Author Topic: pH Meters  (Read 3734 times)

Offline John (CH)

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pH Meters
« on: May 13, 2008, 10:33:20 PM »
My first try at making mozzarella failed I think because I didn't have the pH correct. To better prepare for try #2 I need a to buy a pH tester.

What's the best way to measure curd's pH and anyone have any recommendations, pros, cons? Options that I can see (from cheap to expensive) are:


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Offline DaggerDoggie

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Re: pH Meters
« Reply #1 on: June 08, 2008, 06:17:40 AM »
I don't have a PH meter, but I'm sure it would help.  I've seen on several recipes that it mentions to check the PH, but what should the PH be?  Is it basically the same for all or does it vary with the type of cheese?  I have found few recipes that mention when you should check the PH and what the acidity should be.

Offline John (CH)

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pH Meters
« Reply #2 on: June 08, 2008, 07:21:47 AM »
I've posted some info on acidification on the CheeseForum.org website. The milk is acidified (lower pH) by the starter or other cultures that are added at the start of the process. My understanding is that by measuring the pH at these early points, ie before adding culture(s) and then periodically after (until before pressing if hard cheese), you are are measuring the liveliness-vigor or lethargy of your starter and other cultures, an important parameter in cheese making.
« Last Edit: July 04, 2008, 10:53:42 AM by Cheese Head »

Offline reg

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Re: pH Meters
« Reply #3 on: June 08, 2008, 07:46:39 AM »
like yourself and DD i don't have or know much about PH meters ... yet.

looking at the info posted on the CheeseForum.org makes me think about the weak curds you fellows discussed in another thread. has me thinking was that the problem ? did the culture not have the time to produce enough lactic acid to drop the PH before adding the rennet ?

maybe the answer lies in having a PH meter and using it in a timely manner. my understanding is that different cheeses require a different PH level before adding the rennet.

again so much to learn and so little time
reg

Offline DaggerDoggie

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Re: pH Meters
« Reply #4 on: June 08, 2008, 01:07:16 PM »
You may be onto something, reg.  I have been following the instructions as far as temperature and time, which I guess is supposed to come close to the correct PH, but there are so many factors involved.

If we had PH meters and knew the correct PH before adding the rennet, the success rate may be more consistent.

Getting a PH meter is one step and then finding what the best PH for each recipe may really help us out.

Who will be the first to get a PH meter and track what works?


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Offline John (CH)

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Re: pH Meters
« Reply #5 on: June 10, 2008, 07:03:41 PM »
Found this professional Vermont USA website with Cheese Making Training and several Commercial (400 liter / 105 US gallon batch) Cheese Making Recipes, some of which have pH targets for certain stages.

Basically I think that commercial Cheese Makers can't ignore this more complicated control point measurement to ensure consistancy of product. Whereas hobbyist Cheese Making Recipes ignore it for simplicity, resulting in more varied / non-repeatable results due to different milks charcteristics and starter culture strengths.
« Last Edit: June 11, 2008, 05:13:12 PM by Cheese Head »

Offline reg

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Re: pH Meters
« Reply #6 on: June 11, 2008, 07:00:38 AM »
thanks for posting that site CH. had a quick look at it but will check it out it later today.

reg
reg

Offline DaggerDoggie

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Re: pH Meters
« Reply #7 on: June 11, 2008, 11:31:49 AM »
CH, that is a good find.  At least now we have some recipes with reference to pH levels.

There are also quite a few recipes on there, if we can cut them down.  I don't plan on making any cheese in the near future with 100 lbs of milk.

Offline John (CH)

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Re: pH Meters
« Reply #8 on: June 11, 2008, 05:15:26 PM »
Just corrected my post above, 400 liters = 105 US gallons which is ~400 kg / 880 lb of milk! Now that would make a lot of cheese ;D  ;D! Probably even new velward hasn't got that many goats/milk . . .
« Last Edit: June 11, 2008, 05:17:38 PM by Cheese Head »

Offline DaggerDoggie

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Re: pH Meters
« Reply #9 on: June 13, 2008, 05:52:05 PM »
He's my very unscientific theory on pH and some of the problems I've been having at times.  I've been following the times in recipes very closely, yet looking at the site that John posted above, http://www.dairyfoodsconsulting.com/recipes.shtml  and many other small farm type cheese making sites, they make their cheeses in large, open vats.  Many recipes call for the starter to mature for 45 minutes to an hour and this is in our small pots, normally with the lid closed.  The larger makers seem to have that time around the same or longer, and granted, there is a larger amount of milk, but there is a correspondingly greater amount of starter.

Surrounding that large vat, there has to be a fair amount of ambient bacteria in the air (which has been discussed here before) and even though the conditions I'm sure are very clean, there is still bacteria.  Much more can enter that vat than our relatively small, closed pots.  I would think that open air space would have an effect on the bacteria growing in the pot.  I assume the starters we use are aerobic bacteria and not anaerobic...I am sure they have to be.  Perhaps my (our) starters are starving for oxygen?

Then this morning I hear this on the radio http://www.npr.org/templates/story/story.php?storyId=91448837
The twentieth anniversary of "The Most Important Microbe You've Never Heard Of."  I found it interesting that 20% of our oxygen comes from this tiny microbe, but again, I digress.  I am trying to use up time before adding the rennet, however.

So, this evening I am letting my starter sit a while longer while making John's Manchego Cheese Recipe.  Hopefully I will get the pH a little lower or more importantly, correct.

That's my theory and until I invest in a pH meter, I'm sticking to it. ;D


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Offline DaggerDoggie

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Re: pH Meters
« Reply #10 on: June 14, 2008, 06:56:41 AM »
After extensive testing, one batch, ;D this seems to have worked.  My cheese set up very nicely after an hour.

Pictures posted here: http://cheeseforum.org/forum/index.php?topic=167.0

Offline John (CH)

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pH Meters
« Reply #11 on: June 14, 2008, 08:03:29 AM »
Thanks DD, helps to explain it, many cheese making recipes say mix in starter culture, wait 10 minutes to allow to ripen, then add rennet to accelerate and build a nice tight curd.

The reason for the Starter Culture is to "speed and control the process of curdling milk by starting the convertion of lactose into lactic acid which raised the acidity helping to make the curd" and with maturing to add aroma, texture, and flavour. So in theory, given long enough by itself, it will make a curd, but most recipes call for adding rennet to form a better curd for expelling whey (basically dewatering milk).

Thus as you said and proved (OK as you say only 1 batch), extending the time between adding the starter culture and rennet allows the culture to further ripen, producing more acidicy (which is normally not measured in home cheese making) and thus a better curd as shown in your pictures. I will also try this. One problem is how long and thus how acid before adding rennet?

But, I think most commercial cheese makers have uncovered vats as soon after the starter culture and rennet the curd is set and they need access to cut the curd. The other possibility as you point out is better access to oxygen in the air vs when covered? I think even when covered there is good access to air plus the curd tends to set throughout the milk instead of top down. Plus in the large commercial cheese making vats, it would take a long long time for oxygen to migrate to the bottom for the bacteria there. None the less, on my next cheesemaking, I will make in two pots, one covered, the other not and test that theory.

Your cut curds look great and are the tightest I've seen.

Offline John (CH)

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pH Meters
« Reply #12 on: June 14, 2008, 12:26:26 PM »
DD, I also found a whole bunch of pH info at Canadian Culture Seller www.symbiotechsolutions.com, just go English > Cultures > Choose Cheese Type, Click on a product to get pop with info including pH. Have fun!
« Last Edit: June 24, 2008, 03:31:02 PM by Cheese Head »

Offline DaggerDoggie

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Re: pH Meters
« Reply #13 on: June 14, 2008, 06:08:24 PM »
Thanks John, that is a good find.

I'm going to have to take some time and read through it.

Offline John (CH)

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pH Meters
« Reply #14 on: July 03, 2008, 06:21:28 AM »
Ordered my battery digital pH meter off of ebay here in USA for USD16+8 shipping on Friday, shipped via surface mail on Monday, arrived Wednesday.

So far looks good, it has two probes on bottom, one is clear and looks like an optical probe, the other maybe a temperature probe for correcting the pH reading. Directions say to insert the tool up to the end of where the cap seals, about 3 cm/1.5 inch. Should work well with reading milk and whey pH, I don't see how this is going to work for reading curds unless very soft.

Just now need to make some cheese to see how it performs.
« Last Edit: July 03, 2008, 06:31:19 AM by Cheese Head »