Diacetyl rest?

zacster · 02-28-2009, 11:53 PM

My lager had been fermenting for 10 days at about 48-50 degrees, sometime even lower, depends on the weather. But yesterday, the temp in NYC peaked at 61. The beer itself was up to 56 in the fermenter. Since it had already cooled down outside I let the beer cool down with it. It is much colder today, so the temp is back down to 52 and probably still falling.

My question is this: Did I get a diacetyl rest by letting the temp go up to 56 in the carboy for about 24 hours? Or does it take longer than that, or needs to be warmer? The fermentation is still going, my gravity reading yesterday was 1.020, it should go down closer to 1.010.

I was hoping to transfer to the secondary this weekend, but I think I'll let it sit another week in the primary. The weather is supposed to stay cold all week so I'll have good refrigeration. I have a mid-April party that this is supposed to be for and my count says it won't quite make it, 4 weeks to lager, 3 weeks in the bottle. Maybe I need to buy a keg setup so I can force carb it.

**BlindLemonLars** · 03-01-2009, 03:42 AM

The rest is usually a little warmer, and a little longer, and not done until primary fermentation is essentially done. But if you pitched cold, there may not be any need for a rest. Unless you taste diacetyl at this stage, I wouldn't bother.

**Revvy** · 03-01-2009, 03:48 AM

The rest is usually in the high 60's - 70's (whatever your "room temp" ) is for a minimum of 72 hours...Mine have been between 72 hours and a full week, depending on my schedule...

If you haven't read it, I can't recommend Bm's thread highly enough...http://www.homebrewtalk.com/f13/preventing-diacetyl-hold-butter-please-70438/?highlight=butter

Professor Frink · 03-01-2009, 03:54 AM

Like Blind and Revvy said, you probably didn't get a full rest, but not all lager yeasts require diacetyl rests. The best way is just to check the beer when you're about 3/4 through fermentation, you can usually tasted the diacetyl.

Kaiser · 03-01-2009, 04:16 AM

You should see the diacetyl rest less as a rest soley for reducing diacetyl and more as a warm rest for accelerated maturation and fermentation completion. When I do this rest it is for getting the gravity to the FG such that I can then crash the beer to 34 F and lager for 4-6 weeks. Lager fermentations can be sluggish and the yeas may need that extra help to finish the beer. Otherwise you may end up with a sweeter than desired product.

Kai

**bmckee56** · 03-01-2009, 12:47 PM

Quote:

Originally Posted by BlindLemonLars

The rest is usually a little warmer, and a little longer, and not done until primary fermentation is essentially done. But if you pitched cold, there may not be any need for a rest. Unless you taste diacetyl at this stage, I wouldn't bother.

(sort of) What would "Diacetyl" taste like? I have an Imperial Stout that may have excessive diacetyl and I currently detect something in the flavor (like cleaning solution or chemical flavor), but I am to new and unfamiliar to determine if it is this or something else.

Salute!

**Yooper** · 03-01-2009, 12:58 PM

Quote:

Originally Posted by bmckee56

(sort of) What would "Diacetyl" taste like? I have an Imperial Stout that may have excessive diacetyl and I currently detect something in the flavor (like cleaning solution or chemical flavor), but I am to new and unfamiliar to determine if it is this or something else.

Salute!

In large amounts, diacetyl tastes like butter, or butterscotch. In small amounts, it may just give you a "slick" or oily mouthfeel or a slick feeling on your tongue.

It's not out of place in some beer styles, but definitely out of place in a lager!

**Revvy** · 03-01-2009, 01:27 PM

I mentioned in another thread a couple days ago that I bought a sixer of Rogue Dead Guy, for the first time in awhile...I have had it on occasion in bombers, but decided on a sixer.

5 out of the 6 that I have had so far all taste like butterscotch, heavily of butterscotch...Which is really odd...I haven't noticed it in the bombers I've picked up on occasion...

Strange.

**FireBrewer** · 03-01-2009, 02:27 PM

Quote:

Originally Posted by zacster

My question is this: Did I get a diacetyl rest by letting the temp go up to 56 in the carboy for about 24 hours? Or does it take longer than that, or needs to be warmer? The fermentation is still going, my gravity reading yesterday was 1.020, it should go down closer to 1.010.

The diacetyl rest is a means for the yeast to clean up after themselves when they're done. So, since in your case the gravity was 1.020, they're not done and it wasn't a diacetyl rest.

Quote:

Originally Posted by REvvy

5 out of the 6 that I have had so far all taste like butterscotch, heavily of butterscotch...Which is really odd...I haven't noticed it in the bombers I've picked up on occasion...

Maybe your palate has just improved? Or maybe it was a bad batch.

I remember reading that the minimum flavor threshold for diacetyl was one of the lowest and that in terms of flaws, it's one of the most easily recognizable. Some flaws I have a hard time picking out but diacetyl sticks out like a sore thumb with me.

Blech!

**Revvy** · 03-01-2009, 03:31 PM

Quote:

Originally Posted by FireBrewer

Maybe your palate has just improved? Or maybe it was a bad batch.

I swear I picked up a bomber of Deadguy a couple weeks ago and didn't notice...I might have to do that...or maybe you are right, and my palate has become more sensitive....the other possibility is that I've become so used to my clones of Dead guy that I've forgotten what the original tastes like....But I still think I got a bad batch....

I know that it can be a result of fermentation, or certain infections...but I wonder of storage issues (like temp shifts or too high a storage) could cause it as well...