diacetyl rest for S04

I just took a sample from my batch that’s been in the fermenter for 12 days and is currently at 64F. I ran between 64-66 for the majority of fermentation although it did creep up to 67-68 for half a day a few days in. I am getting a bit of diacetyl and would like to get rid of as much as I can. What temperature should I raise it to and for how long? I was planning to keg later in the week.

It’s pretty much a mongrel of a beer although it is light colored, light bodied, and low abv. I probably should have chosen a different yeast but thought what the hell…

is it still working? if there isn’t any gravity points left for the yeast it is unlikely that you will be able to get rid of the diacetyl. This is one of the problems with british yeast in general (sweeping generalization alert) and why you have to be careful and hold their hands while they finish their job.

you can try bumping the temp up to ~70. it’s not going to hurt the beer at this point. If it doesn’t help you might be able to krausen the beer to clean it up but it will require a large pitch of very active yeast. Basically you pitch a huge starter or some very fresh yeast from a brewery into your batch (like a 4 liter starter or a few hundred ml of fresh yeast) while the yeast is at high krausen. the yeast, not finding any sugar source will chow down on those pesky metabolites as second choice.

I assume it is done fermenting. I got 83% attenuation for a FG of 1.007 which is what I was expecting. I didn’t realize that you should do a rest while it is still fermenting so that is good to know. I thought you were supposed to wait for it to finish but I guess that doesn’t make much sense.

I roused the yeast and will bump it up to 70 for a couple of days and just not expect any changes. Thanks!

Would bottle Conditioning instead of kegging fix it some i wonder?

You may get lucky just leaving the beer on the yeast cake for a bit longer and raising the temps as you did.  Rousing the yeast can sometimes help to reduce that character a bit too.  When I used to use that strain frequently, I would always get a pronounced doughy aroma and flavor from the yeast at first.  That eventually would fade away.  Maybe the diacetyl note is compounded by this flavor as well?

Good point. I haven’t quite figured out how to use this yeast for what I want so I may need to find a different dry substitute. I have used it multiple times but feel that I get different results. I guess I need to focus on my fermentation temps more closely. I tried to do that this time so we’ll see how it turns out.

This is what I would do. Its worked for me in the past!

S04 (and several other heavy floc strains) have a tendency to drop out and leave some diacetyl behind. As long as they aren’t stressed, they’ll reabsorb the diacetyl if forced back into solution.

Bring up the temp slow and easy (1 degree F/day or so). Keep the temp steady, and bring it down slowly when you cool (preferably after kegging/bottling).

I’ve had enough bottle-conditioned, diacetyl-ridden homebrews to say ‘probably not’, but I’d be interested to know if yeast releases/takes up diacetyl during bottle conditioning.

I wouldn’t be too motivated to bottle a beer with high diacetyl. If I can’t fix it beforehand, I’m not wasting the bottles/keg/fridge space.

If rousing doesn’t work, you could make a small starter and pitch it at high krausen, or krausen w/ another fermenting beer.

I have become sensitive to diacetyl and this batch has what I would call a very low amount as far as I can tell. Part of the problem is it has a very transparent malt flavor since it is essentially a very low ABV wheat beer grain bill so the diacetyl is much easier to pick up. There is nothing to make me believe that this batch is worth dumping…at least at this point.

I took the fermenter out of the water bath and it rose to 70 in less than a day so I put it back in the water bath where it is now. I did not mean to raise it so fast but we have hit a bit of a heat wave here and my house is pretty warm…

I will just have to go with it and see what the outcome is.

hmmm. I did not realize it was a wheat beer. are you 100% sure it’s diacetyl and not just wheat being slick like wheat will? you say a very low level. Is it low like 'I can’t taste it but I feel in in my mouth" or is there actually a buttery/butterscotch flavor? you can warm a sample in a covered glass in warm water for a few minutes and then smell to know for sure. the diacetyl will become very apparent if it’s there even at a low level.

Its a mongrel of a beer which I didn’t post because I assumed most would wonder what the hell I was thinking…

It is basically 40% wheat 10% rye and Vienna for the rest. All hops added after 20 min for about 20 ibus and fermented with s04. 05 would be more appropriate but I wanted to experiment

I get a light butterscotch type flavor outside of the hop flavor. I will do that test when I keg in a couple of days.

That describes almost every beer I brew :slight_smile:

So I just kegged this. I did as you suggested with a covered sample in warm water and could not detect diacetyl. The aroma is actually pretty fruity from the hops but not in the flavor so much. I think I may have somehow been mistaking diacetyl for the resulting flavor contributions from Vienna and the yeast as I am getting sort of a nutty character as well?

Either way I think I am good. Maybe just a weird combination of flavors. Now I just need to decide whether to pitch the pale ale that I am brewing now onto the yeast cake or just use my old reliable US05…