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-   -   Diacetyl Rest (http://www.homebrewtalk.com/f13/diacetyl-rest-12449/)

Glibbidy 08-18-2006 05:13 PM

Diacetyl Rest
I have a pilsner in the primary fermenter that I pulled out of the Fridge this morning to perform the Diacetyl Rest. I'm raising the temp to ~68. Now for the million dollar question:

How long do you lager beer makers typically shoot for when doing a Diacetyl Rest?
I have been researching this, and getting mixed answers. Response are all over the place fro 24-28 hours, to "When fermentation is complete".

It was in the primary for seven days at 52f. I initially pitched a 1 gallon starter at 70f, and then cooled to 52 after I noticed the krausen take off (after aprox 6-8 hours.) I would like to avoid sticking anything in the primary if possible, i.e. a hydrometer, or graduated cylinder to perform the "Force test"

Monster Mash 08-18-2006 05:33 PM

I usually let it sit for about 48hours at 68 degrees. I don't rush my lagers and it definately doesn't hurt to let it sit longer to allow for it to clean up diacetyl.

The main reason I let it sit longer is because I brew large batches and it takes time for the beer to warm up.

Glibbidy 08-18-2006 05:36 PM

This is a 10 gallon batch I have in the primary. Do you just eyeball it as far as temps go when you pull it out of the cooler?

mysterio 08-18-2006 07:02 PM

I usually play it by ear. When the bubbling slows down to say 2 or 3 bubbles a minute, usually after 14 days or so. The rest usually takes 2 or 3 days. I actually do it to squeeze a last few gravity points from the yeast.

Baron von BeeGee 08-19-2006 09:59 PM

I've only done it once, so take this for what it's worth. My research led me to understand that the yeast need to be actively feeding to perform an effective d-rest. Therefore, I pulled mine out of the fridge when the SG hit 1020 and I left it until it finished a couple days later (~1011 IIRC). Then I began lagernating it.

Gabe 08-19-2006 11:42 PM

Brew did an article on this a few months ago.(Take me to your lager) Aside from pitching yeast at ale temps untill fermentation really takes off, then a 10-15 day ferment at 50-55 deg, then a 72 hr warm up to 68-70 deg for Dycatel rest. Then siphon to secodary leting some yeast into the secondary as Lagering needs the yeast. Put this back in the fridge and decrease temp no more than 2 deg every 24 hrs until your hovering above 32. I have followed this on multiple Lagers and pilseners. Awsome beer turnout and once you get the flow it's rather easy. A fridge temp controller is essential to the process. Good luck. cheers

boo boo 08-20-2006 02:14 PM

Ok if you are not going to verify your gravity readings (and this is alright) then you need to determine by some other method as to how far along in the ferment you are. Usually when you are 2/3 of the way to terminal gravity you raise the tempertures to about 60f for a diacetyl rest. So if your bubble rate has slowed to what it was when was activly fermenting and your krausen has dropped, then you can do the rest. Most of my lagers ferment to two weeks before I raise the temperture for the rest. I like to complete my fermentation before racking to lager the brew.
I then drop the temperture to about 34f over the next few days and lager for at least 2 months.
BTW, for an even better tasting lager try to pitch your starter that is at fermenting tempertures into wort that is at fermenting tempertures. This will eliminate a lot of potential ester and fusel alcohol formation.

Good luck

Glibbidy 08-21-2006 01:18 PM

I ended up keeping it in the primary for 8 days at 52, and racked to the secondary last night after a 60 hour Diacetyl Rest. The fridge is set about 50f, so I figure the temp in the secondaries will drop slow enough to not shock the yeast. I'll start dropping the temps tonight and shoot for 32f since the fridge's stoick temp controller simply has that dial with 1-5 on it.

*crosses fingers and knocks on wood*


Originally Posted by gabe
A fridge temp controller is essential to the process.

That's what I was afraid of. Any suggestions for a simple A fridge temp control device?
From What I have researched so far, it seems that it might be cheaper to buy one, than hack something together, but I am open for suggestions :confused:
I'm not an engineer by trade, so as a result fairly inept when it comes to this stuff:(

boo boo 08-21-2006 11:24 PM

It is nice if you could keep your secondary tempertures as even as you can get them. Around the 32 to 34 mark seems nice, I use thermometers inside my lager fridge to moniter the internal temps in the fridge.

I did lagers before getting a temperture controller and could never keep the fridge at a steady range.

Glibbidy 08-22-2006 02:14 AM


Originally Posted by boo boo
I did lagers before getting a temperture controller and could never keep the fridge at a steady range.

The writing is on the wall here for me to get something going as far as a temp controller. Sounds like a critical tool for lagering it the right way.

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