Author Topic: curd knitting on pressing  (Read 6014 times)

zenith1

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curd knitting on pressing
« on: April 03, 2009, 02:05:44 PM »
I have had two occasions where the curd did not fully knit on pressing(only one end). Both times it was when making Montasio or Manchego. What would cause this to happen? I was able to get a little tighter knitting by dipping in 100 degree water fro a few seconds and repressing, but not to my satisfaction.

Zinger

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Re: curd knitting on pressing
« Reply #1 on: April 03, 2009, 03:19:16 PM »
Good question, I am currently dealing with a similar issue. Following your thoughts, I wonder if introducing it to a pot of whey from a new cheese making process and then repressing it would help.

zenith1

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Re: curd knitting on pressing
« Reply #2 on: April 04, 2009, 01:10:39 AM »
I had another thought about this problem. I up sized the recipe from a two pound to a three pound cheese. I never thought about the change in curd volume, and thus the size and shape of the cheese mold used. The original recipe called for a two pound mold, I used one from New England Cheese Making that was for a 2-5 pound cheese(tomme shaped)for this cheese. The two pound mold that I have is conical in shape and now that I think about it, I have not had this problem using the smaller one. Maybe because of the increase in diameter I should have used somewhat more pressure. Only how would I determine what amount to use. Ah the art it!

wharris

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Re: curd knitting on pressing
« Reply #3 on: April 04, 2009, 01:31:17 AM »
There is a lot of discussion here in the forums about the topic of pressure. 
Here is a summary of mine.  Apologies ahead of time of this is review for anyone.

Most recipes call for 10lbs or 20lbs or whatever to be placed on the curds. Any discussion of "pounds" is a discussion of weight.  This is a measure of force.  Also, most recipes were (At least in the Rikki Carrol book) were written for moulds of 4 inches in diameter.  So if you want to use a larger diameter mould, you will need to adjust the force.  I have adapted my recipes to use pressure, not force.  Pressure is merely an expression of that force over the area it is pressing on. 
So, if Rikki's book calls for a 10lbs weight,  that really means .8psi. 

How do i get that?
Assuming we have a mould of 4inches in diameter, that gives us 12.5 square inches.  (A=PI*R^2)  that is 3.1415*(2*2)
 
So, 10lbs spread over 12.5 square inches of cheese is about .8 pounds of force per square inch.
 
So what does that mean? 
To me, what that means is that if you elect to use a 6in mould instead of a 4in mould, and want to use the same recipe, you will want to maintain that same force (.8lbs) per square inch. 
 
Example:
So if you have a 6 inch mould, It has 28.27 square inches of surface area pressing on the cheese. If you want to maintain that same .8 pounds of force per square inch, you will need to push down with more force,  in this case 22.6 lbs instead of the original 10 lbs
 
So even though you are using more down force (weight), the same the same pounds per square inch of force is being applied to your cheese.
 
Carter has worked out a great table of actual numbers somewhere.
« Last Edit: April 04, 2009, 01:38:52 AM by Wayne Harris »

thebelgianpanda

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Re: curd knitting on pressing
« Reply #4 on: April 04, 2009, 03:21:44 AM »
So one thought that just occurred to me, and this may be rather naive, is that given equal PSI since one of the goals of pressing is whey expulsion, wouldn't the length the whey would have to travel to the surface also be a factor?  Wouldn't that at the very least increase pressing time, if not other factors such as weight?  This is completely off the cuff, but I would think that PSI would be an important measure as long as the distance from the center to edge remained similar.  I could be totally off base though, I really have no idea how inter-curd whey moves or even if it is a significant factor in anything.

wharris

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Re: curd knitting on pressing
« Reply #5 on: April 04, 2009, 03:26:29 AM »
That is an excellent question to which i do not have a good answer.
 
As I mature my understanding of pressing, am inclined to believe that surface area is but one input as to how much pressure to apply. 
 
Depth of curd is another, Time in the press is another factor.
 
I am still thinking about these but am inclined to believe that the deeper my curd (for the same diameter mould, the more weight i will need to apply due to the resistance offered by the springiness of the curds themselves. I do not have good data to back that up.
 
 
 

zenith1

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Re: curd knitting on pressing
« Reply #6 on: April 05, 2009, 03:19:56 PM »
Wayne ,that is a very well thought out concept that you put forth. On reflection I believe that you are correct about increasing the amount of weight based on the surface area. Thank you for helping to clarify my thoughts on the matter. I believe as you do that the depth of the curds must somehow also play a role in the amount of weight and or time needed at pressing. Thanks again!

zenith1

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Re: curd knitting on pressing
« Reply #7 on: April 05, 2009, 04:33:55 PM »
Wayne- as a an add-on to my prior post, If I were using one of Rikki's recipe's that called for a pressing at 50lbs and the mold diameter was 7.4 in then:

1. the surface area of the mold is 43 sq in
2. the amount of pressure to be applied is ~ 172 lbs
am I getting the concept?

wharris

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Re: curd knitting on pressing
« Reply #8 on: April 05, 2009, 05:51:18 PM »
Good question Zenith.

If her book calls for 10lbs, it is commonly believed here in this formum that she refers to total force,  not pressure.

So if her recipe calls for 10lb,  She assumes a 4in mould and thus .8 pounds per square inch.

If you want to keep that same pressure on a 7.4in mould, you would need  34.4 lbs. 

How did I get that?  Your 7.4 inch mould has about 43 square inches. Her 4 inch mould had only 12.5 square inches.  Since you have more cheese square inches on your 7.4 inch cheese wheel to spread out that load, you will need to add more weight to keep up that same pounds per square inch.

So,  43 square inches x .8lbs/Square Inch = 34.4lbs

Make sense?


Tea

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Re: curd knitting on pressing
« Reply #9 on: April 05, 2009, 08:36:54 PM »
Just another thought.  The curd should also not have cooled to much during the transfer and first pressing.
Just my .2c worth.

wharris

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Re: curd knitting on pressing
« Reply #10 on: April 05, 2009, 09:22:09 PM »
Completely agrees with Tea,  I think warm curds knit better.

zenith1

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Re: curd knitting on pressing
« Reply #11 on: April 07, 2009, 02:18:35 PM »
another good point of discussion. That was my feeling also when it comes to curd temps at the time of molding. I read somewhere that typically the temp of the curds should not be greater than ~70 degrees at the time of pressing or you risk excessive loss of butterfat. Has anyone heard this before?

Michelle

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Re: curd knitting on pressing
« Reply #12 on: September 28, 2009, 09:04:56 PM »
Hi,
With regards to the curd not knitting together well, I think the main factors you need to consider are warmth of the curd and acidity.  If the curd is cold, no amount of pressure will help.

Regards,
Michelle

Offline DeejayDebi

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Re: curd knitting on pressing
« Reply #13 on: September 29, 2009, 02:21:37 AM »
There can be many reason why the curd didn't mat together well. One can simply be not enough curd for the mold depending on shape. Another is greasy curds or to hot curds, to wet curds.  Not enough "pressing" - which does not necessarily mean not enough weight.

I have always believed that the amount of time a cheese is pressed is at least as important if not more so than the weight it's pressed with.

I normally press with light weight. You should always start light and build up. I start with between 2 and 6 pounds.  I rarely press with more than 25 pounds on any cheese (7 inch diameter) but I almost always press for 12 to 24 hours.