Why does yeast flocculate? :confused:

[cjyh84]

Hiya,

I was wondering, what's the physics/chemistry behind yeast cells (ale yeast at least) falling out of suspention i.e. flocculating? And by the same token, why does yeast stay in suspention?

I googled the question but the answers were highly technical/sciency for me to understand. Anyone here care to offer an explanation in simple english?

From what I gather, ale yeast simply falls out of suspention because, somehow, it binds with other yeast cells and their weight becomes enough, thanks to gravity I assume, to drop to the bottom of the vessel.

Also, how does flocculation influence brewing? In other words, how does yeast flocculation translate for brewing purposes? e.g. when racking to a secondary; filtering; cleaning-up (diacetyl reabsorption); reaching FG; etc.

Thanks!

 

[unionrdr]

When the yeast has eaten all the simple sugars,it then goes after the copounds that are by products of fermentation that can produce off flavors. This usually happens after FG is reached. Mine typically take 3-7 days to do this & flocculate,or settle out. They're not dead,just going dormant since all their "food" has been consumed.
As stated,this is good,since all the fermentation by products they've eaten go to the bottom with them. It leaves clear,clean beer,which is the first step in conditioning really. Then priming/bottling,& bottle carbing & conditioning takes this another step further toward better tasting,carbonated beer. At least a week fridge time finishes this process by getting co2 into solution,& settling everything including chill haze to the bottom of the bottle where it becomes compacted with the right amount of time.