ffutures: (Default)
ffutures ([personal profile] ffutures) wrote2007-10-10 12:10 pm

Question for anyone with knowledge of home brewing

One of our biology experiments on the chemistry of fermentation uses a 10% yeast and 5% glucose solution which has to be set up a couple of hours in advance. Naturally this produces a LOT of froth - e.g. the 2L beaker I set up half an hour ago with 1L of this mix overflowed some time ago, and there's at least another couple of litres of froth in the tray. It ought to settle down by the time they're ready to use it, but a lot of the mix is wasted.

Is there anything like a reverse widget which will stop it from frothing over?

Two days later Had to do this again today, mixing the 1L of gunge in a 5L bucket just worked - the froth came up to the edge but it didn't go over.
drplokta: (Default)

[personal profile] drplokta 2007-10-10 11:45 am (UTC)(link)
A bucket.

[identity profile] ffutures.livejournal.com 2007-10-10 01:43 pm (UTC)(link)
Maybe - at least none of it would be wasted.

[identity profile] ffutures.livejournal.com 2007-10-12 03:05 pm (UTC)(link)
Had to do this again today, a 5L bucket worked - just! The froth reached the edge but didn't overflow.

[identity profile] parakkum.livejournal.com 2007-10-10 04:19 pm (UTC)(link)
Hmmm. So it looks like frothing in fermenting yeast is the result of a hydrophobic surface protein; the suspicion is that the hydrophobic proteins preferentially orient the cells along the carbon dioxide bubbles, effectively letting the yeast act as a sort of "living bilayer" (my words, not theirs).

Intuitively, I'd expect that adding a little more hydrophobic material to the mix would help, and it turns out that excess protein and lipid are both cited as problematic froth reducers in this patent. That suggests you could spike the mix with a bit of olive oil, for example, to calm the bubbles.

If no one's going to drink the mixture, I might potentially try some DMSO, actually. Although DMSO can act as an electron receptor in anaerobic respiration, I suspect that in moderate amounts it wouldn't be a huge problem.

Final caveat: I have only ever worked with yeast as an experimental organism. I have no personal (intentional) brewing experience.

[identity profile] ffutures.livejournal.com 2007-10-12 03:02 pm (UTC)(link)
I went with the bucket in the end - no worries about the chemistry.