I occasionally get some diacetyl, especially in darker ales. I’m sure it’s not contamination or equipment sanitation issues. I originally thought that it may be caused by fermenting in the 62-64 degree range, but don’t really think that’s the problem, because a longer fermentation time should take care of that, and I’ve had some slight diacetyl even after primary fermenting for 2 weeks and secondary for another 10-11 days. I recently got water quality results and saw that my calcium levels are only in the 8-14ppm range, and I’ve read that it should be a minimum of 50. Could low calcium cause diacetyl issues, and would adding some gypsum take care of this. Thanks.
I don’t know of any correlation between diacetyl and calcium levels. I do understand that higher calcium is supposed t make the yeast drop out more quickly. First, are you sure it’s diacetyl? Not that I don’t trust you, but it needs to be asked. Second, have you looked into other causes of diacetyl? Possibly you have a low level contamination that’s doing it.
Thanks for the comment. Pretty sure it’s diacetyl- butterscotch smell with slight sweetness in the taste. I don’t think it’s contamination because it doesn’t happen all the time or with the same equipment. If low calcium is likely not the problem, could it be from fermenting at around 62 degrees?
If it was fermenting at 62 degrees, then every batch I ferment would have diacetyl. So no, I can’t imagine it’s from that. Does it happen with every yeast strain you use or just some?
Yeah, same here for most ales. I’d be curious to hear what strains OP typically uses.
It’s just some yeast strains. More often the Scottish and Irish Ale strains. It only happens about once every 8-10 batches. I keep everything pretty clean, but I think I’ll just go ahead and thoroughly clean everything now - kegs, lines, fermenters etc. just to rule out any contamination.
I’ve never had that issue with the Scottish strain even at 58-59F, but the Irish strain is known to sometimes have low level diacetyl IIRC. No big surprise there.
I almost always get diacetyl from Irish ale yeast. Which is why I don’t use it any more.