We have all seen recipes which call for you to perform a "Grip Test" towards the end of the cooking of the curds, at whatever is the highest temperature they reach.... That could be from direct heating, or using a warm water wash, which is usually followed by a period of stirring until they "feel" right.... Understanding that correct feel, in its various and subtle variations, is obviously the way the old-time cheesemakers did the job, before the day of pH meters.... so it would be helpful if those of you with a lot more experience than I could give us noobs their advice on how the Grip Test might relate to the pH....
I have been doing Grip Tests on every cheese I make for several months now, whether the recipe calls for it or not (I don't own a pH meter, and have no desire to get one).... In addition, every time I see one mentioned in a recipe, I try and visualize and understand what they are describing.... I have come up with a "scale" from soft to hard, that goes something like this.... Note, we only do Semi-Soft to Extra-Hard cheeses that are pressed in a mold....
1. Very Soft.... When you squeeze a small ball of curds in your hand, they turn to mush, and milky whey runs out between your fingers....
2. Soft.... The ball of curds compresses into a soft mass, with the curds melding together easily, and when teased with the thumb, tend to stay matted.... Individual curds, when pinched between the index finger and thumb flatten and tend not to rebound....
3. Medium Soft.... The ball of curds consolidates, but you can still see individual curds, and when teased with the thumb the ball starts to come apart.... Individual curds are a bit resilient, and bounce back to about half their original thickness after pinching....
4. Medium.... The ball of curds sticks together, but the curds come apart quite easily when teased with the thumb.... Individual curds are quite resilient, and return almost to their original shape after pinching....
5. Medium Firm.... The ball of curds still sticks together a bit, but falls apart when touched with the thumb.... Individual curds are quite firm, returning to their original shape after pinching....
6. Firm.... The ball of curds barely sticks together, and often breaks just when you open your hand.... Individual curds are definitely springy, offering significant resistance when pinched....
7. Very Firm.... I haven't experienced this (yet), but would expect this to be what Peter Dixon calls curds that will "bounce".... :o
Most recipes seem to want the curds to be about level 4. Medium, or so my limited experience indicates.... When I stop before this, I find the moisture quite high, and the cheese looses a lot of whey when pressed.... I can't remember the last time I stopped cooking the curds before they reached level 3. Medium Soft.... as below that the cheese has a tendency to slump.... Yesterday we made a Colby, where the recipe called for stirring the curds at 102*F for 60-90 min. until they were "springy".... I kept track of what the Grip was like, starting at 30 min, at which point they were "Soft".... At 45 min. they were "Medium Soft", and a 60 min. they were "Medium".... For most recipes, I would have stopped cooking at that point.... By the time 75 min. had gone by they were at the "Medium Firm" stage, and I stirred them for the full 90 min. before individual curds were what I considered "springy", which I describe above as "Firm".... At that point, the curds were partially drained and washed with cold water, stirred for 15 min. then partially drained and stirred at 86*F for 30 min. before pressing.... After 15 min. at 10 lbs. they were barely hanging together enough to flip the cheese, but after another 30 min. at 20 lbs. were well consolidated (though still soft), with only a few cracks in the rind.... After another hour at 40 lbs. the rind was completely closed, and very little whey was expressed on that cycle.... After pressing at 80+ lbs. (3.5 psi) overnight, only a further teaspoon of whey was released, and the cheese is quite firm....
This was the first time I had tried to produce "springy" curds, other than by cheddaring.... It was interesting and informative to see how the curds changed as they were cooked longer.... I will definitely be recording the results of my Grip Tests, using the scale above, for all future makes.... but I was wondering if there is any correlation to the pH in any significant and repeatable manner that could be quantified.... While the moisture content obviously decreases with cooking time (and temperature), it is also related to the curd size, determined by the Flocculation time and curd cutting.... Is the "Grip Test" only related to the moisture, or, for example would larger curds, cooked longer have a higher or lower pH than smaller curds cooked shorter, but with a similar Grip?.... Any comments from those more experienced amongst you will be most welcome....
Bob
Interesting concept... I'm sure there is some truth to what you're describing, especially if you're comparing similar/same cheeses across different batches.
Generally smaller curds are cooked longer while larger curds are cooked less so I'm not sure you would ever see the opposite in practice.
Have you made any higher temp Alpine or grana cheeses? Those curds go through almost zero pH drop in the vat but would easily qualify as a firm/very firm grip - simply due to the lower moisture content and higher cook temp. Curds are not really assessed for texture change; they simply need to hit the temperature benchmarks.
Whereas a cheese like Tomme is cooked to curd readiness - feeling the curd is an important part of determining readiness. I think for this cheese, pH is part of the equation, but if I have a batch that is reluctant to hit the mark I give it an extra degree or two to drop the moisture level and achieve the right feel. I don't think a pH drop is responsible for that quick texture change when I increase the temp. But then again, if the pH were not correct at that point, the curd definitely wouldn't be hitting the texture benchmarks either. :)
I had forgotten about this thread!.... Perhaps I should comment about the Colby we created while doing it.... Cooking until the curds were "springy" produced a rather dry cheese that tended to be somewhat crumbly.... It had a cheddary aroma, very slight at 1 month, that developed with age.... As it aged, it changed texture to being less crumbly, and the Cheddar taste increased.... What I find confusing is that my notes also state that while it seemed quite dry at 1 month, it appeared to become moister as it aged, and at 4 months we felt its moisture content was nicely balanced.... It also sliced better as it aged.... At 4 months it was a very nice cheese.... 8)
We just did another Colby, this time stopping when the curds were at level 4. Medium, and we did not stir the curds for the additional 30 minutes after draining and before salting.... I am hoping to see a moister, more pliable cheese as a result, that is not crumbly.... It was certainly easier to get it to knit....
Bob
I also use the grip test on most of my makes. It's a useful technique to estimate the curd whey content and firmness.
Also have a look at this variation: «Le test du pâton»
https://www.facebook.com/watch/?v=632527437724470 (https://www.facebook.com/watch/?v=632527437724470)
I'm a little different than other people in that I just use the "grip test" to assess pH and I pull apart curds (or mash them up against the roof of my mouth with my tongue) to assess structure. The higher the pH, the easier curds knit, so as the pH drops the curds will stick less and less. Without a pH meter it's super hard to asses the pH in curds in the 5.5 - 6.x region because there is very little flavour difference. But with the grip test you can get a pretty good idea. Jim Wallace also has a "stick test" (my name). You grab some curds and then turn your hand over. The curds will stick to your hand at a certain point. It's great for higher moisture curds where the grip test is not so easy to do. I don't know why the "stick test" works. It's opposite to what I would expect. I'm sure there is a good reason, though...
In terms of structure, I pull apart the curd and visually inspect if the curd has a uniform texture throughout. At first the moisture leaves the outside of the curd and so you get a kind of water balloon effect. As the curd dries out, the outside skin gets thicker and thicker until it makes up the entire curd. After that, as the curd loses moisture, it will actually get wrinkled on the outside. You can also feel the texture pretty well with your tongue after a lot of practice.
Generally, both of these things work pretty well for a wide range of moisture levels. You kind of determine the moisture level with the renneting time. So a high moisture curd will go through the same structure phases, but will still end up with a higher moisture level (at least in my experience). That's why I try to differentiate between pH, and structure rather than moisture level.
Once again, Mike, you have packed an incredible amount of information into one post.... 8)
I am going to have to read that several times to digest it.... but I hope to apply some of those "tests" in future and learn what they can tell you....
AC4U and many thanks....
Bob
Mike, having read your response (several times) I have another couple of questions.... I realize that a longer renneting time (higher Floc. multiple) makes for moister curds.... Are you saying that initial moisture content carries over into the "finished" curd, somewhat independent of finished pH or structure?.... with those things being related to time and temperature (for a given make)....
I realize that smaller curds dry out faster, and so do those with a shorter Floc. time.... Try as I might, when I use a longer Floc. time (eg. 4X), and a large cut (eg. 3/4"), I still can't keep the curds large, no matter how carefully I stir (the best I have done is bean sized).... Any suggestions about that?....
Bob
Quote
Are you saying that initial moisture content carries over into the "finished" curd, somewhat independent of finished pH or structure?
Yes, that's my experience. YMMV :-) It's complicated, though. The way I think of it is that the structure is really the *difference* between the inside and outside moisture. That ratio is somewhat independent of the amount of water. So if I have 2:1 moisture ratio between the inside and outside of the curd, that can happen whether the moisture is 5 or 10 (in imaginary "moisture points")
Similarly, the pH changes the way the curds drain, but I can easily make something like a crescenza with 20% yield, pH of 4.9 and that will never drain any more whey. Or an Alpine that's got 8% yield at a pH of 5.3.
Cutting smaller helps the curd drain, but cutting early means that the casein hasn't linked up as much so the whey (and fat) can literally just run out of it. Water that isn't in the curds to begin with doesn't have to drain :-)
So from your last statement, cutting early may (does?) lead to lost fat?.... It certainly makes the curds a lot more fragile and easy to shred.... ::)
Bob
Yes, again, in my experience it definitely does. You can test this yourself by looking at the yield of ricotta you can get when cutting at various multipliers. Cutting at 2 will yield quite a lot more ricotta than cutting at 3.
I haven't made Ricotta, but I get it!.... I tried the "stick test" last night, and the curds just fell off my (gloved) hand.... This occurred on every grip test I tried.... Do they stick at much lower pH?....
Bob
Nope. Other way around. When the curds are at a high pH they stick together. As the curds move to a lower pH they don't stick. *However* if you "case harden" the curds (by raising the temperature too fast when you are cooking them), they will form a dry barrier which sticks less, so it's not completely straight forward. Similarly for very moist curds, then will never not stick, which is why (I think) Jim does the "stick test" in his Reblochon recipe (grab a handful of curds in your palm, turn it upside down, if they stick to your palm, the pH is about right to drain).
When you make a Colby you've probably noticed that even though you a cold water wash and the curds have a strong membrane, they are really sticky at first. You have to keep stirring them after you drain to keep them separated and then at some point they just stop sticking. It's my feeling that this is due to pH far more than moisture.
I'm just confused.... I realize that the higher the pH the easier the curds stick together, and as they acidify more, they stick less, which is how the grip test works.... As the pH drops, they are easier to tease apart with your thumb.... eg. my notes in the first post of this thread.... I would have thought the lower the pH, the less likely to stick to your hand, but you state
Quote(grab a handful of curds in your palm, turn it upside down, if they stick to your palm, the pH is about right to drain).
indicating that they start out not sticking, and as the pH drops, they then start to stick "when the pH is about right to drain"....
I think on my 2nd Colby I noticed that as you "dry stirred" them, they separated more easily.... but that cheese ended up too dry and a bit sour....
Bob
Yeah, I don't understand how the "stick test" works either. I think the thing is that sticking to you hand and sticking to each other are different properties. But I've tried it and it does seem to work that way. At first the curds don't stick to your hand and over time, they start to do so. No idea why.
It's hard for me say say with any real experience at what ph curds will start to stick to each other as I have yet to have milk straight from the cow so it's rare when I get milk above 6.5 ph at 90F usually the raw goats milk I get is 6.5 to 6.6 at fridge temps then after heating to 90 F they are usually at 6.45 to 6.5 ph .
I think that they should be sticking by ph 6.4 because that is the ph to hoop the curds at for a tomme and other mountain cheeses , but if they are freshly cut they do not seem to want to stick to each other so I am guessing that it is not just ph but also how much calcium is in the whey or how much is coming out of the curd or possibly the difference between the outer skin of the curd and the inner ???. It's calcium at specific ph that causes curd to self knit but why do curds freshly cut at the ph window not just knit back together ? Curds that are the right dryness and ph want to stick so much so that I have to stir quite vigorously to keep them apart and draining evenly .
Not read about this anywhere , only that calcium cause the knitting
Gregore
Quoteonly that calcium cause the knitting
Ah! That's a crucial piece of the puzzle I've been missing. Thank you! I must ponder the ramifications :-)
@Gregore In my experience curds are happy to stick at any phase - just cut, partway through cooking, when they're ready to mold...
This is for Tomme and Alpine types. Fresh raw cows milk.
I think a lot of it has to do with the depth of the vat and how much pressure is on the curds. Home cheesemakers usually have 15" or less in their pot; commercial cheesemakers have 24-36" in the vat. Makes a huge difference.
Another thing to think about in this line of though is hydrophobic interactions. Curds have water loving and water repelling sides. These change with temp, ph, and calcium content. Its complicated, that's why if you want a constant product being able to accurately measure ph, temp, time are all important.
Bantam
Very interesting that depth of vat would have an effect , but I can see why .
As for the fresh raw cows milk curds liking to knit at any stage after cutting , for sure my curds made from raw cows milk that is how ? old , a week maybe a little more maybe less , they do not knit straight away usually takes 10 to 15 minutes of stirring ( I have never timed it so could be off by 50%) but I am also thinking that maybe the higher ph the milk the sooner the knitting as I noticed during the last batch of cheese I had to stir more than usual to keep them apart and the milk was a higher ph than normal so I am guessing fresher
Just found this and have yet to read through it
https://www.cheesescience.org/calcium.html (https://www.cheesescience.org/calcium.html)
Interesting ideas thanks
Gregore
Have a look at this other variation of the manual evaluation of texture/moisture content and readiness for draining.
https://www.youtube.com/watch?v=Tr_NVzryOjw&t=890s (https://www.youtube.com/watch?v=Tr_NVzryOjw&t=890s)
After he very lightly press some curd, he rolll it in his hand. If the curd ball doesn't break appart, it's ready to drain/dipping.
I suppose that there are a lot of variations of these tests among worldwide cheesemakers.
I don't speak French, but you state....
QuoteIf the curd ball doesn't break apart, it's ready to drain/dipping.
As curds are cooked longer, they dry out and the pH drops, so they break apart easier.... Do you mean that once it starts to break apart it is ready to drain?....
Bob
Word for word he is saying :
« I know it by hand, you know. The grain has become firmer, you see ? The ball must not break apart, it must hold together when we roll it like that, when the tome is... when it's good.»
I'm sure he is using that observation for many years and developed his own markers. At first, the curd is too soft to make a ball then when the curd is dry/acid enough, he can then make a ball. He then estimate how long he can keep stirring, expelling whey and acidify from what he observed with his curd ball test.
But your interpretation make sense. He probably let it expel whey and acidify in the vat as long as the ball can hold together in his test, and based on his feeling and long experience.
I find it very interesting to see the diversity of techniques developed by old and traditional cheesemakers.
If you notice, right at the end of him rolling it in his palm it starts to fall apart.... I think THAT is probably what he is waiting for, as it is likely a very precise consistency at that point (moisture, pH, calcium content).... As you say, years of experience.... Yes, it's great to see another method, I am going to try this along with my grip test to see how they relate.... Wonderful to see a commercial producer that is still "hands on" (cows to cheese), rather than the huge vats right at the end of the video, where it is done by machine....
Bob
I have tried rolling a "log" of cheese in the palm of my hand the last couple of makes, to see how that technique compares to making a ball of curds in your hand and teasing it apart with your thumb.... First of all, the log won't roll unless it's quite round, which is why you see him compressing it several times (to get it round).... The curds will stay together and roll in your palm long before you can tease them apart easily with your thumb, so IMO his test gives a higher pH for draining (than the "teasing" method).... As you continue to cook the curds, they start to fall apart when you roll them.... If they are not cooked enough, when you squeeze them, they extrude out the ends and through your fingers.... So, I'm guessing that his years of experience give him a relatively narrow pH range where the curds will stay together when he rolls them....
Bob
To tease this a bit more... I made a batch of cheese where the physical characteristics seemed to be developing just fine: flocc test, cutting, stirring, cooking, texture, grip test, draining, forming, and even into the press.
The pH never behaved properly even though the meter was calibrated. The taste of the curd did not acidify.
The cheese make was a loss.
Turns out there was not enough days gone by since the cow had received antibiotics.
The next make was fine/normal.
For me I tend to think of texture and pH to be two separate but related measurements.