Terminology.

[Jimberbob]

What does attenuation and floculation mean?
Is there a good book about yeast so I can gen up on something I know so little about?
Ta!

[steve_flack]

Attenuation is a measure of how much of the sugar gets used up by the yeast. A highly attenuating yeast makes a drier beer.

Flocculation is when yeast cells clump together and sink to the bottom at the end of the fermentation. A good flocculator is one that drops out quickly - like S-04.

[anomalous_result]

Does a high flocculating yeast need more time in secondary?

[niall]

A high flocculating yeast will clear your beer faster so in that respect it needs less time in secondary. However the beer will still need time to mature.

[anomalous_result]

Sorry, perhaps I've got my term for secondary wrong there. Say you bottle it rather than cornie. If the yeast falls out of suspension quicker does that mean that when you bottle it there will be less yeast so it will take longer to carbonate? Or is the effect of high floculation only noticeable in the days after fermentation's stopped rather thna hours.

[niall]

There will still be plenty of yeast present for carbonation if you're bottling. S04 is a popular choice for bottling as it flocculates really well - it sticks to the bottom of the bottle which means you have less sediment floating in the beer.