From the HBD Archive
From: ileaf!io!peoria!cjh@EDDIE.MIT.EDU (Chip Hitchcock)
Subject: stuck fermentations
Date: 1990-05-08 10:48:38 GMT

I recently had serious fermentation start up in some bottles and am
wondering whether there was any way I could have persuaded it to happen
in the carboy.
The recipe was from Papazian's Sparrowhawk Porter with available
ingredients---1 John Bull dark, 1 M&F Amber, 1# dry amber, 1# chocolate malt,
2.5 oz hops (boil+finish), 5 gallons water. There was no action for three
days after pitching; this may have been poor yeast (I'm just now learning
about rehydration) or may have been the irregular room heating---temperature
in the carboy had fallen from 76F to 63F. I pitched another packet of yeast
and brought in a space heater. In a day the temp was in the low 70's; I got
vigorous fermentation for 2 days, then nothing. SG had dropped from 67 to 32;
I was expecting (from the recipe) somewhat lower so I stirred up the yeast
sediment (per suggestion of local homebrew shop). 10 days later there had
been no action (bubbles, dropping SG) whatsoever, so I bottled with the
canonical 3/4 cup of corn sugar.
The beer was harsh but drinkable 2 weeks after bottling and mellowed a bit
as it aged. I had a few bottles in the office for ~6 weeks, then noticed that
all the caps had everted (my capper is the Italian model that makes a dimple
in caps on longneck bottles). It took about 5 minutes of careful bleeding in
a sink before I could take the cap off without a geyser. I chilled and
opened a second bottle; after it had subsided and warmed up I got an SG of
1.023.
I'm not too worried about the bottles I have left in the cellar, but but
I'd really prefer to eat up all the fermentable sugars in the carboy (and be
able to bring samples in for other homebrewers without worrying about
explosions). Is there any way to test for remaining sugar, or to persuade the
yeast to finish its job?
- When I pitched the yeast I aerated the wort by sloshing the carboy around
until there was a vortex in the middle, then reversing direction until the
vortex reversed---is a paint stirrer or an aquarium bubbler necessary for the
heavier batches?
- Is it better to keep the fermenting temperature in the high 60's in hope
the yeast will grow slower but sturdier?
- Is it worthwhile to take off some (possibly unfinished) brew,
boil to sterilize, and see whether it will activate new yeast (could spend a
lot of yeast that way...)?
- The office was probably 65-75F most of the time---yes, that's not the best
keeping (or drinking) temperature, but I wouldn't expect it to jump-start
yeast that had shut down at that temperature.
- I don't \think/ a wild strain could have gotten in and eaten some of the
sugars the packaged yeast gave up on; everything I worked with was thoroughly
sanitized (1/4-1/2 cup bleach in 6 gallons water)---the bottles were cleaned
\twice/ because I discovered while they were drying that my filler had vanished
(it took a day to get a replacement, and I wasn't sure I could use bottles
that had been sterilized the day before).

Any ideas? Any suggestions?

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