Diacetyl rest for dry stout?

[shawnbou]

On Saturday I made a dry stout from Jamil Zainasheff's "Cerveza de Malto Seca" recipe in Brewing Classic Styles. I'm fermenting in my chest freezer with an ambient temperature range of 62-65°F per JZ's instruction to ferment at 65°F.

My question is, JZ recommends a diacetyl rest at 71°F for the final third of fermentation. I've never brewed a lager so I have never done a diacetyl rest before, and this is the first time I've seen an ale recipe call for one. Is it even necessary at these temperatures?

My thought is to just unplug the freezer when fermentation starts to slow down and let the temperature gradually get back up to room temperature. I usually only keep the freezer going for the 7-10 days of fermentation anyway, so I'd just be doing my usual process ... just a few days early.

If a diacetyl rest is really recommended for this style, is this all I need to do? Or am I missing something?

Thanks.

 

[GMesick]

Even though 1084 is an ale yeast, it throws off alot of diacetyl. So if you do a diacetyl rest, it will result in a cleaner beer. A 10 degree temp raise is about right.

So either take a SG reading and start the rest then, or wait until the bubbles slow and start it.

I'm not sure that just turning off the fridge will get you there. It's an insulated box, after all. It's meant to hold temp. I would move it to a warmer room. My own practice involves attaching a temp probe to the side of the fermentor and applying heat (with a fermwrap) or cold (because it's in a son-of-fermentation-chiller) to get the fermentor (not the air around it) to the proper temp. I brew lagers almost exclusively, so I have quite a bit of practice--and I am a great believer in better beer through temperature control.

 

[shawnbou]

Thanks GMesick.

I actually have a little office-cubicle-sized space heater. I'm thinking I could hook that up to my thermo controller and place it in the freezer, on low and pointed away from the fermenter so there's no hot air hitting it directly.

Assuming I monitor it and keep it safe, that could work, right?

 

[mdgagne]

Sure - I use a brew belt in my ferm. chamber to raise temps. They're pretty inexpensive. In general, I raise the temperature of my ales over time to reinforce proper attenuation. After the first 36 hours of active fermentation increasing temperature is generally a good thing. It keeps the yeast in suspension and causes them to metabolize compounds such as diacetyl.

 

[GMesick]

Thanks GMesick.

I actually have a little office-cubicle-sized space heater. I'm thinking I could hook that up to my thermo controller and place it in the freezer, on low and pointed away from the fermenter so there's no hot air hitting it directly.

Assuming I monitor it and keep it safe, that could work, right?

Yes--that's the idea. With your caveats, it should work. And the fermwraps are cheap, safe, and effective, should you decide this is something you need to do over and over.

 

[shawnbou]

I put the heater in the chamber last night and I've been gradually ramping the temperature up 1 degree every couple of hours. Up to 71°F now. Thanks for the suggestions, everyone.