Attenuation vs Flocculation?

I was reading the NB all grain recipe kit for the honey kolch (really good, btw…we did the extract version about 8 months ago).

Under the yeast, it says this:

Wyeast 1010 American Wheat Yeast. A dry fermenting, true
top cropping yeast which produces a dry, slightly tart, crisp
beer, in American hefeweizen style. Apparent attenuation:
74–78%. Flocculation: low. Optimum temp: 58°–74° F.

I’m not really sure what this means? What temp do I ferment at?


when yeast are done fermenting - They drop to the bottom of the fermenter into a “yeast cake”. the act of falling out of suspension and compacting is “flocculation”.

and here’s a copy/paste about attenuation from white labs - “Apparent attenuation percentage is the percentage of sugars that yeast consume.” basically attenuation is a measure of the yeast’s ability to ferment sugars. measured by difference in original gravity and final gravity

here’s a good read from white labs if you’ve got some time

– I would ferment at 62-65 degrees Fahrenheit if you can. although I’ve never used 1010

For a clean Kolsch profile, fermenting at the lower end of the range will be best. I’d pitch at 60, and try not to let it get higher than 62 during the first week. This would benefit from some time at fridge temps after primary fermentation is over.

good advice. if you have a way to control fermentation temps - low 60’s would be best. If you search “swamp cooler” in terms of brewing. it’s a cheap and easy way to control fermentation temps

We’ve got a chest freezer with a Johnson temp controller on it.

Won’t be brewing this til January or Feb most likely.


That seems like an odd yeast choice for a Kolsch. Is that part of the kit, or do you buy it separately? If it were me, I’d save that for a Hef and get a Kolsch specific yeast. I don’t know if that will clear up, even with lagering. You could say that floc. and atten. tend to be inverse in a given yeast: that’s a high attenuation yeast, partly because it doesn’t drop out, it stays in the wort and keeps eating. A lot of English ale yeasts are just the opposite: they floc quickly, leaving more sugar in the wort, in other words, they are low attenuators, but they tend to clear up well. You might consider Nottingham for a Kolsch - it has good attenuation, is fairly flocculent, and it is good down into the fifties. Any way you go, good luck and merry Christmas.

I’m pretty sure that this was Widmer’s first yeast, a German ale yeast and their first beer was an alt. When they decided to brew an American hefe they used the yeast they already had.

I’m pretty sure that this was Widmer’s first yeast, a German ale yeast and their first beer was an alt. When they decided to brew an American hefe they used the yeast they already had.[/quote]
An Alt yeast should make a decent Kolsch yeast.

As I understand “floculation”, it is the tendancey of yeast to form into clumps. This is not necessarily dropping out of suspension or going dormant. Yeast that are “highly flocculent” do tend to clear well when they do finish though which probably helped lead to the common confusion over the term. Yeast that are “low floc” don’t form clumps so they tend to remain in suspension even after they go dormant. You can see this if you use glass carboys or better bottles. “Dropping out”, or going dormant at the end of fermentation is not flocculation…

That’s one of the yeasts that NB lists with the kit. You typically get a dry yeast by default, or u can opt for a Wyeast slap pack. This is the one they listed.

Dropping out or coming out of suspension is flocculation. Clumping is flocculation. The confusion, if there really is any, probably comes from the fact that the word means both things. The process in which yeast go dormant after fermentation, as you correctly stated, is not flocculation.
Flocculation is the yeast’s ability to clump and come out of suspension.
Attenuation is the yeast’s ability to convert sugar into alcohol.