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GENERAL CHEESE MAKING BOARDS (Specific Cheese Making in Boards above) => STANDARD METHODS - Making Cheese, Everything Except Coagulation => Topic started by: Alpkäserei on October 27, 2012, 06:11:09 PM
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There is an oft-repeated misconception that we have no way of judging the acidity or workings of the culture without using some means of measuring the acidity.
This of course, is a myth.
Traditional cheesemakers have made the world's finest cheeses for hundreds of years without ever once measuring the pH. While the technology has been around for centuries, it still has not yet found its way into many old world cheeses.
Throughout the process of making cheese, there are a wide number of subtle indicators that tell us how the cheese is acidifying. There are certain things that happen in the cheese that an experienced observer can use to time important parts of the cheesemaking process. A little bit of the technical side of cheesemaking can be put away in exchange for a lot of art.
The number one most important measure we have of the acidity of the cheese is the character if the whey. I was taught by a fine old Swiss Cheesemaker that you proceed to cut the curd not when the whey has reached a certain pH, but once it has become 'schon gälb' (pretty yellow). In other words, I was taught to watch the whey until it took on a precise nature of color and clarity. Then it was time for the next step. I am doubtful that he had any knowledge that it was really the acidity that we were looking out for.
If you observe the whey during the process of the make, you will notice changes occurring throughout the process. When you first cut the curd (VERY slowly, mind you) then it should be a milky white, almost like skim milk, maybe with a slight yellowish tint (if it is right away yellow, then your are too acidic). Here is where the speed of cutting is important. If you stir too fast, you disturb the whey and mess up the acidification.
When making Alpkäse, the curd is first cut to great big coarse pieces and then stirred for about ten minutes. In this time period, the whey changes color. Once it is 'Schon Gälb' then it is time to cut it to final size. Same thing when brewing the curd, once it has deepened to the proper shade of green we know the cheese is at the right stage in its development to start cooking the curd.
What is occurring here is simple, the whey when we first cut it has a lot of proteins and sugars suspended in it, but not very much acid. As the process continues, the acid reacts with the solids still in the whey to turn it first yellow and eventually to a pale green. This is caused both by acid developing in the whey itself and by acid being dispelled from the curd. This is why we don't ever work too fast, if you stir the curd too roughly, you cause it to loose too much acid which makes it difficult to judge the whey. The acid is produced by the culture, and is a direct indicator of how the culture is developing.
Now all of this comes with experience. You don't know when to move on if you don't know just what color it is you are aiming for in the whey. The differences are pretty small, and inexperience will cause you to most likely overshoot -going for too much yellow or green which means too much acidity.
This is where pH comes in handy for the hobbyist cheesemaker. You don't need the experience to judge the whey, all you need is a simple test.
I think most of us here understand the importance of acidity. We can give a recipe telling you precise times to proceed to the next step, but what is important is that we proceed to the next step when the culture is ready for it.
And what about adding the rennet? how do we know if the culture is working, and we can proceed with this steP? After all, we don't have any whey at this step to judge, do we?
Actually, we do.
Before adding the rennet, our culture is happily working away to produce yogurt. It is already producing acid, causing the cheese to coagulate very slowly. What we have, then, are small pockets of liquid separating from the milk. When we see little tiny specks of green liquid on the surface of our cheese, we know the culture is working and we can go ahead and add the rennet.
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This is a fairly old post from you, Alpkäserei and I don't know why I only just found it now as it is a subject that I am interested in and has caused me MUCH vexation right from the start of my interest in cheesemaking.
Thank you for this very interesting and informative post. It is most helpful and reassuring for me too! (I STILL can't afford a ph meter!) I made a successful Mozzarella this week by accident but I don't know what the acidity was at each stage, however your description of the colour changes in the whey do match what I was seeing in this make. Now to duplicate that success! I will read your post again and follow the described indicators.
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Thanks for that explanation. I have a ph meter but don't use it much. I have tried to incorporate using it but I got the expected ph levels wrong and over cooked my cheese trying to reach the wrong ph level, so I went back to using the time in the recipe instead.
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Oh, Tammy it sounds like your ph meter may be in need of calibration. I have heard that they are sensitive and sometimes erratic instruments and need to be kept in some kind of fluid and calibrated carefully fairly regularly.
From all I have read, and the advice I have had from the experts on this site it sounds like knowing the precise ph level helps in duplicating the cheeses so that you can get the exact same result each time. On one level it is great to have something different and unique with each make, on the other you need consistency if you want to sell the cheeses (as I do).
It's all great fun though!
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Also conditions such as room temp which are fairly controled in a commerical settings may change at home and effect acidification in chesses which acidify during pressing. this is where relaying on time based recipes can cause you to under acidify or over acidify and where a pH meter can proove itself very handy.
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...or experience and careful observation can bring optimal results. Cheese has been made for hundreds of years before pH meters were invented, with consistent results.
Not everyone has to be tied down to technology!
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That's true Karen, and quite reassuring too, :) I have found that as time goes by I get more adept at recognising when things are going right and what needs to be done at that stage ... but technology is lovely! I absolutely ADORE gadgets. Father Christmas simply must bring me a ph meter this Christmas.
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I used Alpkäserei directions on my last 3 cheeses comparing that to the timing for each recipe, I noticed all points he is talking about are spot on ^-^
during each make it seemed to be easier to spot the next step, this can be nothing but a help in future makes :)
excellent information Alpkäserei :)
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I've been happy with the way my cheeses turn out, but have never done so scientific an observation as Alpkseri gives. I'll have to print this out and watch for all the signs before I make cheese again.
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Thank you for this instruction, Alpkäserei. With all the emphasis on pH meters, I've often asked myself how cheeses have been made for so long without them. This also answered some other questions I've had, such as why some recipes start out with large curds and then cut smaller over time.
Very, very helpful.
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I was curious about your description of whey color changes so I tried it side by side with a pH meter and watched the whey. Now, I may not have understood your points, and there is a small chance the pH meter was off, but from what you describe as the beginning point to the end, there was a .01 change in acidity. So I am not sure what to make of the method. I'm sure it's useful, but I am not sure it's useful in understanding acidity behavior. Have you ever done a side by side to compare with meter readings?
What we have, then, are small pockets of liquid separating from the milk. When we see little tiny specks of green liquid on the surface of our cheese, we know the culture is working and we can go ahead and add the rennet.
I also don't understand this. It's theoretically impossible at that high pH >6.5 for any gellation to occur with acid alone. Not without some other factor such as high-temp denaturation and/or solids manipulation.
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Alpkäserei,
How long approximately do you allow the milk to culture prior to adding rennet and approximately what temperature is the milk at this time?
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It's theoretically impossible at that high pH >6.5 for any gellation to occur with acid alone. Not without some other factor such as high-temp denaturation and/or solids manipulation.
Linuxboy, I've seen this happen often here in South Africa with raw milk that hasn't been chilled. It goes solid on it's own (and not horrid tasting) In fact it is called MAAS here and it's very popular.
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It's theoretically impossible at that high pH >6.5 for any gellation to occur with acid alone. Not without some other factor such as high-temp denaturation and/or solids manipulation.
Linuxboy, I've seen this happen often here in South Africa with raw milk that hasn't been chilled. It goes solid on it's own (and not horrid tasting) In fact it is called MAAS here and it's very popular.
What was the pH when it coagulates? I believe LB isnt saying that milk will not coagulate, but rather will not at such a high pH.
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It's theoretically impossible at that high pH >6.5 for any gellation to occur with acid alone. Not without some other factor such as high-temp denaturation and/or solids manipulation.
Linuxboy, I've seen this happen often here in South Africa with raw milk that hasn't been chilled. It goes solid on it's own (and not horrid tasting) In fact it is called MAAS here and it's very popular.
Banjoza - that is happening because the native bacteria in the raw milk are multiplying and creating acid. The acid is what "curdles" the milk and makes cheese - MAAS in your case. LB is correct. You have to have the acid for the milk to "gel".
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A friend of mine lives off the grid, no electricity. She lets all her goat milk coagulate on its own, then drains and presses.
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IIRC, maas is a sort of clabber. Just fermented milk left to culture with ambient bacteria. That will have a pH below 5.2 (5.2 is the earliest I have ever seen any kind of gel from a pure lactic set). I'm trying to understand the technology here, as from the description it seems like there is some wheying off before gellation due to bits of green on the surface. If there is discoloration, that's possibly chlorophyll or some other natural substance.
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"Measuring" acidity by instinct with no pH meter is going to depend greatly on the type of cheese being made. If you are like Alpkäserei and make the same (or very similar) cheeses over and over, then you might be able to tell when it's ready for the next step. But IMHO it is extremely difficult to develop those instincts if you are making vastly differing varieties.
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As Sailor said
"Measuring" acidity by instinct with no pH meter is going to depend greatly on the type of cheese being made. If you are like Alpkäserei and make the same (or very similar) cheeses over and over, then you might be able to tell when it's ready for the next step. But IMHO it is extremely difficult to develop those instincts if you are making vastly differing varieties.
My only point is I was able to see what Alp was trying to explain and yes you would have to do allot of the same type of cheese to get that familiar with the process,
I still use timing, without a PH meter I don't have the option or that information, until I am able to get one and for the few cheeses I make I cannot see the need or want to spend (at this point in time) another $100 or more for my small batches of cheese.
I just want to make an exceptable if not delightfull tasting cheese.
That being said, any observation's I can discern from the process is just another way to make the few cheeses I make and if that helps what the heck ^-^
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Sure, and I did not mean in any way to detract from the awesome suggestions and guidance. I'm trying to understand how some of the suggestions and details do not jive with my limited knowledge of microbiology and milk biochemistry.
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linuxboy you are correct. there is nowhere near enough acidification at this point to thicken the milk. we would have to let it set hours for this to happen. the acidification pre rennt is slight, but it does show up. we can see the green spots appear, but they are small and when dealing with very small batches maybe even unnoticable.
i do suspect that the target points will vary greatly with different cheeses. i learned about this method, and it does work to produce an extremely consistent product ( CASALP applies some rigid consistency standards to this cheese) but this all comes with experience, and i was fortunate to learn from one of the best
we take the approach of only making cheeses that are closely related, and share similar target points. this is how we can be sure of consistency. our variations can be had from adding ingredients post make to our 3 basic cheeses
as far as biochemistry, i cant contribute much here as you lb are one of my major sources on the subject. i cant tell why this system works, i just know it does and has a rather impresive track record. i will say this, this leaves a lot up to personal jugment, which requires experience and preferably having seen it first hand. we cant possibly relate this over the internet, which why i make the suggestion, if you are going to use this method but are unfamiliar with the target points, pay attention to how your cheese looks, feels, smells, etc at certain ph levels. you have to develop a sense about this. and i must even say, at this point my own abilities pale in comparison to my teachers.
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That's so interesting. Do you think the green spots might be chlorophyll or something else like that? or maybe the cream is way more acidified in some spots than the milk... like the bacteria clumps to it so there are localized spots of high acidity? Otherwise, how can the whey separate without a gel?
If you can do it at all, maybe next time you go over, could you take TA or pH readings? I tried it your way and I saw what you described, but the pH barely moved at all. Maybe difference in culture? I really trust the traditional practices because obviously they work very well, hoping to find the biochemical justifications for why things are done a specific way.
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It's magic!
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Well lets look at evidence that we can observe easily enough.
Most of us have made yogurt at one time or another. A few of us have probably opened it up too early at one point or another. This we can see, that we can have a cultured liquid that would otherwise become yogurt if we left it to develop and incubate. However, at very early stages, what we instead have is somewhat sour milk with a few 'grains' of yogurt suspended in the mass. The milk does not gel consistently (this, in fact, is a well known 'problem' and is why commercial yogurt makers and many home yogurt makers blend their yogurt)
So it seems to me that bacterial cultures during their earliest stages of development do in fact tend to form in clusters and culture the milk locally.
Regarding your observation and measurements, I would have to ask what cheese you tested this on?
I would say it is almost certain that the visual methods are going to vary tremendously between cheeses. A cheddar will have much different signs than an alpkäse.
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I did it using your recipe for alpkase and a wild thermo blend that should approximate the native pH curve.
As for bacterial clumping, yes, this does occur. Bacteria do flocculate and thermos do form long chains. But milk is fluid enough to accommodate moderately even acid dispersion when the pH is that high. I don't see how even with that whey-off could happen. When it gets to be below 5.4, I could see the pH differential being high enough to warrant gellation gradients and slight whey pockets.
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What sort of wild thermo blend did you use? Just curious.
I don't know what to say exactly.
This we can assume:
Color change is the result of chemical change in the whey. this is a fact.
If we are experiencing a chemical change, the most likely scenario is that it is changing as a result of culture activity, specifically lactic acid production.
I work with lactic acid bacteria in a number of other situations (pickling, sauerkraut, bread starters, etc.) and through all of these I do notice a universal sign that lactic acid is at work, yellowing or at higher levels greening of the liquids. So we naturally would assume that yellowing and greening of the whey is also a sign of lactic acid production.
We can also observe a difference in taste in the whey during the process.
I don't know what to say, other than perhaps you misjudged the targets, or maybe the pH changes to progress at certain stages are in fact quite minute.
Regarding the pockets of liquid, it is also conceivable that these could be fat and oil precipitations. This is also something that occurs. Small amounts of fats/oils are loosed from the milk as proteins and sugars are consumed and these will naturally tend to clump together in pockets
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Morphologically under the mic, it looks like at least two distinct Strep, 3-5 types of lactobacilli that dominate. lb look like at least one delbrueckii, one that looks like a paracaseii. Hard to tell, they're too similar without genotyping. There's some leuconostoc and some lactococcus, too.
Thing is, color change could be chlorophyll. Or differences in fat color and fat rising. It doesn't necessarily have to be anything related to fat or acidity change. I get what you mean about the pickling, I see that, too, but I also have noticed a few other dynamics here:
- When I agitate, the color differences are very small in, say, kraut. More so, turbidity happens and everything becomes cloudy
- When I ensure the absence of light and total submersion, color differences are very minor.
In pickles, wild flora do tend to flocculate to the bottom and will ferment bottom to top (so do some wild strains of mesos, BTW). Many yeasts with cold temp ferments do tend to flocculate to the top, which likely changes the pH.
I am going to repeat this and see. I observed everything you said, even to rather dramatic changes in whey color, but without associated pH changes. I am also going to take sweet whey and add in acid with agitation in .1 pH changes to see if it does anything.
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The green/yellow color in whey is caused by Riboflavin (Vitamin B2) and other B vitamins that are pulled out of the calcium matrix and remain in suspension in the whey. I have several thoroughbred horse farms that use my whey as a feed supplement for race horses, in large part because of the B vitamins. The water soluble vitamins are much more readily available for nutritional uptake than the dried powder whey.
Riboflavin acts as a co-enzyme that quickly becomes water soluble during oxidation/reduction reactions. That could help explain what you are seeing with very little if any change in acidity.
We should all drink more whey. ;)
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This is all very interesting.
Testing is certainly the way to find the answers.
From the sound of things, I would guess that your culture is going to be quite close to what we wind up with.
If your kraut is turbid and you have cloudiness, then that's a flaw. We want our kraut water to be clear with nothing settled on the bottom. I think they tell me that if you have cloudiness and settling, that comes from yeasts and you do not want yeasts to grow.
Color differences can be very minor, but still perceivable. I just double checked and closely studied some of this year's sauerkraut, and here are some observations:
We have 2 batches, the early one is far more acidic (due to changes in the sugar/starch ratio of the cabbages from early to late time, which was only a few weeks) Neither have any solids precipitated out of the whey at either top or bottom. The liquid is not clouded when I shake them.
The early jars have noticeably greener liquid (these will keep better)
We ferment our sauerkraut in jars under water, covered over and placed in a dark room. We do this in the basement, keeping the temperature under 60 if possible (above 60, especially above 65, is generally when you run into trouble with yeasts)
As for the green globs before rennet, maybe it is nothing. We don't really watch for them or anything, I just always heard that if you see them, it means the culture is working well. Maybe that is an error.
I suppose we will have to subject this to further experimentation. I'm sure you will find something to do with all of that cheese ;)
Note that for the first color change in the whey, the change when stirring the coarsely cut curds before cutting to final size, there is going to be some protein precipitation going on (I think) where we have a white cloudiness resulting from suspended proteins and fats that are absorbed into the curd.
There are two ways to experiment with this.
We can follow the visual targets and watch for pH readings, or we can do the opposite and follow pH targets and observe any visual changes associated with them. If we did this, I would say that we would use pH targets in the ranges generally used for an Emmentaler.
Now with this I would expect that things really aren't going to line up perfectly. We won't have our visual targets fall right on with pH targets. one is probably going to lag behind the other. I am guessing that they work in curves that are not directly correspondent to each other, yet both follow the same general patterns.
The result of this would be that timing of certain tasks will be slightly different if you use one method compared to the other, but that the overall time factor for the cheese as a whole will be pretty much the same. That is to say, the pH when you go into the press will be the same, and the overall timing of the make will be the same.
So if this is the case, we really aren't going by acidity at all, but by unrelated visual cues that happen to fall in a fairly closely related pattern.
We start out with carefully measured amounts of culture and rennet, and we can expect our acidification curve to follow our visual milestones fairly closely. This is a theory that I feel satisfies the current evidence.
In your make of the Alpkäse, how was the finished cheese at the time of pressing?
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Thanks for the input, sailor.
The question that arises,
is the precipitation of the vitamins from the calcium matrix dependent on cultural activity (that is, does the culture directly or indirectly cause this change) or is it dependent on other factors, such as rennet activity, heat, etc.
If it is a side effect of the culture, then we can rely on it regardless of the strength of our culture (that is, it would occur slower or faster depending on the sped at which the culture is working)
We can look at it this way,
acidification is a good measure, but it is only an indirect way of measuring what we are most concerned about, the strength of the culture. If this were not true, than a washed curd cheese would not be possible. So we are using acidity as an indirect way of measuring how well our culture is working. Yes, acidity itself has certain affects on the cheese but even so, the underlying factor responsible for everything is the population of bacteria and for an aged cheese, bacteria counts are what is most important.
So this is why I say, measuring pH is one indirect way of measuring the culture.
and it is possible that the traditional visual and textural cues are simply other ways to achieve the same goal.
Visual cues and pH readings may not line up perfectly with each other, and are indirectly related at best, but both seem to share the same cause and are directly related to the same source, the activity of bacteria at work in the cheese.
So this instance where the color change occurs may not show very much change in pH, but may fall in line on the time scale close to the point where a pH target could be met.
Now there is another change in the whey other than color. The green may indeed be from b vitamins, but there is also an apparent texture change as well. Before the transformation we have a white cloudiness and after the change, the whey is more clear.
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The green/yellow color in whey is caused by Riboflavin (Vitamin B2) and other B vitamins that are pulled out of the calcium matrix and remain in suspension in the whey. I have several thoroughbred horse farms that use my whey as a feed supplement for race horses, in large part because of the B vitamins. The water soluble vitamins are much more readily available for nutritional uptake than the dried powder whey.
We should all drink more whey. ;)
Is the whey dried, Sailor? Or whole, liquid whey from your cheesemaking?
We should drink more whey? I'm glad I have critters to feed it to, because I can't stomach the taste. Yech!
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We should drink more whey? I'm glad I have critters to feed it to, because I can't stomach the taste. Yech!
I hear it's pretty good in a smoothy, although I haven't tried it that way.
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We should drink more whey? I'm glad I have critters to feed it to, because I can't stomach the taste. Yech!
I hear it's pretty good in a smoothy, although I haven't tried it that way.
(http://www.theswissbakeryonline.com/store/i/is.aspx?path=/Shared/ProductImages/beverages-other/381003-Rivella-Red-Half-Liter.jpg&lr=t&bw=300&bh=300)
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We should all drink more whey. ;)
I use whey from early drained cheeses (still containing alot of sugar, not very acidic) instead of water to brew coffee or "chocolate "whey".
Its extremly tastey and have alot fuller body to it from all the milk solids.
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The beverage I showed is a very popular drink in Switzerland. It is a whey-based soft drink, 35% whey by volume with carbonated water and a number of secret spices. Most foreigners hate it.
But since dairy is a central part of Swiss culture, people are accustomed to whey.
On the Alps (the farms) people will draw cups of whey from the vat to drink. It's good, and healthy.
Also whey is very good for your skin (maybe those b vitamins again?) and some people even bath in it.
The whey dawn from Alpine cheeses is flavorful and fairly sweet.