On Wed, Apr 21, 2004 at 11:08:12PM +0200, JAKM (Jakob Mortensen) wrote: > Jeg melder mig på banen til at lave et lille forsøg.
Always nice to see that people want to do their own experiments, instead of (mis?)quoting some "authoritive" website! Jeg har udtænkt følgende: > > 1. Man laver en sukkerblanding af almindeligt hvidt (fuldt forgærbart) > sukker og vand. Lad os sige 12g pr. liter. Det skulle give en CO2 > volumen på 3. > 2. Man tilsætter en slat gær (f.eks. fra sit sidste bryg) og hælder > blandingen på en alm. flaske. > 3. Man borer et hul i en kapsel og > monterer en møtrik og en gummipakning på bagsiden af den med en klat > lim. > 4. Man monterer kapslen og skruer et manometer fast i møtrikken under > kapslen med endnu en gummipakning imellem. > 5. Efter at den har gæret færdig vil man kunne aflæse trykket i bar på > manometeret. Hvis man deler dette med 3 får man hvilket tryk 1 volumen > CO2 giver). > > Jeg har de nødvendige dele så jeg får lige bikset noget sammen og > vender tilbage når der er resultater. I don't want to spoil anything, but I have a strong feeling that the resulting pressure depends on the amount of airspace in the bottle. Of course your experiment would be reasonably valid for "typical" airspaces, but to be scientific, you should repeat the experiment with different airspaces (say 1cm, 3cm, and half a bottle). (and do mount some sort of overpressure release, so the experiment won't kill you!) If all the Co2 would stay as gas, we would have a simple case of adding more and more Co2 to the same volume, thus increasing the pressure (temperature being held constant). The smaller volume, the higher pressure, of course. Unfortunately, the calculation is not that simple, because some (most?) of the CO2 will dissolve in the beer. (To keep it simple, we can assume it to be water...) I do not know enough physics or chemistry to say how the solubility of Co2 in water depends on the pressure, but I am pretty sure that it does, somehow. If someone here can explain more about the solubility of Co2 in water (and/or in water mixed with (say) 5% of alcohol), I would like to hear. Still, I am curious to hear any results! - Heikki -- Heikki Levanto "In Murphy We Turst" heikki (at) lsd (dot) dk
