acidification issues - not enough in ripening and too much during pressing

[lrunyenj]

I am working on my second attempts at semi-hard to hard cheeses, specifically a Gouda-like cheese and a Manchego-like cheese using homogenized low-temperature pasteurized milk from store.  Last time, the cheeses were a bit crumbly leading me to think maybe they were too acidic.  I had with no pH meter to guide me at that time. This time I have a pH meter (yea!) which I am hoping will allow me to better follow what is happening during the make.   For the Gouda I followed Gianaclis Caldwell's "Hot water washed curd" recipe (with MA4001).  For the Manchego I mostly followed Mary Karlin's recipe (but used MA4001 instead of MM100 and ThermoB, from Caldwell's book) with pH target I found on this forum of 6.5 at rennet, 6.2 at drain and 5.3 at end of press.  In both cases, I noticed two strange things that I am hoping to get some thoughts on:

(1) When I add the starter culture and ripen for 45 min, I see very little change in pH (6.63--> 6.56 for Gouda and 6.59 --> 6.59 for Manchego (could my initial pH be wrong because I usually get ~6.62 for these milks).   Should I wait longer to see the ~0.1 pH drop showing the cultures are active and dropping pH to allow rennet to work better or just wait the recommended time and go?

(2) When I press, the target pH is reached well before the suggested pressing time, specifically in ~ half the minimum time in range given.  I am pressing using weight measurements from recipes in a ~ 7 inch mold (for 2 gallons of milk).  The recipes both were written for 2 gallons but don't give diameter of mold, so I can not calculate psi.   Note that, the pH going into the pressing stage is NOT particularly off for Gouda --> 6.3.  It was a bit low going into the press - pH 6 - for Manchego.   Pressing temps are kept near 72C.  Any ideas on why the acidification is so rapid and suggestions to try.

My gut is to start with a bit less culture, but that does not see right because I am not seeing much acidification in the ripening. 

Thanks in advance for any advice.

[River Bottom Farm]

Go with your gut. It takes a while for freeze dried cultures to wake up and start to multiply. Once they do, sometimes the milk will buffer pH for a bit. You obviously have active and alive culture so you can safely cut back on the starter amount to get closer on the pressing time. I wouldn't wait much longer for the initial drop than what is suggested but if you doubt the starter is multiplying enough to distribute itself evenly in the milk then wait longer

[GortKlaatu]

Use everything you learn to help you—time, pH,
Looks, feel, gut instinct.
But if I have to choose between time and pH, I go with pH. It is a more accurate marker of what is going on with your specific situation whereas time is a generalization that can not reflect what is actually happening in your pot

[cheesehead94]

I'm having a similar issue as we speak actually. Making Gouda tonight. Ph started at 6.73 and only got down to 6.60 at the time that I added hot water (after 45 min ripening with the cultures in and the 45 minutes with rennet in). Hopefully adding the water at 6.6 wasn't too early, I know 6.3-.5 is more ideal from what I've heard

[Susan38]

Well I finally found this post just now; I must have overlooked it earlier.  I know this is an older post, but right now I (and I think a few others) are having very similar issues as what Lrunyenj described in the original post.  So....not that about 7 months have gone by, have any of you resolved how to deal with this situation?  Is it a matter of seeing how the cheese turned out and if you liked it, simply use the pH's that you are coming up with...and if not, keep trying different things till you get what you like?  How did the cheeses turn out that you had this situation with?  Did you try backing off on the culture amount?  Or was there some other solution?

As for me, my Colby looks a bit underpressed and slightly slumpy because I took it out due to pH, so we will see in about a month how it turns out.

Susan