From the HBD Archive
From: Martin A. Lodahl <pbmoss!mal@hplabs.HP.COM>
Subject: Attenuative Yeasts
Date: 1989-08-30 16:18:27 GMT

In HBD 241, Patrick Stirling asks (concerning yeasts):

> What's 'attenuative'? Sounds like it's the speed with which
> a yeast does its job and goes dormant ...

Aha! Had you read Miller instead of Papazian, ... 8-> 8->

"Attenuation" refers to the degree to which wort sugars are used by
the yeast. Red Star Ale yeast, for example, munches merrily on
simple and duplex sugars, but has little appetite for the more
complex sugars. Edme will tackle the triple sugars as well. I've
only once tried a semi-controlled experiment where I made two
successive batches, varying only the yeast (first Red Star, then
Edme). I say "semi-controlled", because temperature during
fermentation and fining was essentially uncontrolled, and though the
weather was essentially the same (hotter than the hubs of Hell) for
both batches, there may have been a significant variable introduced
there. The Edme yeast (considered more attenuative by Miller)
produced a much drier brew (too dry, in fact, for my tastes), but
with fewer initial flaws. Both resolved well, the Red Star batch in
about 5 weeks and the Edme batch in about 3, with the Red Star batch
always sweeter, fruitier, and with more of the famous banana esters.
The sweetness, in particular, I attribute to the difference in
attenuation between the two yeasts.

> On another tack, what do you think of using ice to cool wort?

I've had only good luck with this method, but I'm still at
partial-mash brewer. When I've got my BIG kettle so I can boil the
whole volume of wort (anyone know a good source for 33-quart
enameled steel canning kettles? Can't seem to find one here), I
won't have ice-dilution as an option any more, alas.

= Martin A. Lodahl Pac*Bell Minicomputer Operations Support Staff =
= pacbell!pbmoss!mal -or- mal@pbmoss.Pacbell.COM 916.972.4821 =
= If it's good for ancient Druids, runnin' nekkid through the wuids, =
= Drinkin' strange fermented fluids, it's good enough for me! 8-) =


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