Diacetyl Rest

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Permalink Reply by Dougal on July 24, 2012 at 10:39am

Diacetyl rest needs to happen at the end of active fermentation so that the yeast can actively scavenge their byproducts. A good time to do it is when krausen starts dropping back in. Aim for about 3-5 degrees above the fermentation temperature, and as for time, well it depends. Some people say a couple of  days, I go a bit longer (5 days), with lagers as I also want to get rid of any sulfur produced at the cooler fermentation temperature.

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Permalink Reply by Jarob of Ale-tearoa on July 24, 2012 at 11:41am

Cheers Dougal, I've been doing the rest after primary has finished and for about 3 days, give or take a few hours, unfortunately I forgot to turn off my heat pad the other night and by the morning it was up to 20^c :( ...so yeah we'll have to wait and see the outcome of that...

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Permalink Reply by Reece on July 24, 2012 at 1:13pm

I dont see any issues with 20c. That is perfectly fine for Diacetyl rest. Someone with more experience may be able to help more though.

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Permalink Reply by Tilt on July 24, 2012 at 1:23pm

20C should be fine - as long as your heat pad wasn't in direct contact with the bottom of your fermentor - if so its likely the yeast cake got a bit hotter than 20 and you might have some yeast autolysis flavours.

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Permalink Reply by Jarob of Ale-tearoa on July 24, 2012 at 3:08pm

Poo's... Only the black tee shirt the fermenter is wrapped in to protect it from the heat pad...

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Permalink Reply by Rhyno on July 24, 2012 at 3:54pm

Interesting, I hadn't thought of that either. I have a light bulb sitting underneath my fermenter. Might have to move it for the next brew

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Permalink Reply by Tilt on July 24, 2012 at 5:16pm

You never know til you try it but I got a layer of dark brown yeast and an odd burnt tyre flavour in a Blonde from what I figured was a direct contact with heat pad a while back. 

Nowadays I stick a piece of 19mm pine on top of the pad as an insulator/ heat disperser.

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