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So I tried to follow GC's cold-washed curd recipe and add some peppers after draining. Since I have had problems with the pH dropping too fast with my MA4001, I used 90% of what was recommended. I also use less rennet because mine not only seems to be double strength, but even when I would cut the dose in half (which is what you would think you would do) the flocculation times would still be markedly faster. So I also used 90% of what the recipe would have indicated were it in fact written for double strength rennet. I did not even get to go through all of the steps as my pH was dropping much too quickly for that. The overall pH of the cheese when it went into the cave was 5.01 according to the new Extech I picked up. The make went roughly as follows.

2 gallons cream line milk  (pH=6.74)
0.54g MA4001
1/4 tsp CaCl
0.65 mL double strength rennet
2.5% of salt at weight after draining
1 tsp each of red and green bell peppers
1/2 tsp crushed red pepper flakes

Added cultures @88.5F. Sit 5 minutes. Stir 3 minutes.
Ripen 40 minutes. pH-milk=6.67
Add CaCl, stir 3 minutes.
Add rennet. Stir 1 minute. Flocculation occurred 12 minutes after addition to milk. Flocculation factor=3
*Goal flocculation time was 11m 40s so I think ~90% of rennet is good
Clean break @ 36 minutes.
Cut into 3/8" cubes. pH-whey=6.40
Cook and stir while increasing to 102F over 45 minutes.
Held temperature and stirred and this is where I began to have to deviate, the recipe says this portion should take 60-90 minutes and you should have a pH of 6.2 with the correct texture. After 50 minutes I decided to check the pH and saw I was already at 5.65. I skipped the next step 15-30 minutes of letting the curds settle as well and moved right to draining.
I drained 1/2 gallon of whey and replaced with 1/2 gallon 60F water and stirred over 5 minutes. The temperature dropped to ~90F instead of the target 80-86F, but I had only boiled so much water and certainly did not have time to prepare and cool more.
Curds weighed 1175g. Added 29 g of salt and peppers mellowing over 2 applications and 20 minutes.
Pressed in 5" rounded mold (made it into a nice looking sphere and it only cost about $10)
Room temperature of 73F

Pressed with 6 lbs. for 15 minutes (whey was draining but the curds didn't even start to knit)
Pressed with 15 lbs. for 15 minutes (this time the curds stayed together) I flipped with every increase in weight after this point.
24 lbs. for 15 minutes
42 lbs. for 15 minutes
78 lbs. for 15 minutes (rind was almost closed)
150 lbs. for 30 minutes. At this point the rind was closed and when I checked pH-final=5.01.
So I pressed for 10 minutes without the cloth to try to smooth out any cloth marks. Then into the cave it went to dry. It slimmed down to 774g.

Notes:
1. It took me 9m 30 sec to cut the curds and about 1/2 way through they were not cutting smoothly like they had been at first, they seemed to almost be tearing a bit. I think I may want to invest in a curd cutter of some sort if anyone cares to recommend one they have had good luck with.
2. Next time I should either use less culture or significantly shorten the cooking time before checking pH and draining.
3. Boil more water than what I expect to use to prepare for the wash to achieve the correct temperature after the wash.
4. The curds had a good taste after seasoning and before pressing, perhaps use 1 tsp of the pepper flakes as well to add a bit more heat.

I too have an Extech and for whatever it is worth a degree in Chemical Engineering.  I think the Extech is an OK pH meter when used properly but it is not a great pH meter.  One several occasions the Extech has given me inconsistent readings especially when jamming it into the curds for a reading.  Now I wash the tip with warm soapy water (between readings) before storing the unit in distilled water.  I've even had to take a toothpick and dig out a little crap near the glass electrode.  The liquid in the little sponge in the cap is pH 4 buffer solution.  In my experience MA-4001 is not an especially "hot" culture and based upon the fact that you cut back the amount I'd suspect that the Extech might be giving you false readings. 

Of course, I am assuming here that you calibrated the Extech in pH 7 and pH 4 buffer solution before you made this batch.   Right?

Wow -- a drop from 6.67 to 6.4 just in the 36 minutes of coagulation? That seems like a huge drop to me at that stage of the process!

Do you know what the .56 grams of culture would translate into in terms of teaspoons or millilitres? Since I measure by volume rather than by weight, it is hard for me to envision exactly how much culture you are using.

The .65 mL of rennet sure sounds like a tiny amount!

Kern, I too sometimes get inconsistent readings from my Extech meter, but I generally can tell that they are inconsistent as I'm trying to get the reading, or by the time I take a couple of readings -- I would expect to see fluctuations up and down, not a consistent downward curve. But I have to confess that I too am careful to clean the electrode before using.

@Kern. Yep. I calibrated the meter. This was the first time I had gotten to use it too. I did not clean it with soap between readings, I did rinse it with DI water though, I didn't think to order any kim wipes and am wondering if not drying it between readings may have thrown stuff off a bit.  In my chemistry classes that was all we did between readings was rinse with DI water and wipe with a kim wipe. Is there something about the cheese making process that you think necessitates the use of warm soapy water prior to taking another reading? I mean, you are right of course that if some solid thing gets stuck near the electrode you would need to remove that, but I am just curious (I am assuming you mean you have a degree in Chemical Engineering?) what else might be going on?

@awakephd I am thinking, with respect to the 6.4 reading, that perhaps I did not wait as long as I needed to for the reading to stabilize. The number had not moved in awhile though. The 0.56 grams is roughly 90% of a 1/4 tsp. I use a scale that measures to 0.00g precision. The rennet I use is double strength rennet so using 0.65mL is like using 1.30mL of most rennet that is out there. I used 13 drops as an estimate and my flocculation time ended up being within 30 seconds of where I had hoped it would be. I have been using roughly 45% of what most recipes call for in single strength for my last few makes and have been getting flocculation times that have usually been pretty close to what I would expect.

I remember reading in GC's book that the goals are simply shape, drainage and a closed rind. What I had figured was since no more whey had been collecting in the bottom of my pan, the rind seemed closed and the shape seemed good that it was good to go, but I guess not. I had to go back to my cave and look at the cheeses and our newest edition had started to flatten out a bit and get indentation marks because my shelving is just coated wire sitting over shelves that were meant for wine. It caused a crack in the rind too so I threw it back in the press for awhile longer, I guess that is a reason to eventually make a trip to the lumber yard(which is unfortunately not too close) and cut some shelves to fit my cave. Unfortunately I did not think to take a picture then and a couple hours later, I moved the press to the basement which is a bit cooler to hopefully slow any further acidification, the crack is sealed up again.  Now I am wondering if their is a shortest length of time one might want to press is? Also, I am thinking of throwing a draining mat on top of the shelf when I put it back in and am hoping if it sinks again, which I would be okay with if it doesn't cause cracks in the rind, that this will stop any deep indentations. It would almost be better if it did sink a little bit as its height currently makes me have to remove the shelf above it to fit.

Hey Dan,

I was just working on writing some details about pressing procedures and I'll post here to answer your question along the lines of what I was working on to help answer your question,

First, for many cheese types -especially alpine and washed curd styles- most of our acidification happens in the press, not in the vat. So when timing your pressing you need to keep this in mind. If you don't press it long enough it may not acidify enough (I don't use pH when I make cheese, but I think I've heard that for my alpine style cheeses the pH should be something like 5.4 out of the press. But that could be totally wrong so don't take my word for it). If you leave it for too long the cheese may get sour and turn crumbly later on.

I like to leave a cheese in the press for no less than two hours, and that is for a soft cheese that acidifies fairly quickly. To determine proper pressing time, I like to use the following formula for my alpine and related washed curd types (I'd consider a jack to follow guidelines similar to raclette):
for soft cheeses, where the temperature is not raised above 110 degrees, I like to press for about 15 minutes per pound of cheese or at least 1 to 2 hours (I'm working with larger cheeses, usually no smaller than 10 pounds for my soft cheeses, so the 15 minute per pound guideline is what I follow) These cheeses acidify fairly quickly and will continue to acidify faster even after cooling down.
For semi-hard cheeses cooked to around 115 degrees, I press for 1/2 hour per pound or at least 2 hours. Again I'm working with larger cheeses.
For hard cheeses, cooked to about 125, I press for 1 hour per pound of cheese, more or less.

I hope this answers your questions about how to approach the issue of pressing.

Have you ever seen the little notes in Caldwell's book on what to do when something isn't going as planned -----I'm pretty sure she has one on what to do if your ph is dropping to fast.
I learned pretty quick on washed curds to have twice as much water than you think you need, ready to go, just in case.
Never had 4000 series drop to fast-----but maybe your temp was higher then you thought? The amount sounds about right. But then again my 4002 is getting a little old.
Qdog

Alp, a good guide (and a good teaser for the upcoming book!), but note that he salted the curds before pressing, so there should have been limited acidification in the press (though still some, I expect).

Quote from: WisconsinDan on July 10, 2015, 12:41:31 AM
@Kern. Is there something about the cheese making process that you think necessitates the use of warm soapy water prior to taking another reading? I mean, you are right of course that if some solid thing gets stuck near the electrode you would need to remove that, but I am just curious (I am assuming you mean you have a degree in Chemical Engineering?) what else might be going on?

I think that the electrode (s) might get a microscopic coating of fat from the milk/cheese that causes errant readings.  Warm soapy water gets rid of the fat.  The pH we are attempting to measure is ALWAYS dropping from the initial milk pH (~6.7 +/-).  The initial pH drop after adding culture is relatively slow because there are two few lactic bacteria to make much acid.  Still, there is some acid made and thus the pH is dropping.  About the time of renneting the pH is around 6.4 +/- 0.1 or so.  If your pH readings are initially following the pH versus time curve and then suddenly deviate then suspect the meter, not the biochemical reaction rate.  A big clue that the meter is "lying" is when there is no drop for a while then a large drop a few minutes later or worse when the meter shows a rise in the pH after showing a drop.  I've had this happen, cleaned the electrodes and then got a reading about where I expected it to be.  My last reading of the whey occurs right before draining and my first reading of the curds is right after draining.  I wring any residual whey out of the curds and expect the curds to have a pH about 0.3 +/- lower than the prior whey reading.  I'll get a curd reading about a half hour later following the first flip.  Again I squeeze out any residual whey.  Looking at these two readings I get a good idea of how fast the pH is dropping.  I always clean the electrodes between these reading as this is where you can get fat and tiny chunks of curds stuck in the meter between the glass electrode and plastic base.  If these readings seem weird then I might measure the 4.0 buffer solution to make sure the meter is reading correctly.  Except for this I never reuse buffer solution (put it back into the bottle).  All future readings are taken on the now pressing curds in an area where I've carefully shaved off the rind with a sharp knife.  This gets rid of any surface fat and exposes fresh curd.  I might take two or three readings with each flip.

This method can be used when cheddaring curds or any other treatment before salting.  Keep in mind that the pH drop is slowly accelerating as time goes on and it will never run away from you.  In my experience the rate of drop is fastest from about 5.3 to about 4.9 and that the curve of pH versus time is always a reverse "S" shape with the most vertical portion in the 5.3 to 4.9 range.  Deviations from this curve indicate faulty readings.

 I urge everyone to go back to their Caldwell book and re-read the section on ph and how to use the ph meter-----I just did ---and it seems I forgot more than I remembered----and have been doing some things----I'll be polite and say "a little wrong"
Qdog

@Kern AC4U for the warm soapy water idea. I used it a bit in a make today and it helped a bit, but the meter still seems a bit touchy and it seems I may need to recalibrate it more frequently than I realized. Wrote a bit about todays experience here https://cheeseforum.org/forum/index.php/topic,14831.0.html if you care to take a look. I am beginning to rue only having bought the little 1 time use packets of buffer solution. Should have bought the big containers instead. Live and learn.

Extech----has or at least did have excellent customer service and backed their products well----if you are having real problems----they will help and will replace faulty equipment.
Qdog

Dan,

You may already know, but just in case -- you can get 8 oz. or even larger bottles of calibration solution on Amazon relatively inexpensively, including free shipping for Prime members. Here is what I bought: http://www.amazon.com/Atlas-Scientific-Calibration-Solution-Kit/dp/B007X5KAV4/ref=sr_1_10?ie=UTF8&qid=1437141767&sr=8-10&keywords=ph+buffer -- but there are a bunch of different brands and configurations, including some with the 11.0 buffer. I use little plastic cups to hold a bit of solution for calibration.

That said, I have not found it necessary to calibrate my meter every single time -- as long as I 1) keep the electrode clean, and 2) make good contact with the curd, pressing it in a bit, and 3) wait for the temperature to settle, it seems to give reliable/consistent readings. So far, after about 8 months, I still have at least half a bottle of the 4.0 solution left, and even more of the 7.0. (The 4.0 goes faster because of using it in the cap of the meter for storage.)

Of course, when checking whey pH, it is a lot easier to "make good contact." As for the temperature, I sometimes insert the meter and wait 30 seconds before turning it on to allow it to reach the temperature of the whey or curd. As I've gotten more used to using the meter, I haven't found it as hard to use immediately, taking the temperature correction "drift" into account.

If you are doing all of the above and still getting inconsistent readings, I think it is time for a call to Extech ...

It is definitely time to call Extech. Today the meter refuses to even attempt to calibrate from the 4.01 solution. It must be the meter because I tried several 1 use packets and the meter believes them to be around 1.89 which is too far from the +/- 0.1 that it requires to attempt a calibration. This is very disappointing, I have only used the meter for a total of 3 makes. I hope their customer service is still good.

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Re: pH Meters & Dairy - Measuring, Calibration, & Maintenance
« Reply #6 on: April 26, 2011, 05:37:26 PM »

    Quote

Yoav, if you're experiencing oddity, condition your meter, and if it still doesn't work, send it back.

To condition

- First remove oil. Do this by washing with regular detergent. Soapy water
- Second, remove protein. Do this either by soaking in 1% pepsin/rennin with HCl added (.1 M... about 2 pH) to activate it; or if you don't have pepsin/rennin, use those enzymatic contact lens cleaner solutions like Renu. They work just as well and are really cheap.
- Third, remove salts. Do this by soaking in an acid solution. Something like .1 HCl, or even vinegar, or citric acid.
- Fourth, unplug everything. Do this by soaking the end of the probe in hot, 80C saturated KCl solution (3-4 M concentration)

The big one is protein and KCl. If you do that and it's still wonky, not too much more you can do. except refill the reference solution, and/or replace the junction.

In fact you might want to read the whole thread.    https://cheeseforum.org/forum/index.php/topic,6917.msg49355.html#msg49355
Qdog