- Some new things I've just read / forgotten stuff revised, that you might
find useful ....
1) yeast produces 33 times more alcohol while reproducing than when resting
(so most of the gains are in the first couple of days, then you're just
relying on the large numbers of yeast finally present to slowly work their
way through the remaining sugars)
2) you end up with about 2g per litre of yeast (eg 40g in a 20L wash) This
is why you don't get the full 51.1% conversion of sugar to ethanol, and
gives some idea of the amount of nutrients - particularly nitrogen - that
you need to supply.
3) fusel oil concentration in the wash can be up to around 0.24 g per Litre
from 20% sugar (eg about 3.2 mL from a 20L wash)
4) fusels increase depending on ...
* yeast strain (eg Saccharomysce cerevisia makes more than
* temperature (higher temp = more fusels)
* increased aeration and agitation (news to me ! so don't over-stirr
* wort composition (nitrogen sources and readily metabolised sugars)
5) the most common limiting factor for yeast growth is a lack of nitrogen.
Nitrogen is approx 9% of the cell mass. Most common form to add it is as
the ammonium ion, as the sulphate and phosphate salts (phosphorus is
approx 1-2% of the cell mass, and sulfur 0.3-0.5% so these are needed too -
this is a nice way of getting all three in there)
6) the second most common limiting factor is a lack of oxygen, but it only
needs it until high cell numbers are present (eg during the first day) (so
make sure that you've aerated the wash well just prior to adding the yeast,
but don't do this too much later in the game) "Splash filling" is enough
to do the job.
7) bacteria can double in number every 20-30 minutes, but yeast takes 3
hours (so guess which one will win the race if an infection gets started
and you don't deal to it)
- --- In Distillers@y..., Tony & Elle Ackland <Tony.Ackland@c...> wrote:
> Some new things I've just read / forgotten stuff revised, that youmight
> find useful ....Wow! Too right it was useful stuff. You amaze me with the amount you
know on this subject, but it's nice to know there's still things to
learn, or re-learn.
More power to your elbow!