« on: October 09, 2012, 08:59:12 AM »
Look at the Berliner Weiss presentation from the NHC 2012, which can be found at http://www.homebrewersassociation.org/pages/lets-brew/homebrewing-seminars/2012
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According to this paper, http://www.fermentis.com/SHARED/Doc_52528.pdf, the amount of dry yeast per gram on average greatly exceeds the 6 billion cells per gram. That's probably the discrepancy.
S-04, for some reason, only has 8b per gram, according to that. I've always used the 20b / gram rule of thumb, but I guess it makes sense that it may vary by strain, and I'll try to use that info in the future.
On the time scale of things, how long does it take for the CO2+H2O -> H2CO3 to be 50% towards equilibrium? I see the kintetic constants, but don't know how to use them since I have not dabbled in reaction kinetics yet since there was no need so far.
Are we talking seconds, minutes days or weeks here?
I agree that if only 2% of the dissolved CO2 is in a carbonate form then it would be hard for me to imagine that fine carbonation could be explained solely by the slow dehydration of carbonic acid. I believe that with [HCO3-] being the dominant form of carbonate in beer that carbonates could reversibly react with metals, sugars, protein, alcohol etc. as alluded to by Brungard.
That would allow us to create 10 times more (H2CO3 +HCO3-) from the dissolved CO2. But that reduces the dissolved CO2 by 2% instead of 0.2% which may not be enough to explain this effect.
kamerog mentions bicarbonate (HCO3-). the relation between H2CO3 and HCO3- is determined by pH of the solution and at beer pH (~4.3) the vast majority of the carbo species will be H2CO3. So we are stuck here.
Don't worry, the chrome is in metallic form and unless you see corrosion there shouldn't be any significant chromium dissolving. Theres chrome in stainless steel too for that matter. Chromium is actually an essential nutrient, albeit at low levels.
Are you saying it always boils over when you FWH?Add some hops before the boil to avoid a boilover. That is a good tip from Greg Noonan's Brewing Lager Beer.
Has that worked for you? I've FWH dozens, maybe hundreds, of batches and I've never seen it prevent a boilover.
I noticed that the wort is less prone to boil over when hops are added before the boil starts. It doesn't prevent boil-overs, but it my experience it makes it easier to control them.