Consistently high attenuation with WY1968

[303Dan]

Anyone else getting significantly higher attenuation with WY1968 than the specified 67-71% per Wyeast on a regular basis?

I seem to consistently get 75-80% with this strain on all different beers. Most recently, it took a 1.070 OG IPA all the way down to 1.010 for a whopping 85% AA. That beer, in full disclosure, was designed for high attenuation (Long mash at 147, 1/2lb of Dextrose at the end of the boil, etc), so I'm not surprised it attenuated well, but I still wasn't expecting 85%.

I do pitch at a fairly high rate, around 1.25 million cells/ml/P°, and oxygenate with pure O2 for 45-60 seconds. Usually with 1968 I'm fermenting at 66°F until I'm about 4-6 points from FG and then I ramp up 1-2°/day until 70° and then hold it there.

Anyone else getting similar results outside the specified range with this strain?

 

[HTH1975]

Best to know how fermentable your wort is, rather than rely on average attenuation of yeast.

 

[ccous]

You already answered your question. Long mashes at low temps.

 

[thehaze]

I recently used Imperial A09 Pub, which is the same strain and I got 74 and 75% AA in two different beers, with a short 60 minutes mash at 149 and 151F. No sugar, or anything.

Iimagine if I was to use sugar and mash at 147 for 90-100 minutes, it would probably go close to 80%, or even more.

 

[303Dan]

Yep, I definitely expected attenuation to be higher due to the long mash at 147, just wasn't expecting quite that big of a jump. I had already changed the yeast details in Beersmith for 1968 to 74-78% AA to reflect the results I was getting even with more standard 60 minute mashes at 152. I'm going to have to figure out how Beersmith does the math to adjust attenuation for various mash temps so I can dial it in a little better.

I liked the result in this case as I was trying to get this beer as crisp and dry as possible.

Anyway, I love the strain, and I'm starting to get it dialed in as my house yeast. I feel like I have a better understanding of what it will do under certain circumstances after this beer.

Just curious to hear if others are having similar experience with this strain.