
Remove the weight as late as possible and leave the cheese in the mold overnight with the least smooth side down. Room temperature should not drop below 18/21c during this time.
Turn in the molds as early as possible next morning.
At around 22 to 30 hours from starter (this will have to simply be juggled to fit in your day) place the cheese in a 20% brine solution. You need to sprinkle the top of the floating cheese liberally with salt or the upper surface will retain too much moisture, which will cause this side of the cheese to soften during maturing due to excess enzyme action.
The 2 kilo cheese will need to stay in the brine for about 19 to 24 hours. A larger or denser cheese would need relatively longer, and vice versa. A small, fresh goat cheese style would brine-salt in 1 minute.
On removal from the brine bath the cheese should be placed on a clean wood board, which is set at a slight angle to assist drainage, and turned onto a fresh, dry board, every few hours for the next two days, The humidity of the room should be in the region of 75% Rh (relative humidity) this may call for the use of a fan or dehumidifier at times.
Once the cheese surface is fairly dry to the touch then the cheese should be taken to the maturing room (at a Rh of around 86%) and turned daily for the first ten days. After this it should be turned regularly to ensure an even moisture balance throughout the cheese for the rest of the maturing period (10 to 20 weeks at 15c/58f).
This will be your interpretation of the cheese below. But what you make will be your cheese and in subsequent makes you will refine your making and stamp your soul on it. This is where your understanding will come into play; you know you can communicate with your milk and with the curd. Think about what your hands are doing, store every feeling, record as much as possible, and ask yourself …….WHY?
The answers are in your log. When the cheese is different next time, and you are keeping an honest log, it will show in the entries. Just try a rise of 2c in your heating and see the difference (you will need a good deal more weight when pressing though). Try reducing the milk ripening time and you will have a different cheese again. Stir for longer and pitch for less time, and you will have another cheese. Cut the curd larger… another cheese.
Every time you move your finger you are affecting it as only you will ever be able to. It’s your cheese. Only total dedication will make it consistently good.
In fact I filched the recipe style from a Westmoreland farmer and it is very much a "Northern" cheese.
100 litres of ewe’s milk will make up to 22 kilo / 48 LB of mature cheese.
Well cared for, the cheese should be best at about four months +, but is also nice as a young fresh cheese.
Matured, it should have a thin sturdy rind and a very slightly open texture barely tending towards flakiness. The body should be firm yet smooth and light after the onset of homogenization, or enzymatic breakdown, at about three months. It should not show any signs of distinct breakdown under the rind.
After a month or so in the maturing room the cheese will have formed a fairly firm mould-covered rind. If this mould growth is allowed to proliferate uncontrolled it will cause the rind to soften. (The mould will reduce the acidity of the rind and this will then lead to excessive enzyme action). To prevent this you must at first rub the rind vigorously by hand now and then to restrict the moulds and, as the cheese ages, gradually progress towards an occasional vigorous brushing with a stiff bristled brush.
Matured Cheese
Although it will be a good keeping cheese it should always be light and quite moist nonetheless. It is just a simple cheese, yet the making embodies the basis of all cheese- making.
This recipe, with very little variation, also makes an excellent Blue cheese. You will simply need to include a little "penicillium roqueforti" with the starter, do not cut so small in the later stages, press very lightly, pierce the cheese at around 3 weeks and do not allow the humidity to drop below 90% in the maturing room until the cheese is at least 8 weeks old. You may need to run a hot knife over the cheese on the second or third day in order to smooth the surface. You are aiming for a Stilton-like rind finish eventually or, if you film-wrap it, pierce it at around 4 weeks, still in the film, and store it at 4c for 4 months you will have a very different but equally nice cheese.
Notes: This recipe is kept simple for those of you who have no mechanical press. If you do have pressing facilities then applying a few basic changes will give you a smoother, lower acid, cheese (does not apply to Blue cheese).
Do not cut the curd quite as small: reduce the pitching time and increase the stirring times: and increase the scald temperature by 2 to 3 degrees (ideally at a rate of about 1c per 10 mins). You will need to apply just a little pressure initially and use cloths in the mold after the first turn, when you can then increase the pressure progressively.
Your log will, of course, look quite different and you should by now be able to work out how these actions affect the acidity readings and the body and texture of the cheese.
Remember: personal attention to detail (smell, feel, taste and look of the curd) in each make is vital if you are going to make a consistently good cheese. Your readings are just a powerful tool in learning how to talk to your cheese.
If you use the fresh whey from this make (it will become too acidic if left for long), and you have the facilities, you may like to take the whey temperature up to around 90c (just below boiling), turn off the heat and then leave for about 40 mins. You will see that the remaining protein will flocculate and float to the surface. Scoop this off into a basket with a fine strainer and allow it to cool and set. You now have the finest ricotta. You need to use a Bain-Marie style of heating… not direct heat. When I make for the family I use a stainless bucket inside a larger one part filled with water, and heat on a gas ring.
Brine Baths
The older cheesemakers will tell you that you should not renew your brine but simply add more salt as required, and they have very sound reasons for this.
However; in today’s climate of hygiene hysteria it is advisable to change your brine solution periodically.
When you first make up a fresh solution the pH of this will be around pH. 7.00. (Neutral).
Now, the average pH of any cheese, which you are going to float in this solution, will be around pH 5.00. When you use this new bath the pH of the brine will try to level out and this will increase the pH (in other words, reduce the acidity) of your cheese. This will lead to many possible defects:
Usually they will manifest themselves most visibly in rind defects. You will feel a greasiness of the rind at first.
This will develop into areas of sticky and discoloured patches, with the discolouration varying from straw colour to bright orange, red or brown. The surface will be prone to show growths of the black or grey mucor molds (poille de chat). The body of the cheese will be weaker and softer than desired. The low acidity will favour the growth of spoilage organisms, flavour will suffer and the keeping quality of the cheese will be reduced considerably.
No problem:… there is an answer to this. As any Dutch Gouda maker can tell you. You simply add acid to the fresh solution and from there on both the brine and the cheese are happy. This can be done with lactic acid but the cost is a little high. I use the same acid as the cow does in it’s digestive system: hydrochloric acid (which you can buy from a chemists / local pharmacy).
Right, let’s make up a brine bath.
You need a 20% solution. We will work with 100 litres, just to make things easy, but you will make up what is required for the amount of cheese you usually make per batch.
1 litre of water weighs 1 kilo. 100 litres of water: 100 kilo. So, for a 20% solution you will need 20 Kilo of salt. (If you work in pounds and ounces: a Gallon weighs around 10 lb.). I usually find that I need one for the pot as well. Particularly if one uses sea salt as this is not so purified.
Dissolve the salt in the water. It will take some time so leave it to soak before you really do a lot of stirring.
Once it is dissolved you need to measure both the salt solution and the pH. A very fresh egg will float in a 20% solution and this is a very reliable method in home-production but what you really need is a Brine weight. You simply float the weight and read the percentage that is marked in gradients on the side. Then add either more salt or more water as may be necessary.
The pH can be measured with a pH Meter, expensive and unreliable for the small producer.
What you need is a pack of pH Dip papers (litmus paper). You simply dip one of these strips into the solution and then read the pH off against the colour chart on the packet.
The reading is going to be far too high, so now reduce it.
Put a couple of litres of water in a jug and add the equivalent of 3 or 4 teaspoons of the acid to it. If you are using Lactic acid you will need a good deal more. Pour about half of this into the bath and stir for a few minutes. Then take another Ph. reading.
Continue to add until you have a pH of 5.00.
You should be using the solution at a minimum of 15C (60 Fahrenheit) and maximum of 20c. 18c is the norm. Below this temperature the salt will not be properly absorbed and, the low temperature will restrict or kill many of the flavour producing organisms in your cheese. Store it at room temperature and keep it covered and clear of any cheese particles and it will be fine for the whole season.
Done.
When you use this bath the cheese will absorb salt and reduce the solution %. Every time you put fresh cheese into the solution you must give them a liberal sprinkling of salt to compensate for this. The cheese should be flipped over in the brine halfway through the brining period and sprinkled again with salt or you will find that the upper side of the cheese will soften as it ages because it will retain more moisture. Measure the salt solution % occasionally by all means, but once you have a little experience this will only be necessary about once a month.
I keep a very fine mesh gadget to hand (a plastic swimming pool skimmer) and skim the surface of the brine shortly after each use. This removes any cheese particles and helps to keep the solution clear.
Periodically you need to filter the solution thoroughly. I do this by either pumping or bucketing it from one container to another and back again.
You can make up a simple yet effective filter by lining a basket or colander with cheese muslin and passing the solution through this. This gives you the opportunity to clean the bath and surrounding area. Do not allow a smear of slime to develop on the sides of the bath above the water line… this will be fat and bacterial growth.
A note on pH. If you do not set the pH. of your brine solution it will gradually level itself out as it takes acid from your cheese so, after a period of time the pH will be correct. However, this will depend on how often you use it and how much cheese you float in it so it will take some time and in the meantime you will be reducing the acidity of your cheese. This is why the older cheese-makers did not change their solution…. in most cases, for many, many years.
