Diacetyl in Smurto's Belgian experiment

[82Mike]

I recently brewed an AG Smurto's Golden Ale- I've done several before fermented with US-05 but for this one pitched a litre starter of Wyeast 1762 Belgian Abbey II.

Primary Fermentation went as expected at 20c. for 4 days- it went from 1048 down to 1012 in this period. Tasting the wort I noticed a very strong butterscotch aroma and taste- what I understand is diacetyl.

I've left it in primary and let it free rise for a week- it got up to 25c. It has cleaned itself up quite a bit but the butterscotch is still present, especially in the taste (not so much aroma).

Does anyone have any suggestions? Is it likely to keep cleaning up with further time on the yeast cake? Should I pitch more yeast- say US-05- to consume the diacetyl? Would bottle conditioning be likely to help?

Thanks for the advice; I've been brewing for a few years now and never had any issues with diacetyl.

 

[manticle]

Has the diacetyl reduced in that time? Any other unpleasant flavours or just the butter/toffee notes?

If it's reducing, I'd leave as is for a shade longer. If the same with no other bad flavours you can add more yeast but make sure it's a healthy, active starter.
If other flavours, it may be bacterial infection, in which case there is little hope. A brett addition would be the only possible fix if you want to go down that road.

 

[mje1980]

Have you used that strain before? The Belgians throw lots of esters, is it definately diacetyl??

 

[manticle]

Yeah I got lots of red apple dominating when I use it - comes into balance after fermentation and conitioning though. Got a tripel at the moment using it that has lovely candied pear now.

 

[dammag]

What is the mouthfeel like?

Is it "slick" or "oily". Diacetyl can affect the mouthfeel of the beer. I get this more than the aroma or taste in some beers I have tasted with diacetyl.

 

[82Mike]

There are no other off flavours or aromas- in fact, it is tasting like a great beer in the making aside from the overt butterscotch. This makes me think it might be a fermentation by-product and not an infection (fingers crossed).

It isn't really oily in the mouthfeel.

It has reduced a bit over the week since primary finished. It started out tasting like butterscotch sauce and having a very strong butterscotch aroma. The aroma now is practically gone and but you can still taste it (though the malt and hops are also coming through more now).

I hadn't used this strain before- I made a big starter and split it. Half into my Smurto Golden and I am going to step up the other half for a Belgian Blonde (Jamil's Lefty Blonde from Brewing Classic Styles).

Perhaps it will come good with another week or two of conditioning. Should I keep it at room temp or cold crash it and condition it at 2-3C?

 

[manticle]

Room temp for a few days and reduce temp slowly rather than crashing. Taste in a few days before starting temp drop.

 

[82Mike]

The beer cleared right up given a week or so at 25c- it has turned out a really tasty brew. Kegged and ready for NYE. Thanks.

 

[panzerd18]

Time at fermentation temp is the great healer.