sweet....I love complications....see this is lesson one really...all I had ever learned was...well...that homebrewing can be done....I always wondered why everyone made the dark stuff right away....
Physics question very unrelated to diving
- Thread starter dlwalke
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sweet....I love complications....see this is lesson one really...all I had ever learned was...well...that homebrewing can be done....I always wondered why everyone made the dark stuff right away....
I believe that temperature has something to do with making espresso. Espresso can not live by pressure alone
RichLockyer
Guest
Ah, but don't forget the P,V,T relationship:jbd once bubbled...
I believe that temperature has something to do with making espresso. Espresso can not live by pressure alone
P1/T1 = P2/T2
V1/T1 = V2/T2
Hmm... lacking heat, pressure can substitute... have we found yet another use for a Spare Air?
but releasing pressure from a Spare Air would result in a decrease in the temperature. Not to mention the coffee grounds would probably going flying like dust in Kansas tornado
manoof
New
First off, in the case of espresso machines pressure isn't controlled by temperature, it is controlled by the impedance of the grounds to steam (otherwise it just goes off into the atmosphere). Because of this, V is not constant, you have a semi-permiable membrane (the grounds) at one end of the system, which releases steam (and pressure) at a rate which is proportional to the pressure (as well as the fineness and density of the grounds).
Spinning might help compress the grounds, but won't really impact the steam, not being a coherant body, and therefore subject to "interesting" rules regarding centripical force (figuring intertia etc. in.... it's just not worth thinking about). Oh, and you can't instantly raise the pressure of water three fold very easily.
An easier solution is to force the steam through a narrower tube (going back to P=F/A), which is long enough to accomodate the same volume of grounds. Now the drawback to this is that if you're just heating this contraption over a stove or something, the steam is going to cool and condense as it's being forced upwards though this long narrow tube, and come back into the pot of water (wait does this sound like a perk?).
So to pull this off, you need to get a long narrow tube of coffee grounds, mount it on an air-tight piston assembly over a large resevoir, fill the resevoir maybe 1/3 fulll of water, get a nice rolling boil going, and then jam the piston down *hard* (an industral hydralic press may help here). Voila, instant pressure, sufficient resistance from a long (well packed) tube o' grounds, and high quality, 3 atm+ espresso flying everywhere from the top of the tube.
Either that, or just stuff a pump on the front end of the espresso machine (like all the commercial models have), and keep pumping water/steam into the grounds to raise the pressure.
Ack, first post to a diving board, and I'm discussing fluid dynamics... .
maybe it is time to go stick my head underwater again.
Spinning might help compress the grounds, but won't really impact the steam, not being a coherant body, and therefore subject to "interesting" rules regarding centripical force (figuring intertia etc. in.... it's just not worth thinking about). Oh, and you can't instantly raise the pressure of water three fold very easily.
An easier solution is to force the steam through a narrower tube (going back to P=F/A), which is long enough to accomodate the same volume of grounds. Now the drawback to this is that if you're just heating this contraption over a stove or something, the steam is going to cool and condense as it's being forced upwards though this long narrow tube, and come back into the pot of water (wait does this sound like a perk?).
So to pull this off, you need to get a long narrow tube of coffee grounds, mount it on an air-tight piston assembly over a large resevoir, fill the resevoir maybe 1/3 fulll of water, get a nice rolling boil going, and then jam the piston down *hard* (an industral hydralic press may help here). Voila, instant pressure, sufficient resistance from a long (well packed) tube o' grounds, and high quality, 3 atm+ espresso flying everywhere from the top of the tube.
Either that, or just stuff a pump on the front end of the espresso machine (like all the commercial models have), and keep pumping water/steam into the grounds to raise the pressure.
Ack, first post to a diving board, and I'm discussing fluid dynamics... .
maybe it is time to go stick my head underwater again.