Roxy Rolles D-Rest

[funkenet]

They said to D-Rest this beer at the end of fermentation. Ive never done a D-rest on an ale. How do you do this and why?

[brewinhard]

I haven't had a chance to listen to that one yet, but I am assuming they are talking about a diacetyl rest. This is usually done if the yeast strain one is brewing with (English, Irish,etc) tends to put out diacetyl when fermenting. A diacetyl rest is simply either letting the beer warm a few degrees above fermentation temp for 2-3 days to allow time for the yeast to clean up any off flavors (buttery diacetyl) before cold crashing/bottling/kegging or racking the beer off the primary yeast cake. If you usually let the beer sit for 2 wks in primary anyway you will probably be okay providing the beer does not get too cold.
They may have required a D-rest simply because of the yeast strain being used in this case though.

[funkenet]

Another question about D-rests. When I did a D-Rest for my Helles Lager it was easy because I could just take the beer out of the 40F fridge. With my ale it is just sitting at the ambient 68F right now. I was thinking I could put the fermenter in a bath tub and keep adding hot water to it. Would this work and what temp should I be shooting for?

Thanks

[brewinhard]

Which yeast did you use? If it was me, I honestly wouldn't worry too much about raising the temp. Just give the beer its due time on the primary yeast cake (2 wks) before racking. Keep it at the fermentation temps or so, and the yeast will clean up any residual diacetyl produced during fermentation. I have never noticed any diacetyl in my beers. Maybe i just have a shitty palate or a high threshold for tasting it. Usually time and average temps (high 60's) should take care of any of that.

Magic Hat may have performed a d-rest simply because they have to keep the beer rolling out of their brewery, meaning that their turnaround is faster than a typical homebrewer and they may have fermented at a higher temp than most of us would to speed the beer along. What temperature did you ferment at?