High attenuation with s-33

[bransona]

I recently brewed a SMaSH and an EPA with the infamous s-33. Both attenuated well over 80%, one being 89%. I'm not displeased, as it made great beer. I even harvested the yeast to see if it'll chew through the next batch just as well. Mostly I'm just surprised. This yeast doesn't seem to ever give attenuation like that. Both were mashed low (148* range). Hydrometer readings were accurate. Fermented at ambient 64.

The SMaSH ended up going from 1.045 to 1.005. The other was somewhere slightly upwards of 1.060 and wound up at 1.006.

Again, great beers were made so there's no upset there. But why is the attenuation so high?

 

[casualbrewer]

Probably because you mashed low and fermented it warm.

 

[bransona]

The batch I fermented warm (68*) to get Belgian esters aactually had poor attenuation from this yeast.

 

[Big Monk]

Probably because you mashed low and fermented it warm.

64 degrees is fermenting warm?

 

[casualbrewer]

Pretty sure s-33 is a lager yeast correct? Probably much happier in the mid 50's.. and ambient 64 degrees may mean mid 70's depending.

 

[JKaranka]

S33 is a British ale yeast that used to be the EDME strain by what I've read. I guess that if you push it you will get some Belgian-lite character but by most reviews it's cleaner than most Belgian strains.

 

[bransona]

It is edme. Definitely a British ale yeast that yeah, you can squeeze some lite Belgian flavor out of at those temperatures. Reminds me of Roquefort. It's definitely not lager though. 64 is a super clean temp for it

 

[Leapsandbounds]

First necro for me...

I read a lot about this yeast under attenuating so I planned for about a 70% AA (also the average AA listed by brewer’s friend).

I mashed at 152 and had an OG of 1.060. I fermented for just under 3 weeks around 68-70 degrees f and to my surprise the FG was 1.008! (I was expecting a FG of 1.018)

Also, this stuff does not flocculate well. I hit it with gelatin so hopefully it will clear up a tad.

I wanted to add my experience to the interweb because it would seem that I’m not the only one that has experienced high attenuation with S-33.

 

[STMF]

Contamination could cause high attenuation and hazy beer.
Just sayin...

 

[Leapsandbounds]

Contamination could cause high attenuation and hazy beer.
Just sayin...

I believe it’s known to have low flocculation.