Author Topic: Curd Collapse  (Read 4633 times)

mightyjesse

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Curd Collapse
« on: July 09, 2009, 01:53:30 AM »
So... I've gone through 8 gallons (4 different brands, all of which were labeled "pasteurized" only.)  of milk, trying to make mozz with citric acid. Every time, my curds form and seem OK, but then when I try to separate them from the whey and spin them, they collapse into a mess of... what looks like a flavorless ricotta.

I've done this recipe *flawlessly* 3-4 times with no problems. Now in the last few days, I've had NO success. Any ideas as to what might be going wrong? Could my rennet be bad? I've tried both the American Mozz recipe from Fankauser's page and the 30 minute mozz recipe from the Cheese Queen with the same results. I'm really starting to freak out here... This cheese is "due" to a group social on Friday, and I can't get it to work, all of a sudden...

linuxboy

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Re: Curd Collapse
« Reply #1 on: July 09, 2009, 02:09:58 AM »
Do you have a way to determine pH? Mozz is very picky about pH levels to get a proper spin. Also, have you tried using a starter instead of citric acid? Yogurt or buttermilk work well if you don't have DVI culture.

[edit] If your process and quantities are exactly the same between recipes and you achieve different results, then milk is the culprit.
« Last Edit: July 09, 2009, 03:23:52 AM by linuxboy »

Offline DeejayDebi

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Re: Curd Collapse
« Reply #2 on: July 09, 2009, 02:31:11 AM »
Odd ... one of my members had this happen and we seemed to have thought maybe the curds weren't drained well enough before recooking. They kind of disolved as I recall. Could be old rennent too?

mightyjesse

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Re: Curd Collapse
« Reply #3 on: July 09, 2009, 05:47:17 AM »
They kind of disolved as I recall. Could be old rennent too?

Does anyone know what happens when rennet goes south? Mine says it expires on Feb 11, but doesn't list a year.... (Malaka rennet from Whole Foods) I bought it in April, so I'm really not sure if they mean Feb of next year or they mean that it was expired when I bought it... I've made several wonderful cheeses with it, despite the date... But the last one was at the beginning of June.

linuxboy

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Re: Curd Collapse
« Reply #4 on: July 09, 2009, 06:06:24 AM »
Rennet (chymosin) storage stability depends on extraction method and storage environment (primarily temp). Properly stored, chymosin denatures very slowly. Typical degradation is 2-5% per year in coagulative strength.

I have used 5 year old microbial rennet with no measurable difference in curd formation. I doubt it's your rennet unless the entire batch is bad, but you've made cheese with it before, so it should be good.


Offline DeejayDebi

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Re: Curd Collapse
« Reply #5 on: July 11, 2009, 05:25:18 AM »
It would seem unlikely that four different batches of milk were all bad unless your fridge is bad. I supposed it's posible.

goatherdess

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Re: Curd Collapse
« Reply #6 on: July 11, 2009, 03:35:03 PM »
1. Are you using a different brand of store bought milk from previous batches?
2. Sometimes antibiotic or wormer residues in the milk can do that (not a comforting thought).
3. I am using 3-year-old rennet with no problems or changes; stored in the 'fridge.
 
I sure hope it worked out for you on Friday.


Ariel301

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Re: Curd Collapse
« Reply #7 on: July 11, 2009, 08:39:17 PM »
If the rennet says February 11, I am thinking that may mean it expires in February 2011?

Offline DeejayDebi

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Re: Curd Collapse
« Reply #8 on: July 12, 2009, 04:43:49 AM »
Odd that you have used different brands of milk and diffrent recipes with no success after previous sucesses.

There are only three ingredients milk, rennet and citric acid in one of the recipes and four -  milk, starter, lipase, and rennet in the other.

You've tried different milks and the only other common ingredient is the rennet. Is it possible that you have somehow oxidized the rennet?

mightyjesse

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Re: Curd Collapse
« Reply #9 on: July 13, 2009, 04:31:57 AM »
I finally got one batch to work, but struggled with the curds the entire time. They were grainy and didn't stretch much, but it still turned into a cheese... Eventually.

One question - Fankhauser uses 1.24 tsp of citric acid and the Cheese Queen calls for 2 tsp.... I have no way of measuring Ph... Is there really that big a range of measurment in the recipe that works, or is there that wide a range of Ph's possible from grocery store milk?

linuxboy

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Re: Curd Collapse
« Reply #10 on: July 13, 2009, 04:48:41 AM »
Yes, both are possible. Milk pH ranges from 6.2 - 7.2, depending on season, species, age of milk, etc. Store bought milk tends to be more around 6.4-6.8. And yes, the amount of citric acid also drastically affects pH. You need a very narrow band for mozz, around 5.1-5.3. If your citric acid has picked up moisture, or has slightly lower purity or dissolution rate, then your measurement is off.

That's why I don't like citric acid for mozz in home environments without a pH meter. If you use a meso or thermo starter, you can always lower pH by waiting until it spins, but what do you do with a directly acidified curd?

jimmyzshack

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Re: Curd Collapse
« Reply #11 on: September 08, 2009, 08:59:53 PM »
Hey i'm having this same problem. I'm new and just started trying to make cheese but i have tried 6 times and got the same results. FYI i'm using malaka vegetable rennet exp Feb 11 also Lot IB110. Maybe it is the rennet i ended up ordering a kit this morning bc i knew i was following the directions right.
« Last Edit: September 08, 2009, 09:25:42 PM by jimmyzshack »

hplace

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Re: Curd Collapse
« Reply #12 on: September 08, 2009, 09:23:28 PM »
Here is an explanation on pH that I posted to another topic:

In "American Farmstead Cheese" page 129, you can find photos of cheese being stretched at different pH levels. At pH 5.24, the stretch is ideal. At a higher pH (6.15), the cheese stretches, but is "elastic, fibrous, and chewy." The photo shows the cheese being very stringy. At pH 4.95, the cheese stretches somewhat, but is brittle and granular. At pH 4.83, "the cheese lost its ability to melt and stretch and assumed a brittle, granular consistency that failed to flow." The photo shows a glob of cheese that looks like a ball of rice at pH 4.83.

Here is a link to the other post. It may be helpful: http://cheeseforum.org/forum/index.php/topic,807.0/topicseen.html

Michelle

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Re: Curd Collapse
« Reply #13 on: September 29, 2009, 03:11:11 AM »
Yes, Feb 11 will be February 2011. Not the 11th Feb.  They are not that exact...