I am trying my first cheese with the pH meter, and something isn’t working out.
I tried a hybrid of Dave’s Gouda recipe and my usual one, as follows:
heated 2 gallons of milk from our goats to 86 F
added 1/8 tsp DVI mesophyllic culture
(No CaCl, because I’ve read that isn’t needed for fresh raw milk.)
added 1/2 t rennet in 1/4 cup cold water
let set 1 hour (had a meeting so didn’t stop for flocculation test)
cut curd in 1/2” cubes
let rest 5 minutes
First pH check (with Hanna Checker): 6.59
After about 50 minutes of stirring, holding the cheese between 88 and 90, pH was flashing back and forth between 6.50 and 6.49.  Ten minutes later it was flashing between 6.50 and 6.51.
I gave up on lowering it and replaced 6 cups of whey with 6 cups of 130 F water.  The whey pH rose back to 6.59.  (Our water has high sulfur content. Would that make a difference?) 
Repeated in 7 minutes;temp about 97 F; pH rose to 6.65
Repeated after 5 minutes;temp about 98 F; pH rose to 6.67
Raised to 100 F, held 20 minutes, stirring occasionally
Drained whey ( I couldn’t picture how to press under whey); put curds in mold, pressed with 20 lb weight.  Whey pH 6.84
I’m pressing at at 40 lbs now as per my old recipe.  I’m not sure why I couldn’t get the whey pH down to 6.45 after cutting the curd, or why it rose instead of falling subsequently.  Could it be about the CaCl? Or something abut my goat milk? What’s the usual starting pH of your milk? (I didn’t think to check mine.)
Any advice would be greatly appreciated.

Hey Joanna,

I’ve only checked the pH on fresh milk once and it was quite a while ago; but I think it was 6.59.  The one thought I had about the rising pH is that your meter may have gone out of calibration.  That has happened to me on occasion.  If your readings are getting higher it would be a good place to start. This last cheese that I made, a cheddar, saw me with a 7.01 calibration at the start.  Then, when the pH got to a more acidic level, I recalibrated at 4.01.  I’ll be doing a Gouda tomorrow and I’ll keep an eye on things.  I ll let you know how it goies.  Of course, I don’t use goat’s milk - I use raw cow’s milk.

I had another thought this morning.  When you do your pH test, I assume you are rinsing your probe first.  When you insert the probe into the whey sample, try swishing it around a bit.  This will displace the rinsing solution that is around the probe tip and give you a pretty accurate reading without having to wait for it to equilibrate.

I have a system I follow when testing a sample. It might be over kill but it does work for me.

First I collect the sample in a shot glass.
I then rinse the probe in distilled water and dry on a clean paper towel.
I then dip the probe into the sample and swirl to get the reading.
Then I rinse the probe under tap water and finally place the probe back into a bowl of distilled water, where it waits for the next use.

As I said, this might be overkill but I’ve not had problems getting my readings by following this system.

Also, as Rich said, you do need to calibrate your meter from time to time (I actually do this before each and every use).

As for store bought milk, mine almost always tests at 6.61 when fresh.

Hope this helps.

Dave

OK, my Gouda is in the press now and here’s what happened with the pH:  My first test after healing was at 6.6.  It dropped in a reasonable time to 6.56, but then it stayed there for 45 minutes before it dropped any further - and that was only to 6.54.  All in all it took nearly 2 hours before the pH was at 6.44 and I could go on to the next step.  I don’t know how normal it is for the process time to be so slow; but I did notice that Dave’s recipe (which I was using this morning) calls for an initial 86 deg. F., where my other recipe calls for 90 deg.  That, in itself, would slow the process somewhat.

I had an Oops, and it leads to a question.  I got called away to do some chores while the Gouda was in the press and I didn’t get back to it until just over 4 hours into the press cycle.  When I took it out of the mold, there was a wee bit of whey on top of the follower, so I tested it, and it came to 5.05!  That’s way too acidic, according to Dave’s recipe instructions.  But the question is this:  how do you check the pH when the wheel is in the press and you’re getting no whey expelled????

I would press the probe lightly to the cheese and give it a min.

Rich,

Neil probably does have the right idea here, although I would be VERY careful doing so with the Hanna model. That little glass bulb is very fragile and could easily be damaged if you press too hard.

Although you are below what the final ph should be I think it will probably still turn out to be a good cheese. As long as you dropped it into the brine right away, it should still turn out.

On one of my Gouda attempts, (the first time I used my Extech meter) it took what seemed like an excessively long time to hit the correct drain Ph.
During that make I kept thinking that my new meter was faulty.
Well after letting that one age for a 6 month period I have to say that it was far and away the best cheese that I’ve ever made.

As I’m sure we’ve all learned, every make is different and doesn’t always follow the parameters of the last make. As long as things turn out okay in the end, OR if we learn something along the way then each make is a success.

Dave

Dave

Dave,

Thanks for the encouragement; hopefully it will turn out well.  I’m a bit concerned that it over-acidified and may be a bit on the dry side.  We’ll see; but it probably won’t be 6 months.  Also, I know the MM100 is a slower acting culture; but what had me mystified is that it never moved from 6.56 for such a long time.  Well, maybe it will develop more “character” in the finished cheese.