Oktoberfest D rest

[anderj]

I have an Oktoberfest that I brewed Saturday the 9th, I pitched warm (70 F) and fermentation took off in about 5 hours. It took a good 18 hours for it to get down to 54 F. Starting gravity was 1052 and yesterday the sg reading was at 1021. So far it has been fermenting for 9 days but one was pretty warm. My mash was held at 154 for 60 min and I used Wyeast 2308 (Munich Lager)with a 1/2 gallon starter in each carboy (ten gal batch). When is it time to start a D rest by turning the fridge off for a while?
thanks
-ander

 

[Jaybird]

I am guessing when primary ferment is complete and you havent had a change in gravity for a day.
JJ

 

[Piotr]

used Wyeast 2308 (Munich Lager)

I heard that this strain is a major diacetyl producer, so I make really solid D-rest - after 2/3 of primary fermentation (5-7 days) I rise the temperature to 16-18C.
Results are good - clean lager, no floral flavours.

 

[BarleyWater]

It actually depends on your expected final gravity. You usually want to do a D-rest when about 75-80% to your final gravity. This lets the yeast do the work before they start to go to bed, but it's been long enough so that it won't create any fruity esters. If you wait until you have reached your FG, then the yeast will be asleep, and won't do any cleaning up thus leaving the diacetyl. Of course, some strains don't even need a D-rest, but I usually just play it safe and do one anyway, no harm.

Just set you fridge for the low 60s and let the beer rise up to those temps, let it set for a day or two, then gradually lower back down and begin to lager. I usually don't go more than about 5 degrees per day on the way back down to not shock the yeast so they can still work on conditioning and lagering.

 

[BarleyWater]

If you started at 1.052, and wanted to end at around 1.012ish, then now would be the ideal time to do a d-rest.

1.052
-1.012
0.040

75% of .04 is .03 so 1.052 - .03 = 1.022. About time for the rest.

 

[Shay]

According to wyeast, you want to wait till the end of primary fermentation: http://www.wyeastlab.com/hb_yeaststrain_detail.cfm?ID=133

 

[BarleyWater]

Benefits from temperature rise for diacetyl rest at the end of primary fermentation.

From WYeast, it says at the end of primary fermentation, not after. At the end would be the last 20-25%.

 

[menschmaschine]

Greg Noonan states (New Brewing Lager Beer) 6 points shy of expected FG. So, now sounds like a good time. I wouldn't necessarily turn the fridge off, per se. 60-65dF is a fine temp for a diacetyl rest. Also, you'll want to lager this for about 7 weeks to clean it up well.

 

[ChrisKennedy]

Raising the temperature of the fermentation is designed to maintain activity, not restart it. So, in other words, what they said. Now.