On Tue, 17 Jun 2003 16:04:32 +0200 Sterrenkijker sputtered the following meaningless banter:
I'm very familiar with that problem of yours..
>The answer is simple:
>-your fermentation was too vigorous. This means the temperature of the
>fermenting wort was too high. As I mentioned before many times in this
>newsgroup: set the temperature of the wort in the primary as low as
>possible. I see that you have a fridge which can be set at 65 °F (18.3
>°C).. Well, I guess that in your case that temperature would be the
>right one for fermentation! Should primary fermentation with you even
>work at a few degrees less then all the better!!
>-you wrote you kept the secondary during 12 days at 65 °F. Wrong!! You
>should have kept the secondary lower than 50 °F. I keep the secondary
>even at lower temperatures (39 - 42 °F).
WRONG! That is personal taste/preference. I have fermented much higher and secondaried way longer at way warmer temps than that, with no ill effects ever. One batch did go bad, but that was traced back to sanitation, as are most problems, not heat. Heat will produce a lot of off flavors and fusel oils though. Good try.
Your beer has been infected by mildew bacteria (acetic acid bacteria).
>That's a kind of wild yeast only suitable for making sherry or
>vinegar. So you got an acetic fermentation. This kind of infection is
>typical with homebrewing during summer. Your beer is ready for pouring
>it into the sink. That plastic bag in top of the carboy was not
>responsible. Next time be a little more cautious and keep everything
>cool. You won't regret. I'm doing all grain for over 5 years now and
>even I still have troubles with that phenomenon from time to time (I
>know that I have to change my style of brewing when the hot days come
>but I am so forgetful).
His batch may be far gone, but it was not the temp that did it. It was definitely the bag. There is no way you are going to keep out any bacteria just by putting a bag on it. The warm temp mixed with the bag helped promote it, because of the bacteria that like to harbor themselves in the fridge.
If you get the chance to visit a professional micro brewery then
>you'll notice that it is in fact a complete cold store. Remember
>Pasteur. There is a reason why.
>The best arms against acetic acid bacteria are cold and keeping the
>wort free of air after fermentation.
>Many handbooks on homebrewing don't say anything about the importance
>of cooling. In my eyes they are all just good book sellers but no >brewers.
>
>Regards,
>
>Norbert (from Flanders, Belgium)
Pasteur also used heat to fend off the nasties, don't forget that. Cooling down to below 50 will not kill off the bacteria anyway, freezing for a prolonged time will help but will also do not better than pasteurization, or pressure cooking. But you would not want to do that with your beer. And as far as secondary at those low a temp, you will not get the desired flavors in an ale at that low a temp. The recommendations are there for a reason.
-Riggs