I just pitched my first Saison, using WLP 565 24 hours ago. Bubbling nicely. I'm worried about diacetyl, am I paranoid? Aroma section of the beer judging style guide says "no diacetyl" in the aroma section for Saisons.
Has anyone had a Diacetyl problem with any of the yeasts from white labs below?
As long as your yeast is healthy and abundant and you're not cold-crashing the beer as soon as fermentation tails off, you'll be fine. I've fermented with a number of Saison and Belgian strains (though I can't remember which off the top of my head) and I've never had any problems with diacetyl. Also, basically any strain that's known to produce diacetyl in over-abundance will say so on its spec sheet.
The elevated temperature many Belgians ferment at is actually a boon to yeast's reduction of diacetyl to flavor-neutral compounds after primary. Also, most Belgians are medium to medium-low flocculators (highly flocculent yeast tends to leave more diacetyl around). More yeast in suspension = more power to reduce diacetyl post-fermentation. To be safe, there's really no reason not to just let your beers sit for a week at primary temperature after fermentation is done to make extra sure all the D is gone. A small, virtually risk-free step you can take to ensure good beer.
As far as I'm concerned the 'No diacetyl' comment should be applied universally (if you read a lot of BJCP guidelines, you'll see it so many times you'll stop even noticing it). Luckily, provided you follow the general practices of good fermentation, it's really one of the easiest off-flavors to avoid with pretty much any ale yeast.
My co author, Drew Beechum, is pretty much recognized as the master of saison. In our book "Experimental Homebrewing" he writes about 565 and how temprementl it can be. For one thing, you need to raise the temp into the 80s after the first couple weeks in order to get the yeast to finish. That will clean up a lot of the diacxetyl. Most surprisingly, it's incredibly sensitive to the smallest amount of back pressure, which will cause it to stall. To combat that, he ferments open at first, then just covers the fermenter loosely with AL foil. Anything that causes the yeast to stop working will prevent it from cleaning up diacetyl. All of this info is on pg. 123-127 of "Experimental Homebrewing".
