Yeast and Attenuation

Yeast & Fermentation
1

When a yeast manufacturer states a yeast as x to x attenuation (for example WLP is 73%-80%), do they mean real or apparent attenuation?

Thanks!

2

Good question! I think the answer is apparent attenuation. That’s how I use it. But I could be wrong.

3

AFAIK, it’s apparent. At least, that’s what I gave Wyeast for 1450 and that’s what they use. And FWIW, the attenuation rating is just intended for comparing one yeast to another using a standardized wort. It’s not necessarily an indication of the attenuation you’ll get. That’s pretty much dependent on the composition of your wort.

4

Thanks guys. Denny, that is what I figured. Currently, I am looking at how the same yeast preforms for me batch to batch. When I was looking at some of the descriptors on the WL site it got me thinking about it.

Again thanks!!

5

I’ve found the apparent attenuation values provided by the yeast manufacturers to be reasonably accurate and consistent within a couple of points from batch to batch when using 10% or less crystal malt and mash temperatures of 148-152 F. YMMV