How do I know if the milk has ripened?

[taeagan]

I got the Leener's kit about 6-8 months ago and took my first stab at a farmhouse cheddar last night.  Unfortunately I only have access to regular old supermarket milk, so I started off with 2 gallons of regular supermarket pasteurized (not-ultra pasterized), homogenized, whole milk.  I heated it in a water bath to 90°F and stirred in 1/4 tsp of the pwdered direct set mesophilic starter culture, which has been stored in the freezer since I bought the kit. 

I'm concerned at the milk may not have ripened.  After 45 minutes held at 90°, it didn't really look like anything other than warm milk.  I wanted to follow the directions properly, so I went ahead and gently stirred in the rennet after that.  From then on everything seemed to go pretty well.  I let the curd set, cut it, drained it, pressed it, etc... The only thing that may have been off is possibly that - and I am guessing here - the curds were pretty wet.  Wetter than the curd that I got when making the quick mozzarella with the citric acid.  I don't know if that happened because of a problem with ripening or just because I didn't do a good enough job of draining the curds as I scooped them from the pot with a slotted spoon to the cheese cloth/colander. 

Is there a way to test for ripening?  Should it look or taste a certain way?  The Rikki Carroll book refers to pH testing, but doesn't say what pH range to look for.  What's the normal pH of milk and what should the ripened pH be?  I'm a homebrewer, so I have pH strips and a meter. 

[Tea]

I have never used the direct set cultures, and have only used the cultures that are prepared 12 hours before hand.  As these set the milk like yoghurt, I know that they are active.  With the direct set, I assume that you just have to know that the cultures are within their expiry date, as when added to large amounts of milk, there is no visible sign that the culture is working.

My book says that after the addition of the start the ph should be around 6.6 - 6.7, which I think is around the normal ph range for milk.  You would need to do trials yourself on the milk you have to see whether there was any significant change in the ph.

[Cheese Head]

taeagan, welcome to the forum and good question.

I also now use Direct Vat Innoculation starter for ripening, same as you, and same as you, I also get no visible change in milk from that before I stir in my diluted rennet as per time in recipe. But the starter culture continues to work on the curd even after coagulation and while aging. The good news is that you got a Good Curd Set.

On your possible moist curds, there are many pictures in this forum for reference points and on cheddar which I have yet to make so can't advise.

On checking ripening amount, you could either do it as most do which is based on recipe times and assume the starter culture is working as required, or you are correct in that could check pH. I'm also using store bought past homogenized mostly whole milk bought here in Houston Texas USA and have initial pH of 6.0-6.2 which is higher than Tea and yes it normally drops 0.1 to 0.2 at time of when I add rennet based on recipe time. I don't know where you live, so your initial pH may be different. If you want to use pH to know when to add rennet, then you are really into the next level of cheesemaking and it varies by cheese type. Not sure of the type of cheese you were making but there are several guides here on processes for different cheese types with their key, often pH control points.

Sorry for the long post, hope helps, again welcome.

[Cartierusm]

First off you won't see any visible change in the milk. Secondly, using PH as a guide is very hard and most of us on here are stuggling to come up with answers. So stick around and you'll learn with the rest of us.

As far as PH drop, John has it right, you should have a drop of .1 from your original PH. Milk will always be 6.9-6.7 no matter what. It's the nature of that substance no matter where it comes from. Usually what I do is take a PH after I pour it into my vat, it's always 6.9, then when it comes up to temp around 86-90 I take another reading, without adding anything it always is around 6.7, probably just the nature of heating up the substance, what ever is in the air helps ripen it a little. Then after adding my starter and let it ripen I get 6.6. Hope this helps.

[taeagan]

pH changes naturally with temperature.  There's probably nothing changing in the milk as the temperature rises, you just get a different pH reading at different temperatures.  Thanks for the replies. 

[Cartierusm]

Probably, but my PH meter is temperature corrected.

[Cheese Head]

Mine isn't temperature corrected, but that explains why pH goes up with temp and no culture added etc. Thanks taeagan.

[Cartierusm]

Which one do you have, becuase my old one that's cheap has it and I wouldn't have thought so either.

[Cheese Head]

Carter, good point, I have this one but I think I've chucked the pamflet.

[Cartierusm]

If it's was only $16 it probably doesn't have temp correction and if it's a noname brand it'll be hard to find instructions. Look at the ebay ad or the same seller and see if he has a description or has any more infor.

[Cheese Head]

Good idea, just found same unit on sale on eBay.com USA

Specs are:

• Range: 0.0-14.0pH
• Resolution: 0.01pH
• Accuracy: +/- 0.1pH
• Automatic Temperature Compensation: 0 deg. C to 50 deg C
• Power Supply: 2 x 3V (CR2032 Battery)
• Operating Temperature: 0 deg. C-50 deg. C (32 deg. F-122 deg.F)
• Calibration: Manual, at one point through trimmer
• Dimensions: 150mm*27mm*20mm

So looks like it auto corrects for temp, thanks, one less thing to worry about.

[Cartierusm]

There ya go.

[wharris]

(Putting on my thinking cap here)

Isn't the ripening phase of cheese production  a combination of the curing and maturation phases of cheese making?  Isn't it more correct to state that ripening occurs AFTER curd manufacturing?

I would think that the phase of cheese making that Teagan refers to would be better called the Stabilization and/or Acidification phases?

Stabilizing Phase:
-Adjusting the temperature
-Adjusting the CaCL2,
-Adjusting the fat (adding cream?)

Acidification Phase:
-Introducing a starter culture that converts milk sugars to lactic acid
-Adding back the previous day's whey production

I think her question is an important one because her question seeks to understand  how to tell when a cheese-milk is ready for the coagulant. And that is a tough to question to answer simply.  I don't have the technical chops to answer that question other than to say follow the recipe.

I will add that the acidification phase transcends other phases of cheese making, and will continue on its own till a specific pH is reached, (~pH4.6 for most meso strains), or salt is added (making life hard on the lactobacillus). Acidification also affects many aspects of the coagulation phase, (strength of the curds, curd dryness etc.) So the timing of the rennet phase would seem to be an important decision when trying to make a specific cheese reliably and consistently.  So much seems to be riding on that decision.

So far,  I do not have enough information as to make my own determination as to when it is appropriate add rennet other than following a pre-written regimen. 

I too would like better operational markers for determining various cheese making milestones.  I think, and this is a bit of a guess, that most recipes were first based on trial and error, then backed up by propeller-head science, then dumbed down to "wait 45 min".

The challenge I share is getting a tad more scientific than "wait 45 min", but less scientific than needing a PHD at the end of my name.

[Cartierusm]

To quote Pulp Fiction, "Look at the big brain on Brad". Yeah, Wayne A. Harris PhD. just doesn't sound correct when you know his PhD is in Macraroni art.

After all the struggles I've had to find answer to these questions I've realized a few things, many of which Wayne was kind to put above, so he get credit I'm just putting my point of experience to it.

I wondered for a long time about what some professionals call pre-ripening, the stage when you add starter to right before adding rennet. I do have some recipes that have titration levels in them but it's only for after you cut the curds and I've learned recently that most acid gets developed in the cooking phase.

So to control before adding rennet is very hard and impossible with a PH meter which is not sensitive enough. Gerrit says he has a PH meter that goes to .00, two decimal places, but PH is a different kind of acid measurement. When I make a BIG Stilton this week I'll take an acid titration and see if I can detect a change before adding rennet.

As Wayne pointed out go by time until you find a better method, but even my text book which gives acid levels doesn't give you an indication by measurement of pre-ripening. What they do is called a Marshall Rennet Test which by you let the milk ripen for a period then put a measured amount into a Marshall cut add a specific amount of rennet stir it in and release a plug underneath and it will stop when it has coagulated and you read the line it stops at in the cup. Then you know if enough acid has developed to coagule that milk in the right amount of time, but it talks nothing of acid measurement before adding rennet. I would suggest just go by time and measure every stage and keep notes and use the same manuf of cultures.

[wharris]

Insinuating that I might have a Phd. in the Macaroni Arts is to do a serious disservice to all pasta-based artistry.