Gouda (and a pH probe!)

[DrChile]

This is my second Gouda since resuming cheesemaking but it's the first cheese that I tracked pH throughout.  It was my first time using the Extech 100 so I made sure I was constantly calibrating (which I assume you have to do, based on my past experience in the lab).  I based my recipe off of scasnerkay's recipe from May 2013 recipe as it had pH targets that I wanted to emulate.

Gouda 2.2.2020
3 gallons Indian Creek Creamery Whole milk (cream line - non homo, low temp past milk):  pH 6.5 at 65 F
I use a mother culture so I went with 1.5% which is approx 6 oz.
4 oz Ma4001
2 oz Flora Danica
1/2 tsp Calcium Chloride in 1/4 cup water
2 ml (40 drops) single strength calf rennet in 1/4 cup water

Flocculation multiplier 3
Key for below:  Time (min) - descriptions

0    - Added cultures to 65 F milk and stirred.  Brought up to temp uses sous vide set up
37  -  Milk to 86 F.  pH 6.58.  Added Calcium Chloride.  Stirred x 1 min.  Rest x 2 min.  Added Rennet.  Stirred x 30 seconds.
Floc in 7 minutes.  Multiplier 3

60  - Cut into 1/2 inch curds.  Then let rest x 5 min.  Stir gently for 10 min at 86 F.  pH 6.81
75  - pH is 6.41 so start with washing.  Started washing curds, in 3 rounds. Removed 12 cups of whey replacing with 130 degree water, while stirring, 20 mins. temp 92 F
95 -  Removed 8 cups of whey, replacing with water, stirring slowly a bit over 7-10 mins. Whey pH now 6.49  Temp = 94 F
105 -  Removed 12 cups of whey, replacing with about 8 cups of 130 F water, and temp increases to 100 F.  Whey pH 6.38.
120 - Hand pack curds under warm whey and then press at 0.9 psi (6 inch diameter mold) for 30 min. pH = 6.49
150 - Flip.  Press at 0.9 psi for 30 min. pH = 6.58 (weird, why it went up)
180 - Flip. Press at 1.6 psi for 60 min. pH = 6.43
240 - Flip.  press at 2.3 psi for 60 min. pH = 6.12
300 - Flip. press at 2.3 psi for 80 min. pH = 5.83,
350 - checked pH at 50 min - pH = 5.7
380 - Flip. press at 2.3 psi for 45 min.  pH = 5.58
425 - Flip press at 2.3 for 40 min.  pH = 5.45 at end of pressing.

To the Brine!  Weighs 3 pounds.  Plan to brine for 12 hours flipping once (3# x 4 inches)...

To be continued!  Pictured is the Gouda, the ricotta salata i'm making from the left over whey, and a rudimentary pH curve.

[mikekchar]

You are not the first person to observe the pH to go up during a make.  I believe the last person to notice it was also doing a gouda.  I think part of that is that when you add acid to the milk it liberates calcium phosphate from the casein micelles.  This will bring up the pH.  In many makes the pH is dropping fast enough from the starter culture that you won't notice it so much, but I guess that with the washing you are both reducing lactose *and* starter culture population.  Since all of the calcium phosphate is locked up in the protein, it doesn't get diluted and so the pH shoots up.

On the other hand, I also wonder about the precision of the meter in the mid 6.X pH range.  6.5 pH is pretty low for milk, if I understand correctly.  Given that it is bouncing around in that 6.5 range (which is not much acid, compared to something in the 5.X range) I wonder if we aren't also seeing some fluctuation due to lack of precision.  The specifications say +- 0.01 pH, but I would expect that to be at a particular pH since it is a log scale....  Not quite sure I understand...

[awakephd]

DrChile, AC4U for your good work and careful observations.

A couple of notes on the Extech - in general, I've found it to be reliable and accurate, within my ability to determine, but there are a couple of caveats. I have not found it necessary to re-calibrate during a make; I recalibrate only at the beginning, and maybe not even that if I am making several batches in a row. It will drift a couple of tenths, but not more - and some of that drift is likely temperature related.

However, with the flat tip, it is important to do two things:

• Keep the tip clean - fats from the curds can quickly start to throw off the readings, so I wash the tip before each reading - a little dish soap and tap water, well rinsed, and then dried with a paper towel.
• Ensure good contact with the tip. This is not a problem when measuring the whey pH, but when measuring the curds, it can be a bit difficult to get just the right pressure and angle to be sure there is good contact. I generally find that I need to take several readings of the curd, throw the first one away (it is usually off), and then average the rest.

Mike, FWIW, some of the store-bought P&H milk around here seems to be around 6.5 pH straight off the shelf.

[Susan38]

I've been using an Extech 110 for quite a few makes now, with a lot of help and advice from this forum and especially Andy (awakephd) and Susan (scanerskay). 

I have a bit of a science nerd in me, so at first I was going willy-nilly with the thing, trying to take measurements on lots of stuff quickly and calibrating often.  I soon found out when I did this, the unit would go bonkers and give readings all over the place. I've since learned to settle down and take readings only when necessary, and calibrate only when the readings are off when testing in the 4 and 7 buffers.  Even then sometimes a number can seem a bit off, but if it's within the range of expected results, i don't bother continually retesting (because if I do a whole lot of time can go by when I should be doing something with the cheese instead of playing around with the unit).  I'm still dialing in a set procedure that works consistently for the unit and myself, but I think I'm getting there...as I know you will too. 

Hope this helps. 

And that's great you're getting your final pH in the proper range after pressing...(I'm still sleuthing why pH on my cheeses seem to tank too fast while pressing...)

AC4U for your gouda, and the time/energy to make ricotta salata after the gouda make!

[scasnerkay]

I *usually* check calibration before a make, at least in one solution. If it checks really close, I would call that acceptable and proceed.
If I am not being lazy, I check the pH before adding starter, because my milk is from the farm and changes seasonally. If I was using store bought milk I probably would not bother since that milk is generally standardized.
I might remember to check before renneting, but sometimes not until after cutting. Then again when I am getting close to draining, and when pressing.

EVERY time I use the probe, I either run a bit of soap on the end and rinse thoroughly, or I swish it in soapy water, rinse, and then leave it resting in 4.0 solution.

If I get readings that just seem inconsistent with expectations, I do a recalibration.

Periodically I do a "deep clean" using a series of electrode cleaning solution, rennet, and contact lens cleaner. The link to that process is somewhere on the forum. Supposedly that is to help remove all proteins that might be preventing an accurate reading. I usually follow that with a removal of the battery pack hard reset. Then re-calibrate!

[DrChile]

Thanks all for the hints and tips!
I totally think that there could have been an error in the first 1-3 measurements as I was getting used to the probe.
It's reassuring that I don't have to calibrate that often as well.

I'm anxious to see how this turns out.

It was surprisingly satisfying to see the pH curve go down as the pressing went on....

Trent

[DrChile]

after the brine I've noticed that the surface is a little slimy which is likely due to my brine being too low in salt (correct?) or maybe too low in CaCl2?... probably need to remake another saturated brine, or add some CaCl2
I've used this one for 3 cheeses.  It was a 20% saturated brine initially, so I wonder if it's truly lower in % or I just need to up the CacL2

bummer...  hopefully the sliminess stops as the cheese dries out

Trent

[scasnerkay]

I have used the same brine for several years. I store it in glass jars in the house refrigerator, because it seemed to pick up a sour or yeasty smell if stored at the cheese refrigerator temperature.
I heavily salt the tops of the cheeses while brining, to add salt replacing that taken up by the cheese.
The brine goes through a fine strainer into the jars in between cheeses.
Occasionally it is "pasteurized" at 145 or so. I have checked the saturation using a BRIX hygrometer from wine making.
Having to make a new batch of brine with all that salt does not sound like fun..

[DrChile]

ph of brine was 4.9. 
Likely may need to add more calcium Chloride or add more salt.

we shall see...

[awakephd]

In general, I don't think the salt content would affect sliminess one way or the other. Calcium content is a very likely suspect, followed by pH being off. Your pH of 4.9 may be a little low - you want it to be the same as the cheese, of which most types usually go into the brine around 5.1-5.3.

FWIW, I got tired of fiddling with / storing brine, and now I dry salt rather than brining. Thus far I've been very happy with this approach, but of course, YMMV.

[DrChile]

Excellent - i was just gonna ask what the pH should be... 

Trent

[mikekchar]

I think the thing about brining is that over time your brine will naturally move towards the optimal place for cheese.  I always use a fully saturated brine for brining (30 something percent???)  I don't really understand the people who brine at 18% or whatever as it seems quite difficult to control.   As long as I have some undissolved salt in the brine, then I know it is fully saturated.  When I first made my brine, I added the same amount of calcium chloride as I would for that quantity of milk.  Again, over time the cheese and brine will exchange calcium and it will be just about perfect in the end.  I also added enough citric acid to hit a pH of about 5.3, I believe (it's long enough ago that I don't really remember).  Again, over time the cheeses will drain whey into the brine (my cheeses are usually about 0.5% lighter after brining).  If you make enough cheese, eventually your brine will just be whey.

There are a couple of downsides to this approach, though.  Over time as you get more and more whey in your brine, the ratio of calcium chloride to calcium phosphate will go down.  And because calcium phosphate will precipitate when you heat the brine, you will slowly lose calcium from the brine as you pasteurise it.  For that reason, I don't pasteurise my brine unless I think there is a reason to do so.  I taste my brine before I use it.  It tastes like cheese.  But that is definitely a risk -- I believe a small one, but I could definitely be wrong.

The other problem is that over time your brine will acquire lactose because there is still lactose in the whey as it is draining from the cheeses.  Eventually it will certainly start to ferment, I think.  I haven't actually noticed anything growing in my brine, but see "that is definitely a risk", above.