### Author Topic: What PSI do I need?  (Read 864 times)

#### Tobiasrer

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##### What PSI do I need?
« on: November 10, 2012, 06:13:26 PM »
I have been looking without success so far,
I am wondering if some one has a quick list of the PSI required for different cheeses?
All My books just have light medium and heavy, Or 10 lbs 20 etc but doesnt really tell the mold size.

Any help would be SUPER THANKS!

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#### smolt1

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##### Re: What PSI do I need?
« Reply #1 on: November 10, 2012, 06:27:28 PM »

#### Al Lewis

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##### Re: What PSI do I need?
« Reply #2 on: December 10, 2012, 04:22:30 PM »
Problem with PSI is most of figures given give you a pressing weight that is unobtainable for many home applications.  For gouda they state 2.84 PSI.  Calculate that for a 8" diameter mold.

2.84 * (area = π * r2) = 142.75 pounds

Now consider where they call for 11.35 psi for cheddar.  Probably not going to get there with our equipment.

#### bbracken677

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##### Re: What PSI do I need?
« Reply #3 on: December 10, 2012, 04:33:46 PM »
Depending on mold size, true....

For Cheddar you just go with the max you can pretty much. With a 5 inch mold I can come pretty close to the 11 psi.

Reading the link that was provided by Smolt, you see that the main purpose of the pressures is for an ideal knit. If you can get your curd temp to around 80F and can hold it while pressing you are way ahead in the knit area, versus trying to press under cooler temps.

#### smolt1

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##### Re: What PSI do I need?
« Reply #4 on: December 10, 2012, 04:38:27 PM »
Al, all you need is 600 lbs.

Try cheese forum search for "breaking news".

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#### bbracken677

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##### Re: What PSI do I need?
« Reply #5 on: December 10, 2012, 04:51:39 PM »
Holy cow!  LOL  nice!  Now I know the creaking noises were normal and not the whole thing about to blow...!!!

I won't worry next time I hit 10psi at all...

Thanks Smolt!

#### Boofer

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##### Re: What PSI do I need?
« Reply #6 on: December 11, 2012, 09:03:49 AM »
Problem with PSI is most of figures given give you a pressing weight that is unobtainable for many home applications.  For gouda they state 2.84 PSI.  Calculate that for a 8" diameter mold.

2.84 * (area = π * r2) = 142.75 pounds

Now consider where they call for 11.35 psi for cheddar.  Probably not going to get there with our equipment.
For those of us using a Dutch press...not a problem.

Extracted from my Double Gloucester:
"I applied a 25lb weight with 4 pulleys for a calculated pressure of 575lbs and 13.7psi."

-Boofer-
Let's ferment something!
Bread, beer, wine, cheese...it's all good.

#### Al Lewis

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##### Re: What PSI do I need?
« Reply #7 on: December 11, 2012, 09:16:42 AM »
Al, all you need is 600 lbs.

Try cheese forum search for "breaking news".

I'm not saying it can't be done, with the right equipment, just saying that most folks don't have the right equipment available.  As a tool designer I have to tell you that I get pretty nervous when folks start putting those kind of pressures on certain structures.  I realize that many of the presses sold have been well designed and tested for their rated weights but, what happens when some poor smoe decides he or she can add some pulleys to their 200 pound rated press and crank it up to 500 pounds.  Can you say catastrophic failure?  See my point?  Wouldn't like to see anyone get injured having fun making cheese.

#### Tobiasrer

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##### Re: What PSI do I need?
« Reply #8 on: December 11, 2012, 09:55:26 AM »
Maybe I am a little naive but why catastropic? wouldn't the let/foot or arm will break? And your using an 8" mold, you can still get the PSI just get a smaller diameter!

#### Sailor Con Queso

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##### Re: What PSI do I need?
« Reply #9 on: December 11, 2012, 10:23:20 AM »
I make cheese commercially every day and never press with more than 3-4 psi, even my Cheddars. My only exception is Cantal, which I rarely make. It's all about temperature, moisture control, and managing the curds as quickly as possible.
A moldy Stilton is a thing of beauty. Yes, you eat the rind. - Ed
www.boonecreekcreamery.com

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#### Al Lewis

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##### Re: What PSI do I need?
« Reply #10 on: December 11, 2012, 11:22:22 AM »
Maybe I am a little naive but why catastropic? wouldn't the let/foot or arm will break? And your using an 8" mold, you can still get the PSI just get a smaller diameter!

Not everyone thinks about that.  Some folks will just think it's okay to run a press past it's limits.  Hopefully it would fail quickly but, in some cases, it may hold the pressure and then come apart at the seams.  Anyone standing nearby could get hurt.  I'm sure smolt1 can understand the concern here.  Stored energy can be a dangerous thing if it is suddenly released.

#### Tobiasrer

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##### Re: What PSI do I need?
« Reply #11 on: December 11, 2012, 10:31:16 PM »
I would agree if some one is using a hydraulic press, maybe even a modified spring. But with a lever I guess maybe I am missing something. i mean the weight on the puleys should still only be a couple dozen pounds, so other then the arm or foot snapping (which could spit shards I guess) the only other issue I can think of is wrecking your table or chipping your floor if the weiths drop.
I am not encouraging people to just make random mods, and I would recommend think through what you are doing, and ask if you dont know.

#### rolsen99

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##### Re: What PSI do I need?
« Reply #12 on: December 12, 2012, 07:59:28 AM »
Here is kind of a noob question, but I am looking to do my first cheddar this weekend.  The recipe I was looking at (Tim Smith) stated to press at 50 pounds for the final press.  This equates to about 2.48 psi on a 4.75" diameter.  This is obviously considerably low compared to 11 psi.  And as Sailor states, he has the means to press at a temp and moisture level that has success at 3 - 4 psi.

Are the books out there just geared to noobs like me assuming that don't have the means to press higher?  Is there a standard for psi, or is it just trial and error?  It looks there are varied opinions on what works for everyone.

Luckily for me, I only will need about 8.5 pounds on my arm to achieve the pressure needed for 11 psi (small surface area).  I hung 10 on it last week to test the strength and had no issues.  It makes me question my "artisan" book.
« Last Edit: December 12, 2012, 08:06:15 AM by rolsen99 »

#### bbracken677

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##### Re: What PSI do I need?
« Reply #13 on: December 12, 2012, 09:42:36 AM »
It is whatever is needed to achieve the knit desired...The problem with something like that from a book is that is has to be something that is "one size fits all".

Granted, I would prefer to see psi's listed rather than just simple weight to press by, but they probably have listed the form to use. I have a book that suggests the form to use so the weights work for that size form. If you change the make size and change the form, then you will have to do some calculations to adapt the pressure to suit your form size.

I have been pressing my cheddars at 10psi, but based on Sailor's comment I may adjust that somewhat and see how a lower press weight works for me.

#### rolsen99

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##### Re: What PSI do I need?
« Reply #14 on: December 12, 2012, 01:15:26 PM »
It is whatever is needed to achieve the knit desired...The problem with something like that from a book is that is has to be something that is "one size fits all".

Granted, I would prefer to see psi's listed rather than just simple weight to press by, but they probably have listed the form to use. I have a book that suggests the form to use so the weights work for that size form. If you change the make size and change the form, then you will have to do some calculations to adapt the pressure to suit your form size.

I have been pressing my cheddars at 10psi, but based on Sailor's comment I may adjust that somewhat and see how a lower press weight works for me.

I learned my lesson here regarding discussing weights.  I downloaded Hamm's excel spreadsheet and will start using psi, it makes more sense now.