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GENERAL CHEESE MAKING BOARDS (Specific Cheese Making in Boards above) => STANDARD METHODS - Forming Cheese => Topic started by: beeman on January 23, 2009, 02:40:14 PM

Title: Mould size & pressure
Post by: beeman on January 23, 2009, 02:40:14 PM
I would like to revisit a post on this forum, which states that a larger mould requires more pressure. The premise being, that as the mould size increases in surface area then the pressure has to increase to compensate. This information is totally wrong.  A pressure of 50lbs on a 4 inch mould is still the same as 50 lbs on an 8 inch mould. The only thing affecting the results of that pressure would be an increase in height of the cheese in the mould.

Increasing the height from 3" to 6" of the curds in the mould would require a slight increase in pressure, but it is so slight that for all practical purposes it is not adjusted.
Title: Re: Mould size & pressure
Post by: wharris on January 23, 2009, 04:45:43 PM
50lbs is not pressure.  Its a measurement of force.  (Force = Mass X Acceleration)
Pressure, however, is defined as force per unit area applied.

While you are correct in saying that the force (50lbs) would remain the same, the pressure would in fact decrease as the area applied increased. (used bigger moulds)

That is why if you need a specific PSI for a wheel of cheese, you need know the area of the wheel, and adjust your applied force.

According to several authors, most books here are written assuming a 4" mould.  Within these books,  the two terms are sometimes used interchangibly.  That can be confusing.


Hope that helps....  :)




Title: Re: Mould size & pressure
Post by: chilipepper on January 23, 2009, 04:53:03 PM
Another thing to make sure we are clear on is the fact that pressure we are discussing is the pressure over the most common 4 inch diameter mold and how that translates to an 8 inch diameter mold, etc. 

Quote
The only thing affecting the results of that pressure would be an increase in height of the cheese in the mould.

beeman, I just want to make sure that we are on the same page in this discussion regarding pressure as it seems you are referring to increasing the height of the mold to 8 inches. Increasing the height would indeed have the same surface area as the mold diameter is not increased so pressure applied would be the same.  In this regard, both of the discussion are correct we just maybe need some illustrations! :)
Title: Re: Mould size & pressure
Post by: wharris on January 23, 2009, 05:00:49 PM
Regarding pressure (as expressed in PSI) and hieght of the curd in a mould,  I have been harboring a thought/question.

If my curds in an "X" inch mould were say 2 inches deep,  or  12 inches deep,  would you use the same pressure?

Would you get a good "knit" of the curd down deep in the middle on the deeper cheese?


Would a deeper cheese (of the same diameter) warrent an increase in pressure?

Title: Re: Mould size & pressure
Post by: Likesspace on January 23, 2009, 07:21:02 PM
Let me preface the following statement by saying that I am not an expert (by any stretch of the imagination) on this subject. The only thing that I do have is my own individual results.
When I moved from using a 4" diameter mold to a 6" diameter mold, I did so with no increase of weight and my wheels turned out fine.
Yet when I moved from a 6" diameter mold to a 7.5" diameter mold (and especially the 8" diameter mold),  I began to have a LOT of trouble.
Whereas before, my wheels would always knit together and come out very good, my first attempts at larger cheeses came out looking cracked and very rough from inferior knitting of the curd.
I honestly had no idea what was going on and only after asking for help on this board did I find out that higher pressures are required for larger diameter wheels.
At first I was skeptical (see my posts in the referenced discussion) but eventually came to accept that this information is correct.
I did eventually accept this information because:
 
1. I gave pressing at a higher weight a try and it worked (and has continued to work) perfectly.
2. I received information from Jim at New England Cheesemaking Supply, stating that this information is correct.

As far as being able to give scientific evidence of the validity of these claims, I am not able to do so.
I can, however say that it has worked for me, in my own cheesemaking.
Good luck to everyone no matter what method you choose to use.

Dave
Title: Re: Mould size & pressure
Post by: Likesspace on January 23, 2009, 07:59:06 PM
Btw..
I do feel that Beeman's ideas on the importance of milk are valid points.
After three years of making cheese, I'm just now discovering that small changes made in the starting product can yield drastic results in the final product.

Dave
Title: Re: Mould size & pressure
Post by: Cartierusm on January 23, 2009, 08:33:46 PM
What videos are you watching? Because the only videos I’ve found on the web are for entertainment on how cheese is made not an actual instructional video. If you have a link or an instructional video that teaches cheese making I’d be more than happy to view it.

So you’re saying when they press 15 50 lbs. wheels of cheddar in a row, which I’ve seen in person, the pressure remains the same? Because 50lbs of force wouldn’t even move the entire line of cheese let alone press it.
Title: Re: Mould size & pressure
Post by: beeman on January 23, 2009, 09:24:39 PM
If you apply 50lbs of weight to a disc of 4" then scale that disc to 10" there will still be 50lbs of weight required to achieve the same result. The weight at the edges would be the same, your position implies that the weight would diminish towards the edge of the mould, as the mould gets bigger.
The only time that internal pressure will change is if you increase the height of the cheese in the mould.

Likesspace. There are so many variables in making cheese, so it would be difficult to tie down what made the necessary change to improve your wheels. You have been talking milk improvements which will improve your melding when moulding.
Title: Re: Mould size & pressure
Post by: Cartierusm on January 23, 2009, 09:36:10 PM
I never made a position of diminished pressure toward the edge. I simple stated that the surface area of bigger molds increase and so should the pressure, it's all about pounds per square inch. Try this experiment take a 10 lbs. spring place 50lbs of weight on it. It collapses, then put 10 springs under the same 50 lbs., they won't even compress a little, well maybe a little, but certainly not very much, much less collapse.
Title: Re: Mould size & pressure
Post by: Webmaster on January 23, 2009, 09:56:55 PM
Hey guys, keep it civil!

Just to add my 2 cents to this topic, it is not just about dimensional data and weight, it would only be that way with a low viscosity homogeneous material like water. I think there are also the variables of:

The consequence is that cheese making is an art as in artisan which is why we all have so much fun making it ;D.

Anyway rightly or wrongly that's just my opinion.
Title: Re: Mould size & pressure
Post by: wharris on January 23, 2009, 10:50:57 PM
Civil it is then.  ;)

I would agree Beeman that from a cheese making perspective, there are certainly bigger fish to fry than cheese mould force/pressure. And I know all too well that I am not an authority on much here.  (which explains why am here and not doing this professionally)

But the relationship between force expressed as weight, that is applied to a specific sized area does have a mathematical relationship that is well defined. 
Pressure = Force/Area  (http://en.wikipedia.org/wiki/Pressure) Change the weight, or the area, the pressure changes.

The more salient question might be is pressure even important; what are the right pressures; when should they be applied relative to whey expuslion; and how important are the pressure numbers...
Those i do not have down.  I am still taking my own empirical data, and borrowing heavily from the more seasoned veterans here.


 

Title: Re: Mould size & pressure
Post by: Cartierusm on January 24, 2009, 12:05:14 AM
Wayne I thought you were the seasoned verteran, or maybe just seasoned.. ;D

I mean I've been trying to figure out if height of the wheel is something I should take into consideration as well.

There is just so little imperical data out there and tons of disinformation, that's why were here to discuss these things.
Title: Re: Mould size & pressure
Post by: wharris on January 24, 2009, 01:01:36 AM
As I delve into my library to research on pressing,  I find that the Aussies discovered back in 1962 that if you press cheddar curds in a vacuum, you get that classic closed cheddar curd without the need for "cheddaring"

So,  we can add vacuums to the discussion of pressure topics.

(my head is gonna start spinning soon)

 :P

Title: Re: Mould size & pressure
Post by: wharris on January 27, 2009, 06:31:09 PM
(Full disclosure:  This was a post of mine in the other forum that i thought might be reasonable to post here)
I was further thinking that for mould of a given diameter, there *may* be reasons to increase the force.

So,  for example, given the same type of cheese:

A mould that has a curd depth of 3” will require a pressing protocol.

That same mould that has a curd depth of 20” might require a modification of the pressing protocol.

I know 20” depth is an extreme,  But I wanted illustrate my point.  Curds do have a certain sponginess, and drag at the sides of the moulds that both provide resistance to pressing. This resistance would increase with depth, and may require more psi for the same diameter mould.

I might be overthinking it, and i certainly won’t be making any 20” tall wheels of cheese,  but I might make a wheel 10"X6”
Title: Re: Mould size & pressure
Post by: Cartierusm on January 27, 2009, 08:40:01 PM
Wayne I agree with you totally. I've got on my list of things to do to figure out the pounds per cubic inch and see where that gets me. I will be working from known figures I have of cheese after pressing. So I'll be figuring cubic inches from a compressed cheese.
Title: Re: Mould size & pressure
Post by: wharris on January 27, 2009, 08:46:37 PM
I think this kind of data is one data point, that mapped with others like %fat in milk, pH at various phases, Strains in the starter culture, all combine to form trade secrets.

These are the cards that real cheese manufactures keep close.
Title: Re: Mould size & pressure
Post by: Likesspace on January 28, 2009, 01:44:31 AM
Hey, once you guys get the math figured out on this, let me know......
Maybe I'll find a new cheese making forum (that you know nothing about) and  take credit for the information you come up with.  ;D
Honestly, you two have helped me a LOT with your pressing information.
I'll be looking forward to hearing your ideas on this subject.

Dave
Title: Re: Mould size & pressure
Post by: Cartierusm on January 28, 2009, 01:54:16 AM
Dave I've worked the math forwards and back and different ratios, I think it's fine the way it is. I tried figuring out the pounds per cubic inch instead of square inch and it's not that far off. But I think PSI is the way to go. You can't go wrong with my chart.
Title: Re: Mould size & pressure
Post by: wharris on January 30, 2009, 05:13:51 PM
Here is an article that talks about and actual pressure: 26PSI


"A study was made of the influence of several factors on the texture of young and mature vacuum-pressed rindless cheese. Pressures greater than 26 lb/in2 were required for maximum improvement in texture. A vacuum of 15 in was less effective than a vacuum of 25 in. Vacuum pressing of 'dressed' cheese for 5 min was almost as effective as vacuum pressing for 17 h; vacuum pressing after dressing was more effective than before dressing; transfer of vacuum-pressed cheese to a normal press for the completion of pressing did not affect texture. Vacuum treatment of curd before hooping and pressing in the normal way had no beneficial effect on texture; vacuum pressing improved the texture of cheese made with mixed-strain starters although this cheese was not as close as vacuum-pressed cheese made with single strain starters.

The distinct improvement in cheese texture which resulted from some combinations of vacuum pressing condition was confirmed in commercial scale trials involving 2,540 rindless cheese. This improvement was evident when cheese were graded at two weeks and when regraded at maturity."

Title: Re: Mould size & pressure
Post by: Cartierusm on January 30, 2009, 08:01:44 PM
I've just been reading the recipes in my Cheese and Fermented Milk Foods text book and they talked about every aspect of Parmesan, a whole chapter in fact, and it talks about ones that are pressed and ones that are not pressed. Just as I suspected, it's up to manufactuer, just like cheddar from two different cheeseries are different.
Title: Re: Mould size & pressure
Post by: wharris on January 31, 2009, 12:59:08 AM
Dang 'cheeserie' trade secrets..




(actually, i just wanted to say "Cheeserie")
Title: Re: Mould size & pressure
Post by: Cartierusm on January 31, 2009, 01:32:45 AM
I like making up me own words.
Title: Re: Mould size & pressure
Post by: valereee on February 03, 2009, 04:01:17 PM
Wow, I am so glad to have found this discussion.  I seconds ago  had a eureka moment and thought, "but putting a 2# recipe into a 6" mold doesn't change the absolute amount of cheese curds that need to be pressed...maybe that means the psi isn't the crucial factor.  Maybe it's the pounds per CUBIC INCH!" 

I JUST posted to the other forum, searched there on pounds per cubic inch and didn't find anything, so I came here to search and found this. 

People were talking about how taking a 2# recipe intended for a 4" mold and putting that 2# of curd into a 6” mold doesn’t cause problems.  But others were saying that while they hadn't noticed a problem when going from 4" to 6", they had noticed a problem when going from 6" to 8".  But when you go from a 6” mold to an 8” mold, of course you’re talking a much more massive cheese.  No one would put a 2# recipe into an 8” mold—it would be about half an inch thick.  And most people going from a 6” mold to an 8” mold are doing so because they -want- to make a more massive cheese, not because they want their 5# cheese to be flatter.  (PLUS most people going from a 6" mold to an 8" mold are much more experienced, so they know what a well-knitted and adequately-pressed cheese looks and feels like.)

I think it's pounds per cubic inch that has to be the crucial measure. 
Title: Re: Mould size & pressure
Post by: Cartierusm on February 03, 2009, 09:13:25 PM
I've done the calculations and Pounds per cubic inch when factored from a pressed 2# cheese that comes out 4" wide by 4" high is not far off from the bigger batches and bigger molds. I don't know if it's that necessary. I think in the end pressure guide lines are just that GUIDE lines. When you move up to bigger wheels only experience will come into play because you need to consider more than just curd knitting, but final moisture content.
Title: Re: Mould size & pressure
Post by: wharris on February 03, 2009, 09:35:52 PM
Repost from the other forum:

I do agree that thickness of the mould plays a part.  I will also say that the type of cheese plays a part.

I do not argue that whatsoever.

I was merely talking about adjusting canned recipes in order to maintain a constant pressure across different wheel sizes.

So for example, if you had a 4” wheel that is 3” deep, and a 10” wheel, that is also 3” deep, the surface area increases from 12.4si to 78.5si.  In order to maintain a constant pressure (a specific psi) on your wheel, you will need to increase the force (weight).

While there may a relationship between cheese volume and surface area, I am not sure how they are linked. 

In the case above, the volume of cheese increased from 37.5cuin in the 4" wheel to 235.5cuin in the 10" wheel. But I am not sure that an increase in PSI is warrented because the depth of the cheese curds remains constant in both moulds. Both are 3" deep.    Keep in mind that in order to keep the pressure constant on both wheels, you will need more weight on the larger wheel due that weight being distributed over more square inches of cheese.

However, if the same 4” mould had 10” of curd instead of 3” of curd, I would understand if more weight was required to properly press that wheel.  It seems reasonable to assume that the deeper the curd, the more resistance to pressure the cheese would be.

I think that is one reason that the commercial horizontal presses have followers every 15 inches or so, instead of one long press. 

So while cubic inches are relevant, I'm not sure how.

But then again, that is why i am here,  I want to hear from the pros.. 

We need Quinlan to "weigh in"  on this topic.


Title: Re: Mould size & pressure
Post by: Cartierusm on February 04, 2009, 12:27:50 AM
Qunilan's been MIA, probably because his cheese making season is over.

P.S. I might go to one of the Cheese Making Conferences in Sonoma I've talked to the coordiantor and got an outline of events. I only need to go for one day and it's $85.
Title: Re: Mould size & pressure
Post by: wharris on February 04, 2009, 12:35:30 AM
I hope you do. 

We are all expecting a full report!
Title: Re: Mould size & pressure
Post by: Cartierusm on February 04, 2009, 12:43:44 AM
Thanks wayne, it might be a while as I'm trying to perfect some other things first. I can't wait until I get the mesh in.