Author Topic: Pressing Pressures  (Read 5479 times)

Offline Wayne Harris

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Pressing Pressures
« on: November 01, 2008, 01:03:55 PM »
I am very new to cheese making.  I just made my first batch this week. I'm hooked.

But as I read and think about my equipment, I have a question about presses.

I see references to 10lbs of weight for 15 min, then increase to 40lbs for 12, then 50lbs for 24hours.
And, of course, for different cheeses, there are different recommendations.

But my question is this.  What does that 50lbs represent?  so.  for example.  if I have a 6 inch mold, 50 lbs on that press yields about 1.75psi.

Is that enough?  I don't think so.  But fact is, i don't know. 

A quick google does not yield any references to PSI for cheese recipes.  I see presses that can apply anywhere from 3-100 psi.   But, i don't see PSI settings in the recipes.

Thoughts on the correct PSI needed for a standard cheddar press??

Thanks.

Wayne A. Harris - in vino veritas


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Offline John (CH)

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Re: Pressing Pressures
« Reply #1 on: November 01, 2008, 02:52:00 PM »
Hi wharris and welcome to this forum.

It's a good question with no hard answer, as you say 50 lb on a 6" diameter cheese works out to 50/(pie x r2) = 1.7 psi, whereas 50 lb on a 4 " diameter hoop cheese is 4.0 psi, quite a difference.

The reality I think is the weights and durations in the recipes are guidelines only as there are many variables, how much whey have you removed before pressing, type of milk used, how hard a cheese you want after aging, how many holes does your hoop and base have to release the whey been pressed out, etc. So basically after you've done a couple of pressed cheeses you start to get a feel for it. Also, if you press at high weights for long time, there is normally very little whey coming out in last hours.

Hope this helps . . . John.

Offline Wayne Harris

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Re: Pressing Pressures
« Reply #2 on: November 03, 2008, 03:42:49 PM »
Well,  I built my own Cheese press



The way I calculate it, i am going to use about 2.8psi using this much weight.

showing my work:
[(weight of bucket)*(distance multiple from plunger)]/(Surface area of follower)
(32lbs*2.5)/28.25sqin
80lbs/28.25sqin
2.83lb/sqin (psi)

I think i can get up to 7-10 psi if i really had to.  But the fact is, i really don't know what is needed.

Simply specifying X lbs of force, in a recipe is just not giving me a complete picture here.

I must read on.

Thanks for your reply.

Wayne A. Harris - in vino veritas

Offline John (CH)

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Re: Pressing Pressures
« Reply #3 on: November 03, 2008, 05:34:58 PM »
wharris, thanks for the picture, looks great, nice and simple and mechanically stable, congrats!

Offline Wayne Harris

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Re: Pressing Pressures
« Reply #4 on: November 04, 2008, 07:29:15 PM »
I was asked to refine my math.  so here it is:
showing my work:
Constants:
1 gallon of water = 8lbs
4gal=32lbs
Distance  between fulcrum and wall pivot: 12”
Empty press weight=29lbs

My formula for measuring PSI:
Pressure per square inch=[[(weight of bucket)*(ratio of fulcrum distances)+ Empty press weight]/(Surface area of follower)]

Bucket distance: 30" from the fulcrum, which is 2.5 times the 12" distance from the plunger to the fulcrum.
Cheese Mold diameter: 6" (radius 3")

So....
((32lbs*2.5)+29lbs)/(3.1415928*(3in^2))]
109lbs/28.25in^2
3.85 lbs/in^2 (psi)
Wayne A. Harris - in vino veritas


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Offline Tea

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Re: Pressing Pressures
« Reply #5 on: November 06, 2008, 02:36:03 PM »
So how did the press work in the end.  Were you happy with the final result?  I must say that it certainly looks impressive.
Watching this one with interest.

Offline Wayne Harris

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Re: Pressing Pressures
« Reply #6 on: November 06, 2008, 08:55:59 PM »
It turned out ok i guess.  i have not eaten it...I think i will wait 45 days or so.
Anyway, here is the press's first 2lb wheel of traditional cheddar.



Here is my processhttp://bocephus.spaces.live.com/photos/cns!8AD74B74B344340E!292
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Offline Wayne Harris

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Re: Pressing Pressures
« Reply #7 on: November 06, 2008, 09:30:32 PM »
I found an answer to my own question.
" Press with enough pressure to create a smooth rind by the next morning. This is 25 p.s.i. to start. After 30 minutes take of the pressure and tighten the cheese cloths around the cheese. Increase the pressure to 40 p.s.i. for the rest of the time."

http://www.dairyfoodsconsulting.com/recipes_cheddar.shtml
Wayne A. Harris - in vino veritas

Offline Tea

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Re: Pressing Pressures
« Reply #8 on: November 08, 2008, 02:53:35 PM »
Congrats Wharris that looks very professional.  Hope you can last the 45 days before you open it.  Keep us updated with the final results too please.  So what is the next cheese going to be?

Offline Wayne Harris

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Re: Pressing Pressures
« Reply #9 on: November 09, 2008, 07:55:26 AM »
Next cheese?,  that is a great question. 
I have 6 gallons of milk ripening with MA11 for cheddar as I type this.
 
My son (17)has expressed interest a swiss varietal, and the the wife wants havarti.  I was leaning to a parmesan.

So,  I have a feeling its gonna be Havarti, Swiss, and Parmesan. 


In that order.

;)
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Offline Tea

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Re: Pressing Pressures
« Reply #10 on: November 10, 2008, 01:24:03 PM »
In regards to the havarti, are you waxing, or are you going to try the washed rind?  Just wondering, as I have been looking at a recipe for a while now, and wondering which way I should go.

Offline Wayne Harris

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Re: Pressing Pressures
« Reply #11 on: November 10, 2008, 02:44:00 PM »
Funny,  I've been staring at this decision too. 

I am probably not going to wax.  I do not plan to keep the havarti for more than 90 days. 
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Offline SalMac

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Re: Pressing Pressures
« Reply #12 on: November 22, 2008, 10:48:52 AM »
Somehow I missed this entire thread, great great press! Good stuff!

Offline Wayne Harris

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Re: Pressing Pressures
« Reply #13 on: November 22, 2008, 05:37:12 PM »
Just to cross the "Stockpots" thread Sal,  I used that press to apply 5.5psi to my 8in wide wheel of cheddar.
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Offline Wayne Harris

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Re: Pressing Pressures
« Reply #14 on: November 30, 2008, 07:21:36 PM »
I tweaked my press design.  I wanted to go to more PSI. 
I raised the lever arm up to over my head.
I used a longer "piston" arm
I installed a lower guide arm for stability.


This allows me to have a more stable piston.  This design will not allow the piston to slide away, or towards the wall.

This will also allow me to hang weight from the lever arm.
In this case, i am using a strap to hang one of my primary grape fermentation containers (32gal trash containers). 
The nice thing about it, is that my weight is only about 1 inch off the floor.  So if things break, it only fails 1 inch.

Without writing out all my calculations. (feeling lazy). I am getting 11.5psi, on my 8in wheel of traditional cheddar right now.

That is nothing compared to the 55psi that i heard they use for commercial Cheddar presses. 

 
Wayne A. Harris - in vino veritas