Oh you’re right Tom, the spring analogy was a bad. I said so at the time.
Incompressible solid fluid liquids are complicated things ... waaaayyy beyond me.

newbie - 27 February 2009 12:13 AM

So, where have we got too? Nowhere?
As I stated at the beginning of this thread there is something horribly wrong with the way we work out these pressures, it defies basic physics.

A military saying goes ‘bullshit baffles brains’ so lets concentrate on the basics. Lets forget all the fancy talk of Psi, pressure, lbs per,and all the other emotive stuff which gets bandied about when this subject comes up and consider the following.

If you apply force in a downward fashion to say a disc of 4” in diameter, then apply the same force over a lager area, lets say 5 feet in diameter. The way things stand at the moment means you would have to step the pressure up by thousands of percent to achieve the same result? Totally ridiculous. Downward pressure on a disc is the same at the center as it is at the edge, there is no need to increase the pressure to account for a wider disc.

Now take a second scenario. We have a tube with 4” of material inside, applying pressure to the top will need X pressure to compress it. Now increase the contents by 2, this will lead to a necessary pressure increase of 2X to achieve the same amount of compression.

With this in mind, the only time we need to increase the pressure would be by increasing the depth of the mould.

In practical terms. Using the same mould say 6” with 2 gallons it would be one pressure, increase that to 4 gallons and then you would need to increase the pressure.

So, I believe my hypothesis to be correct, “there is something wrong” with the present position on pressure.

Newbie, you are scientifically wrong…

Pressure is force on surface area, so it is weight on surface

If you increased the disk size (diameter) this means u increased the surface, so the weight has distributed on bigger surface and the pressure decreases.
amount of cheese inside the cylinder is not related to pressure, so in 4” mold with 20pounds wight on top is same pressure if u put inside it 1 pound cheese or 4 pound cheese, all it counts is the surface area under the press disk.

braufrau - 28 February 2009 09:35 PM

newbie - 27 February 2009 12:13 AM

You have made two hypotheses.

1) increasing area does not require increased force (weight)
2) increasing height requires increased force.

#1 is wrong.
#2 is correct.

 

#2 it is not correct:  because the vertical hight is parallel to the vertical force axe,  so it’s contribute to increase more pressure by it’s self.

example: you (whatever ur hight is) weight X and when u walk on the snow with your shoes, u r applying your weight (force) on you feet area , and the result pressure wich cause your foot to sink Y centimeters.
Now, same u (same weight same hight), but u are wearing flat big plates , the result is that u made less pressure (distributed on big shoe surface) and u will sink a lot less into the snow…..

Over and out

Well spoken, and a good analogy!

Ok, OK, I surrender. Actually the snow shoe analogy is a good one. I should have thought of that as I often walk in the woods on my snowshoes.
It still does not explain how I can get good knitting cheese with considerably less pressure than you guys are talking about.
For example, two Parmesans in a row at only 15 lbs and yesterday a Pepper Jack at 20lbs all in a 6 inch mould. A perfect rind everytime with absolutely no blemishes.

Newbie .... for my experience , parmasan and swiss (maximum 40# at final stage for 7” mold) does not need a lot to knit , but cheddar does

Well I’ll find out later today, as I intend to make a Liecester.

newbie - 01 March 2009 02:13 PM

Well I’ll find out later today, as I intend to make a Liecester.

good luck, take into concidration, it is all related how hard is ur curds, if u salt ur curds before press u need more force (and type of cheese is hard) and if u curds are hot and tender and u will brine later , then u need less force…

mine, traditional cheddar, on final press stage i hardly manage to get close rind for my 6” mold with 100lb !!!
mine, swiss , on final press stage for 6” mold i use 40 lb only and u can use less

Good luck and have fun with the Leicester.  Its a great cheese!!