Wyeast 2206 - Overattenuation Issues

[Zepth]

Thread title says it. I've used this strain 5 times now, and 4 of them have over attenuated. The first was about 90% from an all malt bill. This batch had an emergency overnight mash as life got in the way of brewing. Highly fermentable mash? Sure, let's call it an anomaly.

Similar results on the next two, but not as drastic. 80 and 82%. Just a bit higher than the website listing at 77% on the top end. Not too far off, I could live with this. I just ended up checking my latest creation after the D-rest / complete attenuation ramp and measured it at 1.008. OG for it was 1.058. 86% attenuation. Somewhat unusual and unexpected.

On this last one, it was a 90 minute mash at 65 C (149F). Nothing too outrageous.
Grist:
65% Pale Ale (weyermann)
12% each Crystal 60, Pale Wheat (head retention), Munich 10L

My note taking does need improvement. Some batches had a starter, some had direct slurry from the fermenter. In either case a yeast calculator was used to ensure there was no massive over or under pitching. Hydrometer readings only, always very near calibration and adjusted accordingly. There was an incident involving my previous hydrometer (RIP) and this newest batch is using the new one. I think we can rule out a bad calibration. Particularly since with every other yeast the readings are exactly as expected.

Fermentation schedule varied between batches. Either 8C or 10C (46 or 50F) for 2-3 weeks, then a ramp to 16 (60F) or ambient room temperature for said D-rest. Not that I'm sure it was really needed, I think the only thing accomplished was ridding the beer of a wonderful hop aroma. After a week there, a cold crash, fining and packaging.

Any experiences similar to mine? Any clue as to what it is that I'm doing out of the ordinary? I know the idea of "Oh well, more ABV" lives on, but loosing 8 points below your expected FG is becoming a bit of a bother. This wasn't supposed to be a 6.5%, it was supposed to be 5! Oddly enough, none of the beer with the over attenuation has been dry. It's always maintained a decent malt backbone.

 

[RM-MN]

Mashing long and low should give you a very fermentable wort so it should be no surprise that your yeast likes it so well that it overattenuates. Try a higher mash temp and shorten the mash to 60 minutes. If your brewhouse efficiency goes down from that shorter mash period, tighten up your mill a bit.

 

[dmtaylor]

Calibrate your hydrometer.

 

[daksin]

The attenuation numbers from the manufacturers aren't great. They're based on an underpitch (which they recommend) with no oxygen, among other things. If you're treating your yeast right, you can get consistently better attenuation then the manufacturer calls out. Rather than relying on that information, you need to work with the strains you like best so that you get an understanding how they will perform in your brewery, because everyone does things differently.

That being said, your mash is both cool and long, which will result in very very fermentable worts. Remember that no matter what mash temp you choose, a 90m mash at 149F will produce a more fermentable wort than a 60m mash. If you want less attenuation, definitely shorten your mash length, and consider increasing the temperature.

 

[stevehaun]

That is my favorite yeast and I get very consistent attenuation. For example, I mash my pilsener at 148F for 1 hour. OG = 1.050-1.052 FG = 1.009-1.010

I suspect your 90 min mash may be contributing to a very dry beer.

 

[Zepth]

Didn't mention it earlier but... One of the batches was a split batch with US-05 and 2206 and the latter chewed up the wort like nobodies business, and the US-05 behaved exactly as expected. This was a factor in thinking that perhaps 2206 is just hungry.

Thanks for the info. This latest "recipe" had rather useless guidelines as to everything except grist and hop schedule. I was on my own for mash temp, length, boil time, yeast and ferment temperature. Making it up as I went along certainly had an effect on this batch. I usually mash 68C / 154F or so for 60 minutes, but for some reason the idea "lagers = dry = low mash" popped into my head. And I mashed in before my brew partner of the day arrived, then I delayed the boil until he arrived as he happened to be late Hence the long mash. Without having made it prior and no instruction set to follow, it was a total shot in the dark either way.

Thanks for the info everyone. I was just all weird about things because I've only ever had attenuation problems with this one strain. Which also happens to be the only lager yeast I've used.

 

[WarblyTremolo]

If you like to mash low but need more body in the beer, consider some cara-pils or other dextrin malt to add unfermentable sugars to both raise the FG and create body. Melanoidin malt is also an option for lagers.

Of course, just mashing higher should do the trick as well.