Author Topic: pounds or psi...I'm so confused  (Read 195 times)

Offline Jeepyj

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pounds or psi...I'm so confused
« on: May 18, 2015, 06:23:34 PM »
Since this past weekends cheese disaster turned experiment, I'm still determined to make pepper jack. I have three 'recipes' for pepper jack that all end up with

" Press at 3 pounds of pressure for 15 minutes.
Take the cheese out of the press, unwrap and flip it, rewrap it and place it back into the press at 10 pounds of pressure for 12 hours."

For the 3 pounds "of pressure", do i put a (roughly) half gallon of water on top of my mold to make 3-4 pounds or do I put 150 pounds of weight on my 8" diameter mold? Seems like theres a little difference there.  ;D

Online smolt1

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Re: pounds or psi...I'm so confused
« Reply #1 on: May 18, 2015, 06:48:57 PM »
Some of the authors of cheese making books are also very confused. First there is no such thing as pounds of pressure. pounds is a measure of force(weight) not pressure ( PSI....Pounds per square inch ). For your specific problem, The intent of the recipe is probably to press with 10 lbs of weight. To get 10 PSI of pressure on an 8 inch mold you would need 502 lbs of weight.

Offline Jeepyj

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Re: pounds or psi...I'm so confused
« Reply #2 on: May 18, 2015, 07:04:12 PM »
probably?

 ???

Online IllinoisCheeseHead

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Re: pounds or psi...I'm so confused
« Reply #3 on: May 18, 2015, 08:09:56 PM »
I have found that the best way to go about this is to determine what mold is the author using and how many gallons is the recipe for and determine if the author meant PSI or actual pounds of pressure.  It is unlikely that the author meant 10 PSI because you would need to apply 10 pounds per square inch computed as

              Square inches = pi (3.14) times radius times radius

For your mold it would be 3.14 times 4 times 4 which would total 50.24 square inches.  If the author meant 10 PSI, indeed you would need to press at 502.40 pounds.

When in doubt look at the whey coming out of the pressed cheese.  If it is very cloudy back off the weight / PSI.  The purpose of pressing is to remove the weigh and fuse the curds but not to compress them to the point that you would expel the good stuff. 

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Re: pounds or psi...I'm so confused
« Reply #4 on: May 19, 2015, 12:00:27 AM »
For a Jack the force seems about right  - if not a little light on.. I would press it between 8-10 pounds between two planks if you like a rounded cheese for 6-8 hours.  The main aim is to both encourage the whey out whilst retaining enough so the lactic acid builds up and the rind closes.  Dont over press otherwise it tends to end up dry and not very tasty.

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Offline Jeepyj

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Re: pounds or psi...I'm so confused
« Reply #5 on: May 19, 2015, 07:02:00 PM »
Thanks everyone. I won't be a noob forever.

Offline Raw Prawn

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Re: pounds or psi...I'm so confused
« Reply #6 on: May 20, 2015, 03:30:41 AM »
I think the best approach is to treat the values given in recipes as guidelines and experiment a bit and this.....
When in doubt look at the whey coming out of the pressed cheese.  If it is very cloudy back off the weight / PSI.  The purpose of pressing is to remove the weigh and fuse the curds but not to compress them to the point that you would expel the good stuff.
... is probably the most important guideline of all.
I would suggest that if you are unsure, err on the side of a lighter weight. If you don't get a good knit, increase the weight and/or the pressing time.
The heaviest pressure I've used was about 6 PSI on a Cantal and that was enough.
- Andrew