Kennet Boater wrote: > Hi all, > > After a discussion about coffee makers last night I am left with a > question which the more scientifically minded can possibly help with. > > My friend says that in his home country of portugal he can buy a > coffee machine that heats the water to 150'c. > > Now I always thought that water only ever got to about 92'c (or there > abouts I can't remember the actual number) and then turned to steam. > The more heat you put into the water after that temp the faster the > steam is produced hence 'rapid' boil. roling boil. simmer' etc. > > Can any one clarify as to what temp water will get to before it turns > to steam (boiling point) and if you can get water to 150'c and remain > in its water state not turning to steam. > > I'm sure you'd burn your mouth if you drank coffee at 150'c any way. > Im going to stick to my stove top espresso machine! Lovley!!!!
<santa mode on> Ho, ho, ho, ho, ho, ho, ho <santa mode off> Not a hope in hell of getting 150C - my guess is he's got some US device and it's 150F... That temp requires 54psig to prevent boiling. Not going to happen in a domestic device. Water boils at 100C, not 92C. Just put the lid on the saucepan! Water needs 4.18 joules to raise the temperature of 1g by 1C, it needs 2300 Joules to boil off 1g. If the lid is off there is a lot of cooling by evaporation. Ron Jones Process Safety & Development Specialist Don't repeat history, unreported chemical lab/plant near misses at http://www.crhf.org.uk Only two things are certain: The universe and human stupidity; and I'm not certain about the universe. ~ Albert Einstein
