Diacetyl rest?

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.

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.

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...https://www.homebrewtalk.com/f13/preventing-diacetyl-hold-butter-please-70438/?highlight=butter

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.

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

BlindLemonLars said:

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.

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(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!

bmckee56 said:

(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!

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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!

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.

zacster said:

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.

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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.

REvvy said:

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...

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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!

FireBrewer said:

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

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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...

It doesn't surprise me that a draught brew tastes different than a bottled. But it does sound like the bottles were bad. Last night I opened a Chimay Cinq Cents and my wife immediately complained. I took a sip and found it way off from the usual Belgian. Waaay too bitter.

As for my original question, I wasn't really trying to do a diacetyl rest, just that the weather forced it on me. But I've read up on it a bit since and some say to do it when fermentation isn't fully done, others say to do it when it is complete. I hit it before fermentation finished. I didn't taste anything off from my hydro sample, so I'm OK I guess.

Next year I'll start my lager in January, so I have better temp control. But even then, I was riding my bike in shorts in January last year, so you never know.

zacster said:

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.

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How come your temp changes so much. Is your beer just exposed to the weather temp swings. I ask this because I lager ferment using a cold basement room(50F/10C) but plan to take the carboys out to the garage for lagering. I will put them into an old UNplugged refrigerator. Hoping the fridge insulates to keep temp swings in check. Average daily temps for March are in the low 30's so if the beer is insulated it should be fine. That's what I'm thinking....

Diacetyl in the bottle can happen when it is primed with fresh wort or kraeusen. I had that happen once but it went away after a while.

Kai

-I'm having network trouble today, causing me to double post occasionally-

balto charlie said:

How come your temp changes so much. Is your beer just exposed to the weather temp swings. I ask this because I lager ferment using a cold basement room(50F/10C) but plan to take the carboys out to the garage for lagering. I will put them into an old UNplugged refrigerator. Hoping the fridge insulates to keep temp swings in check. Average daily temps for March are in the low 30's so if the beer is insulated it should be fine. That's what I'm thinking....

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The beer is in a pantry by the back door of the house. It has no heat of its own. If I close the doors to the kitchen and bathroom that are off of it, it will stay relatively cold. It isn't a basement though, so it will warm up if the outside gets warm, especially since the pantry is actively used. My basement has the boiler for the house so it doesn't stay cold enough.

Meanwhile, it is 25 degrees outside today, with a foot of snow. We thought winter was over last week...

zacster said:

The beer is in a pantry by the back door of the house. It has no heat of its own. If I close the doors to the kitchen and bathroom that are off of it, it will stay relatively cold. It isn't a basement though, so it will warm up if the outside gets warm, especially since the pantry is actively used. My basement has the boiler for the house so it doesn't stay cold enough.

Meanwhile, it is 25 degrees outside today, with a foot of snow. We thought winter was over last week...

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You probably already know this but I wrap my carboy in an old sleeping bag to help with temp swings.

Another question about my brew. I checked last night and the temp had fallen down to 42 in the carboy and all fermentation stopped. I took a reading and it was still at 1.020. Its been 2 weeks now and I'd like to get this finished so I can do my next brew. Should I bring the carboy into a warmer part of the house? Or should I just let it finish out the week where the forecast is for much more spring-like temperatures? What would be the best temp to finish this off? I've read where people will bring a lager up to finish the fermentation, aside from the diacetyl rest.

Any advice?

zacster said:

Another question about my brew. I checked last night and the temp had fallen down to 42 in the carboy and all fermentation stopped. I took a reading and it was still at 1.020. Its been 2 weeks now and I'd like to get this finished so I can do my next brew. Should I bring the carboy into a warmer part of the house? Or should I just let it finish out the week where the forecast is for much more spring-like temperatures? What would be the best temp to finish this off? I've read where people will bring a lager up to finish the fermentation, aside from the diacetyl rest.

Any advice?

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+1 My room got down to 44F/7C and fermentation stopped. I was running late for work this morning so I left it. 2 options: leave it,as temps are expected to go up in the next few days or move it. Not certain which is the best way to go but I think we will have to swish it a little when temps go up.
If I see no change when I get back from work I will relocate it to a warmer area. You might also open the door to the room to let in a little more heat, just thought of this. I should have done this as well.

Unfortunately letting the heat into the pantry lets the cold out into the house. My wife always closed that door even before I used it as a cold fermentation room.

I think I'll leave it for later since I have to leave for work now also. Temps near 60 this weekend so if I do nothing it should work out.

I came home from work early and opened up the door to let the beer warm up a bit, and now it has slowly come back to life. It is only at 44, but it is already starting to bubble again.

zacster said:

I came home from work early and opened up the door to let the beer warm up a bit, and now it has slowly come back to life. It is only at 44, but it is already starting to bubble again.

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I pulled mine out of the cold room just now. It is at 44F and is doing nothing. Will check again in the AM. I think the new area is around 55F.

I looked this morning and there is a layer of foam on top now and the temp is around 50. I didn't stir the yeast or do anything else to get it going.

By midday mine was back to doing its thing. Very happy @ 51F. Going back into the room tomorrow as temps are beginning to rise.

The gravity continues to drop slowly. Last night it read 1.018. The hydro sample tasted pretty good. Today it is supposed to be around 60 and warmer tomorrow. I was hoping that the fermentation would finish so I could transfer to the secondary to lager.