Skimming Out Barms: Is That A Legitimate Way To Lower Attenuation?

[dmtaylor]

It has some hint of a flavour completely new to me, I'd call it "rustic", "wood-like" or "hay-like", it's not unpleasant and I think it's the flavour of unconverted starches (the beer is still murky and opaque).

Starch is flavorless. Sounds more like husk compounds and perhaps tannins and/or tannic acid.

Interesting that the hot mash still gives normal attenuation. More fuel for hypotheses that mash temperature might just not matter as much as people think! At least with respect to low attenuators like M10 / S-33 / London, and their close relatives Windsor / M15 / Munton's.

 

[Protos]

I doubt the woody flavour might come from the husks: I know husk flavour well as I have very hard and alkaline tap water and prior to starting modifying it I experienced a lot of problems exactly because of its interaction with husks.
The water I used this time had been decarbonated by slaked lime, but not acidified so it had quite a high pH. That's probably what made my Hvidtøl a bit more tart than I expected. However, I find zero familiar husk flavour in it. The woody note is completely new to me, I've never experienced one before as I've never had fermented an underconverted wort. So I suspect it to be an impact of starch, as the beer has a plenty of it still in suspension.

It may be also me being a bit too quick to assume it was exactly the Workhorse that was responsible for the 63% attenuation. I better wait for 1 to 2 weeks more and see where the fermentation proceeds. If attenuation keeps going down, the overattenuation (not really yet, but who knows where it is in a week) and the woody flavour may well be from some bug, happily munching on unconverted starches.