I make kefir and use the kefir as the culturing agent for my cheeses. Not had any significant problems but I do have a question: how different is the time it takes for freeze dried cultures to provide the milk with the bacteria it needs to produce the acidity etc compared to my use of say, a quarter cup (or more) of kefir. Should I be testing the pH of the milk before adding rennet or before I pour off the whey or begin to press the curds or should I simply use the lengths of time suggested in the recipes I am using? Thanks
This is a good question! I recently tried to make a Bulgarian style "sirene" which is a brined cheese. The instructions I found were quite general - but included a buttermilk culture as well as Bulgarian yogurt. I made my own Bulgarian yogurt with l. bulgaricus and streptococcus thermophilus (the cultures come from Bulgaria).
When I went to make the cheese, for 4 litres of milk, I added about two tablespoons of Bulgarian yogurt first, then 1/8 tsp. of Probat 222.
So far, the cheese is very nice! But I have no idea what it's supposed to be like :)
Yes you should expect huge changes in timing . The closest analogy would be changing the temperature of something you were baking you would expect the times of bake to change .
The recipe you are using is based on some ones experience using an exact amount of culture .
If you do not know the ph markers for the cheese you want to make some one here may know.
Is there a published source for the preferred pH for standard types of cheese?
At what point do you test pH?
I'll tackle these questions in reverse, starting with Valley Ranch's question about when to test the pH:
Yes.
As in, you test the pH at multiple stages along the way, partly depending on the type of cheese you are making. For some, like a camembert or some types of blue, or for a Cantal, you are going to let the curds bottom out in pH regardless, so I personally don't often bother to check the pH on these. But for pretty much any other type of cheese, checking the pH is very, very helpful. For me, the key check points are these:
- Check the pH at draining - some cheeses (e.g., "Swiss" types such as Emmental or Gruyere) need to retain more of the minerals, which would get leached out by a more acidic whey; thus, these cheeses may call for draining the curd at whey pH of around 6.35 or so. (Making sure you get the curds fully cooked by that pH is part of the art!)
- Check the pH after draining, while cheddaring or while waiting for mozarella curds to reach the right acidity for stretching - generally you are shooting for pH (of curd, not whey) of around 5.3 or so. At this point, you will stretch the mozarella, or mill and salt the cheddar curds; the latter will greatly slow down/stop the acidification.
- Check the pH while pressing a cheese that has not yet been salted, e.g., an alpine style, or Gouda, or parma-style, or so on. For these cheeses, you want to get it out of the press and into the brine (or begin dry-salting) once the pH (again, of the curd, not of any expelled whey) reaches 5.4-5.3 - if you let it go lower, the cheese will come out very crumbly. Again, part of the art is making sure that you have sufficient time to drain and press the curd before reaching the target pH.
As for a book (published source) that helps with this, and a world of other questions, I find it hard to beat Ginaclis Caldwell's
Mastering Artisan Cheesemaking.
As for how the use of kefir would affect the timing and pH curves -- the only answer is to make some cheese and test the pH as you go, keeping good notes. In fact, the same is true when using the freeze-dried cultures - I have found that some packets seem to be far more active than others, so it is important to get a feel for how quickly a given packet of culture acidifies, and adjust accordingly.
If you drain Mozzarella and the curd is say 7 if you wait will it become more acid as it drains of sits?
Andy - Thank you very much. Very useful and I have the Caldwell but if memory serves me (and it doesn't always) she does not indicate preferred pH for each recipe. So I assume (correctly, I hope) that the pH is for the kind of cheese?
Valley, it will IF you have innocculated it with culture (or are using fresh, raw milk with its natural cultures). If you are using the 30-minute method, e.g., adding acid, it will not change unless there are some natural bacteria in the milk.
And by the way, if your curd is measuring a pH of 7 ... something is wrong with your milk! :) As I understand it, fresh milk should be 6.7 to 6.65 or so. Interestingly, the milk I am buying from the store is measuring very low - only 6.57. But it is still working - as well as store-bought P&H milk ever can - so I continue to use it.
Bernard, you are right that she doesn't call out pH for every recipe, or for every step along the way. My take on it -- which may be corrected by others more knowledgeable! -- is that 1) if there are pH targets for a cheese in the same family, they likely apply to any other cheese in the family unless specifically noted otherwise, and 2) if no pH target is given, even for the family of cheese, it may not matter too much for that particular step or that particular type of cheese.
One other thought -- which is implied in my earlier post, but not made explicit -- is that, in general, the problem I face is not trying to get the pH low enough; on the contrary, it is making sure the pH doesn't get too low at a given stage of the process. Again, for some cheeses such as the camembert/brie/etc. types or blues or Cantal, the pH is intended to bottom out, so I find those makes to be much more forgiving.
With a cheddar-type make, I think you can get away with letting the pH go too low in the cheddaring phase; the taste will be good, but the texture will just be even more crumbly, and it will be that much harder to get a good knit. If you let something like a Gouda get too low while in the press, you likely will wind up with something very tasty, but not really a Gouda - it will be closer to a cheddar in taste, and it will be crumbly rather than smoothly flexible. Or at least, that was my experience with my first two or three Goudas, until I got a pH meter and realized that they needed to come out of the press MUCH sooner than the recipe said.
With mozzarella, you have only a narrow window of pH that will work properly for stretching - too high and it won't stretch; too low and it won't stretch. This is part of what makes mozzarella one of the more challenging cheeses!
RE: pH, I just picked a number.
Quote from: valley ranch on October 11, 2016, 03:17:45 PM
RE: pH, I just picked a number.
I understand - you weren't meaning a specific pH, so you went with a "neutral" number.
:):):)
I guess my concern is the following: most recipes tend to use freeze dried cultures and when the recipe calls for a 1/2 t or whatever the measure is and suggests that there is no need to wait before adding the rennet does that same time frame apply if I am adding kefir? And if the time to "ripen" is say 15 minutes if I add kefir will my cheese develop the same characteristics in 15 minutes or should I be allowing the milk to culture for a few hours or overnight? I was using the pH as an indicator of the amount of bacterial culture in the milk so if the pH dropped to say, 6 or 5.8 after the culture was added when the culture was lab manufactured freeze dried then I presume I should be waiting for the same pH even if that took all night...
The only reason for waiting when adding powdered culture is for them to wake up and start multiplying .
If how ever you are adding a live culture you should be able to add Rennet straight away , especially if you are using a kefir that was proofed over night.
If you have a ph meter you are looking for a drop of about 0.1 after the culture is added before rennet is added .
aha! Sp that is the secret - the 0.1 drop in the pH.. Thanks Gregore. That, I think, was what I was looking for.
Excuse me guys~I'm making cheese at the moment. My girls tell me the meter has been calibrated. ( don't know if it must be calibrated over and over)
The milk read: 7.9 at the start~mixed citric acid in water the mix read:2.6.
added the mix to the milk and the milk then read: 6.5.
I'm after Mozzarella, so I'm looking for about 5.3-5.5.
Added lipase, will check the pH
Added the rennet, I'll check the curd in a few~
How often do you calibrate your meter?
You only need to calibrate it when it does not read the 7 or 4 calibration solution correctly , I check mine a few times per make . If it Gets to 0.05 to 0.1 out then calibrate
Remember that it needs to be the same temp as what you are trying to get a ph level of . And they can take a minute or more for the fluid in the tip to come up to temp . As it comes up to temp the ph drops , so that means first reading will be a little higher than what it will end up after the temp stabilizes .
Valley, I'm not an expert on this, but I'm pretty sure milk should never be as high as 7.9 pH. I would be checking the calibration, and/or making sure the temperature has stabilized. Something is wrong somewhere ...
Should the pH be checked at the same temperature each time?
Ideally your pH meter should have temperature compensation built into it. On my Extech, it shows the temperature reading, and you can see its pH reading change as it rises to the temperature of the milk or whey or whatever. I often press the meter into the milk or curd and hold it there for 30 seconds or so before even turning it on, so that the reading stabilizes that much more quickly.
If yours doesn't have temperature compensation, that may explain the difference in the readings. Maybe there is a chart somewhere for how to translate the pH at different temperatures?? But honestly, though I have experience only with the Extech meter that I bought, I'd think this would be such an essential requirement that any pH meter would tend to include it.
FWIW, I have a vague memory that calibration on my Extech may NOT take temperature into account, so it is supposed to be calibrated at a specific temperature -- but I am not at all sure about that. I need to go back and check the manual. But that could also be a source of error ...
Well, thanks I'll have a go at it each time I make cheese and see what I get. I'll see about getting known pH water.
"known pH water" is distilled water. That should have a pH of 7
Better yet, get some 4.0 and 7.0 buffer solutions - these are available quite inexpensively (at least in this country) via Amazon.
Those solutions are a bit dear, but, I may give in. What is ATC, is that Automatic Temperature Control? ,,,,,,,,,,,,,,,,,,,Yes, I think it is (Temperature Compensation Automatic, 0-50 C, 32-122 F.
ATC does sound like temperature compensation. On my Extech meter, it takes a bit of time for the temp to settle - as much as 30 seconds.
The cost for the buffer solutions is all over the map, but you don't need to spend a fortune on them. Here is what I have been using: https://www.amazon.com/Atlas-Scientific-Calibration-Solution-Bottles/dp/B00SCADT3K/ref=sr_1_5?ie=UTF8&qid=1476882988&sr=8-5&keywords=4.0+buffer+solution (https://www.amazon.com/Atlas-Scientific-Calibration-Solution-Bottles/dp/B00SCADT3K/ref=sr_1_5?ie=UTF8&qid=1476882988&sr=8-5&keywords=4.0+buffer+solution)
$10 if you have Amazon Prime, or $10 plus shipping if not. Or you can pay $4 more and get twice as much (8 oz. bottles instead of 4 oz.). And better yet, they last a long, long time.
I don't calibrate every time I make cheese, but maybe every 3rd or 4th time. You only need a little bit each time, so these last a long, long time. I bought 8 oz. bottles almost two years ago (ordered them on October 29, 2014), and I still have about half of the 7.0 bottle and a third of the 4.0 -- I use the 4.0 a bit more quickly, because my Extech calls for storing the tip in a cap with a sponge soaked in 4.0 buffer solution. So I'd guess I'm going to get 3 years out of my $16 order! (Yes, it cost a bit more when I bought them, because I bought the bottles individually rather than as a set.)
Thanks for that!