Author Topic: Commercial Gouda press  (Read 5652 times)

Offline mightyMouse.tar.gz

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Re: Commercial Gouda press
« Reply #45 on: November 04, 2012, 08:47:22 PM »
A cheese for your persistence!

He he, someone noticed my stubborn... uh, I mean persistence!
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try { Cheese myCheese = new Gouda(); } catch (NastyCheeseException e) { throw new CultureContaminationException(); }

Offline H-K-J

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Re: Commercial Gouda press
« Reply #46 on: November 05, 2012, 08:23:30 AM »
I think I am gettin a headache :o
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Offline bbracken677

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Re: Commercial Gouda press
« Reply #47 on: November 05, 2012, 09:14:04 AM »
I think I am gettin a headache :o

LOL  we have gone way out there!

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Offline Alpkäserei

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Re: Commercial Gouda press
« Reply #48 on: November 05, 2012, 05:00:25 PM »
When pressing cheese, there is a latency. This is obvious, and we seem to agree on this. It takes time for the pressure in a cheese to resolve itself to the point where the weight will pass straight through unhindered into the next cheese in the stack.

But it seems to me that this takes longer than maybe we think it should. Like I said, I have pressed cheeses before in a stack, and can attest that the difference in pressing quality by location is obvious. Rotating is necessary. This can only mean that the theorizing and calculating is leaving out something very important. My guess, though I may be wrong, is that the latency factor is greater than we are giving it credit. It is kind of like the freight train analogy, we have to wait for all of the couplers to pull tight before the last car will move. But it is like a very very slow freight train, just creeping along.

In the early pressing stages, the amount of time the cheese is under the press does not seem to be long enough to arrive at equilibrium. Either that, or the proportion of time spent at equilibrium relative to unbalance is too small, resulting in inconsistent forming throughout the stack. There are 2 solutions to this problem. The obvious solution is to leave the cheese in the press longer. The only problem with this is that it results in an imbalance of the material within the cheese (certain compounds will want to make their way to the bottom, particularly during the early stages of pressing) and a poorly formed exterior (most surface imperfections need to be eliminated during the first hour or two of pressing, after this they are extremely difficult to erase)
The better solution is just to use a series of short early pressings with flipping and rotation between each one. It is a little more work, but yields ideal results
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Offline Mike Richards

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Re: Commercial Gouda press
« Reply #49 on: November 06, 2012, 03:48:44 AM »
Alpkaserei--have you seen this in both horizontal presses and vertical presses or just vertical presses?  I don't mind my analysis being incomplete--and it clearly is if reality doesn't behave the way my analysis describes it should (or I could have just made a mistake...).

I don't like the train example because the delay in the force reaching the last car is due to the distance required to travel before engaging each successive car.  When pressing a stack of cheeses (I assume, because I've never used a horizontal press) the cheeses are not left with any distance between (and, I suppose, if they were, the time required to engage all of the cheeses wouldn't count in the pressing time).

A better model, perhaps, is that of a spring and damper.  Most people are familiar with a spring (though they often have misconceptions about how they work...).  A damper is usually described as a piston, with holes in it, held within a sealed cylinder that is filled with some fluid.  When the piston is pushed, it travels through the cylinder, forcing the fluid to travel through the holes in the piston from one side of the cylinder to the other side.  Many automobile shocks contain dampeners and they are often found on doors to prevent them from slamming shut.  If the holes are large and the fluid has low viscosity (it's runny) then you can apply a great deal of force to the piston, and only supply a small deal of force in the opposite direction to the cylinder to prevent the cylinder from moving.  If the viscosity is high and the holes are small, most of the force that is applied to the piston will need to be applied to the cylinder in the opposite direction to prevent the cylinder from moving.  In both cases, the piston moves.  Regardless of the size of the dampening coefficient (how much damping the damper does), once the piston has reached the end of its travel, all force applied to the piston is transmitted directly to the cylinder.

If we go back to the cheese now, we can model it as a spring-damper system in series--that is, the cheese press pushes on the damper of the first cheese, which then pushes on the spring of the first cheese, which pushes on the damper of the second cheese, which pushes on the spring of the second cheese, etc.  If you imagined having a uniform mixture of curds and whey where the ratio of whey to curds was sufficient to prevent the curds from touching each other, this model would be pretty good.  Instead of  the classical dampener, we've left the piston (the follower) hole-free, and filled the cylinder (the mold) with holes.  As we press on the "cheese" the whey leaves the cylinder, damping the force of the piston.  In this case, we'd expect to see a lot of whey coming from the first few cheeses and very little, if any, coming from the last few for the first while of pressing.  In this model practically all of the whey would be pressed out before the curd started to knit (because the springs, the curd, wouldn't have to carry much load until all the dampers were completely bottomed out).

A better model, in my estimation, is that of a spring-damper system in parallel--that is, the press pushes on both the damper and the spring of the first cheese at the same time.  These two from the first cheese, then push on the spring and damper of the second cheese, and so forth.  In this model we can think of the curds as the spring and the whey in the mold as the damper.  When a force is applied by the press, a portion of it is supported by the spring--this portion of the force is transmitted directly to the next cheese (and through all of the cheeses).  The remaining portion of the force is carried by the damper.  How large this portion is and how much of it is transmitted to the next cheese depends on the characteristics of the damper.  If the spring is really weak, and the damper has a low damping coefficient (lots of holes and a non-viscous fluid), then we'd expect to see a similar phenomenon as we saw in the previous case--a lot of whey coming from the first few cheeses and very little (though a bit more) from the last few.  If the springs were not weak, and the damping coefficient high, we'd expect to see a more uniform loss of whey, though the first cheeses would still lose a little more than the last.

What might be the most accurate model would be to combine these two models.  The whey can be modeled as a damper, but the curd itself, if drained well, for example, is probably well modeled as a spring-damper system (though it probably is more like one in parallel than in series).  In this case, the whey has one damping coefficient (probably relatively small) and the curd's damper has a different damping coefficient (probably a lot higher).  If I recall correctly, you can combine the two dampers into an "effective" damper and you end up with a model like the second model, where the damping coefficient is somewhere in between that of the curd's and that of the whey's.

The relative intensity of pressure (or the force) experienced by the last cheese, when compared to the first cheese, depends on the stiffness of the spring (or the stiffness of the curd) and the damping coefficient of the whey/curd damper.  If the curd is very stiff, regardless of the damping coefficient, the difference in pressure experienced will be small, if the damping coefficient is large, regardless of the stiffness of the spring, the difference in pressure will also be small, however if the curd is not stiff and the damping coefficient is small, the difference will be large.  Of course, if things are more moderate, the difference will, too, be moderate.

Now, how to measure the damping coefficient and stiffness of cheese during pressing.

And despite writing all of this boring stuff at 0200 in the morning, I still don't know if I can go to sleep.  Curse this dumb cold...
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Offline Boofer

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Re: Commercial Gouda press
« Reply #50 on: November 06, 2012, 08:39:11 AM »
Thanks, Mike, I was just...ZZzzzzz....  :)

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Offline H-K-J

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Re: Commercial Gouda press
« Reply #51 on: November 06, 2012, 09:12:52 AM »
LOL ;)
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Online smolt1

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Re: Commercial Gouda press
« Reply #52 on: November 06, 2012, 11:43:15 AM »
What happens to the curds and whey inside the mold as it is pressed is very complicated and is NOT a physics problem BUT. The forces on each mold in a horizontal or vertical stack is a physics problem and there are some truisms.

1 The cheese in a given mold will not " know " if what is pushing on its follower is another cheese mold, a spring or a long stick, or anything else. It will only " know " that it is a force of a certain magnitude.

2 The process of compression is 99.9 to 100 percent STATIC( very slow and very small movement). So any work done( and resulting change in energy) is almost 0. Once the cheese is fully pressed it is 0.

3 If you put a scale between each mold in a vertical stack and read the force(weight) on each scale, you will see that any mold in the stack has a force (weight) on it equal to the weight of all the molds above it plus the force(weight) applied to the top mold by the press.This is true( 99.99999%) at the start of pressing and( 100 %) at the end of pressing.

The components of the solution to a problem have to be separated to get an answer. For instance ,if I push on a giant oak tree for 10 minutes I have expended a lot of energy( I am sweating) BUT I have done no work to the oak tree( it didn't move)

Offline Mike Richards

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Re: Commercial Gouda press
« Reply #53 on: November 06, 2012, 07:16:35 PM »
Thanks, Boofer.  I'm glad it helped put someone to sleep.  And, since I mentioned it and I know you all care, the "cold" that was keeping me awake turned out today to be strep throat.  No work for me tomorrow--for some reason the rest of the folks I work with don't want to get strep.

Smolt--I thought everything was a physics problem... ???
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Offline mightyMouse.tar.gz

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Re: Commercial Gouda press
« Reply #54 on: November 06, 2012, 07:26:18 PM »
What happens to the curds and whey inside the mold as it is pressed is very complicated and is NOT a physics problem BUT. The forces on each mold in a horizontal or vertical stack is a physics problem and there are some truisms.

Why do you say this is not a physics problem? Sure, only the most sadistic of professors would choose this as a final exam question, but there are forces and energies and all kinds of good stuff involved. (Hmmmm.... I wonder if we could get a paper out of this... One of those novelty papers you see in the AMS Bulletin or Physics Today.)
// bad cheese exception handling
try { Cheese myCheese = new Gouda(); } catch (NastyCheeseException e) { throw new CultureContaminationException(); }

Offline mightyMouse.tar.gz

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Re: Commercial Gouda press
« Reply #55 on: November 06, 2012, 07:27:21 PM »
No work for me tomorrow--for some reason the rest of the folks I work with don't want to get strep.

Wusses! I swear, you never know who your true friends are till you have strep throat do you!
// bad cheese exception handling
try { Cheese myCheese = new Gouda(); } catch (NastyCheeseException e) { throw new CultureContaminationException(); }

Offline Alpkäserei

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Re: Commercial Gouda press
« Reply #56 on: November 06, 2012, 08:43:06 PM »
Smolt, do you have observed proof of what you say? Because I have observed proof to the contrary.

When I put multiple cheeses in a vertical stack, the top cheese releases a great deal of whey, while the bottom cheese releases very little. Yes, I could leave them in longer until the forces equalize but this is bad practice. The turnings need to follow a regular time schedule for good rind formation.

We all know that it makes no difference to the cheese where the forces come from that are affecting it, but does that mean we can't ask what is going on? Sure, it doesn't actually get us anywhere but who cares? It's enjoyable to look into the physics of a problem and figure out what is going on.

Mike I think you have a pretty good understanding of the situation. I suspect that the damper illustration might be getting close to the reality.

Also another thing to consider, some work goes into compression resulting in heat. Other work goes into a chemical process going on in the curd that causes the cheese to fuse together. The goal of pressing hard cheeses, at least in my experience, is to cause a fundamental change in the makeup of the cheese. We can observe this when we compare a pressed alpine cheese with a Parmiggiano Reggiano. The parm is not pressed, and the structure of the inside is radically different than that of my Alpkäse even though the make procedure is almost identical up to this point.

It takes energy to cause this to happen, a significant force applied directly to the cheese causing the curd to 'knit'. This requires heat and a compressive force to happen. We can observe that an increase in one or both of these factors results in a quicker, more complete knit while a decrease has the revers effect.

Furthermore, the internal structure of a pressed cheese in changed in more ways than just being more compact. There is a obvious difference in texture. I submit that the act of applying a great deal of compressive force to the cheese results in a fundamental change of the structure of the cheese -i.e. a chemical reaction. This reaction by necessity uses supplied energy to happen. The result of this would be a reduced force over the span, would it not?

This helps to explain a few things about pressing, such as why it is so important to keep the cheese warm, why it is important that the proper pressure be applied, etc.

Just some thought, probably some errors in there.
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Offline Mike Richards

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Re: Commercial Gouda press
« Reply #57 on: November 07, 2012, 10:09:36 AM »
This has been a fun discussion.  It seems time to do some experiments.  Here are a couple I propose--if you think they will fail to elicit an answer to the topic at hand, let me know.

If a stack of cheeses will, regardless of the mechanism, reduce the load (force) that is transmitted from that applied by the press on the first cheese to that experienced by the last cheese, then we would expect to see a reduction of load across a single cheese as well.  Agreed?  Then, I propose that everyone, during there next cheese make, put a scale under the cheese (perhaps cover it in plastic wrap or something...) and measure whether or not the actual force the scale weighs is less than the force applied by the press.  If you've got two scales, you could put one between the press and the follower and one between the cheese mold and the base of the press.  In both cases, unless you press horizontally, you'll need to subtract the weight of the cheese, mold, follower, (and additional scale if using two) from the lower scales reading.

If someone with a multi-cheese press is willing to play, their result would be even more convincing--they could do it with 2 scales as well, 1 between the press and the follower of the first cheese, and one between the last cheese and the base of the press.  Again in a vertical setup, they would need to subtract the weight of all the cheese, molds, etc. from the lower scales reading.

If there is a reduction of load, then we know the cheese is behaving more like a damper than many of us could have imagined (me included in this--despite my long boring discussion of how to model the cheeses, I really expect almost no difference, but like I said, I don't mind being wrong).  If the loads are the same, then we know the cheese acts a lot more like a spring.  If there is an increase in load, we'll know we've broken the laws of nature, and we can be even more impressed with awesomeness of cheese.  ;)

I'll see if I can make this happen on my next cheese--though the scale we have that would work for this (a bathroom scale) isn't exactly trustworthy...  It would be a lot more interesting to have more people participating and reporting their results.

Let me know if you're in.
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Offline bbracken677

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Re: Commercial Gouda press
« Reply #58 on: November 07, 2012, 10:17:24 AM »
This has been a fun discussion.  It seems time to do some experiments.  Here are a couple I propose--if you think they will fail to elicit an answer to the topic at hand, let me know.

  Then, I propose that everyone, during there next cheese make, put a scale under the cheese (perhaps cover it in plastic wrap or something...) and measure whether or not the actual force the scale weighs is less than the force applied by the press.  If you've got two scales, you could put one between the press and the follower and one between the cheese mold and the base of the press.  In both cases, unless you press horizontally, you'll need to subtract the weight of the cheese, mold, follower, (and additional scale if using two) from the lower scales reading.



Let me know if you're in.

The main problem with the single mold press trial is that the difference is likely small enough to be measurable only by very accurate equipment....

I will be checking for an increase in temp the next time I make a cheddar and push the press to it's limit...I am hoping that perhaps the change in temp will be measurable. I think that a multiple mold pressing would, perhaps, yield a measurable difference.

Offline H-K-J

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Re: Commercial Gouda press
« Reply #59 on: November 07, 2012, 10:51:33 AM »
I was going to wright something important here but I got a brain cramp :o
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