Diacetyl after lagering

[Steverett]

I just sampled my lager that has been in the fridge for almost a month, and was blown away by butterscotch flavor. I'd tasted it at every point in the process and never had a hint of diacetyl, so I was surprised to find it so strong. Is there anything I can do to fix it now?

The beer is a Bock made with wyeast hella Bock yeast. My process is below:

Pitch 2 at starter @ 53F, O.G. 1.064
Primary @ 50F for 11 days
Secondary @ 50F for 12 days, F.G. 1.020
Diacetyl rest @ 65F for 36 hours
Lager at 35F, currently at 24 days

Advice on how to prevent this in the future is also very welcome.

 

[JoeBronco]

Did you wait untill fermantion was starting before crashing to 50*?
Why did you switch to secondary?

Looks like you didnt let it sit in the Diacetyl rest long enough for the beer to absord and fend off the diacetyl. Its still young though. Your beer is still good.


This is a great step by step:

Pitch your yeast in the 60ْF - 65ْF range. When fermentation starts, drop to the recommended temperature of the yeast you are using, this may be as low as 45ْF

Fermentation should take 2 weeks at what ever temp your yeast states (im asuming yours is 50ْF)


Diacetyl rest for 2-3 days (48-72 hours) After fermentation you will want to raise your temperature as close to 62ْF as possible. Diacetyl rest will do three main things;
First, it will assure fermentation is complete.
Second, it will drive off any remaining CO2 that might cause “off flavors”.
Third, it will allow the yeast to absorb the diacetyl produced by fermentation.

LAGER time Rack your beer into a carboy. Slowly lower your temperature about 5ْF a day until you hit 35ْF. You can go colder, but watch your temperatures closely. Lagering has begun! Lager for a minumum of six weeks and don’t be shy. It is not uncommon to lager a bock for up to a year.

 

[rgarcia78147]

I just sampled my lager that has been in the fridge for almost a month, and was blown away by butterscotch flavor. I'd tasted it at every point in the process and never had a hint of diacetyl, so I was surprised to find it so strong. Is there anything I can do to fix it now?

The beer is a Bock made with wyeast hella Bock yeast. My process is below:

Pitch 2 at starter @ 53F, O.G. 1.064
Primary @ 50F for 11 days
Secondary @ 50F for 12 days, F.G. 1.020
Diacetyl rest @ 65F for 36 hours
Lager at 35F, currently at 24 days

Advice on how to prevent this in the future is also very welcome.

Did you take your beer off the primary yeast cake before you did a diacetyl rest?

 

[Yooper]

Did you wait untill fermantion was starting before crashing to 50*?
Why did you switch to secondary?

Looks like you didnt let it sit in the Diacetyl rest long enough for the beer to absord and fend off the diacetyl. Its still young though. Your beer is still good.


This is a great step by step:

Pitch your yeast in the 60ْF - 65ْF range. When fermentation starts, drop to the recommended temperature of the yeast you are using, this may be as low as 45ْF

Fermentation should take 2 weeks at what ever temp your yeast states (im asuming yours is 50ْF)


Diacetyl rest for 2-3 days (48-72 hours) After fermentation you will want to raise your temperature as close to 62ْF as possible. Diacetyl rest will do three main things;
First, it will assure fermentation is complete.
Second, it will drive off any remaining CO2 that might cause “off flavors”.
Third, it will allow the yeast to absorb the diacetyl produced by fermentation.

LAGER time Rack your beer into a carboy. Slowly lower your temperature about 5ْF a day until you hit 35ْF. You can go colder, but watch your temperatures closely. Lagering has begun! Lager for a minumum of six weeks and don’t be shy. It is not uncommon to lager a bock for up to a year.

I don't agree at all! One of the BEST ways to produce a ton of diacetyl is pitching too warm!

A longer diacetyl rest is probably needed, before racking to secondary. 36 hours obviously didn't cut it. Tasting for diacetyl is tricky, because it's only in large amounts that it tastes buttery. In smaller amounts, it's more of an oily or "slick" mouthtfeel. You don't ever want to rack the beer until the diacetyl rest is finished! Ideally, you'd do the diacetyl rest when you're about 75% of the way to FG- or often about 1.020-1.022. That means the yeast is still very active, but the bulk of fermentation is done.

After the diacetyl rest, the beer can be racked and lagered.

It's probably too late to do much about it now, to be honest. How bad is it? If it's not drinkable, you could try making a big starter and repitching, and then racking, and then lagering, etc. But it's probably not worth it unless the beer is undrinkable.

Next time, pitch a bigger starter. A BIG starter. Pitch the yeast in the 40s, and allow the wort to rise up to optimum fermentation temperature, usually about 50 degrees. That will slow/reduce/stop diacetyl production to begin with. Then after about 10 days or when the beer is 75% of the way to FG, raise the temperature to 68 degrees for 48 hours or until there is NO hint of diacetyl and FG is reached. Then rack, and begin lagering.

 

[Yooper]

According to White Labs' Chris White a D-rest should be performed during fermentation when the beer has reach between 2 and 5 gravity points of terminal gravity.

It's a tough call because we, home brewers, don't normally check gravity every day during fermentation.

Personally I brew on Sundays and ferment cold for one week. The following Sunday I will remove the fermenters from the chamber and rest them at 60 to 70 degrees for the following week. After that it's back to cold lagering until secondary (yes Revvy, I use a secondary so don't shoot me). Every beer that I brew that is not a wheat gets racked to secondary on gelatin.

I don't have a set schedule, but I'd agree that a week to 10 days is a long enough primary for a lager IF a big enough starter is used.

I differ from the Dragon in that I never use gelatin. (Many of us old hippies are vegetarians! I'm not but many friends are!).

There a couple of keys here- one is minimizing diacetyl production in the first place. Fermenting at the proper temperature (not starting high and reducing the temp), pitching enough yeast, and making sure to do a thorough diaceytl rest after or at the end of primary.

 

[JoeBronco]

I don't agree at all! One of the BEST ways to produce a ton of diacetyl is pitching too warm!

Not that i want to go against your wealth of knowlage Yooper...

Pulled that bit of info from the from the Brewing network's podcast on 9/2005 called "Lagering". Here is a link to the Podcast. TONS of information!

http://www.thebrewingnetwork.com/shows/The-Sunday-Session/The-Sunday-Session-09-25-05-Lagering



From my experience as long as you get the temp down before the fermentation creates krausen your fine. But i really dont have all that much hands on experience with lagering, just from books and podcasts and the few batches i have made. Its an old podcast so thing might have changed and been redefined from then until now.

 

[KAMMEE]

Joe, if you listen to that podcast you'll note that Jon likes pitching warm (65) then bring the temp down to 50. Jamil has always been a proponent of Yooper's method, pitch cold (around 43-44) and let it naturally rise to 48-50 and hold. A more appropriate podcast that provides more technical guidance can be found in the Brew-Strong list of shows as Jamil and John Palmer discuss lagering there too. I would say the safer source is the the Yeast Book. The reason a lot of us like to pitch cold and let rise is because we A) have the capability to make a healthy, clean starter which provides enough yeast so that we need less growth at the start, and B) it is a method that almost to ensures a cleaner tasting beer because the yeast don't grow as fast and the ferment is slower and longer but produces less diacetyl and other undesired esters as long has you have some temp control to keep it at 50. The Yeast book put out by Chris White and Jamil confirm, along with other sources note that during fermentation, the yeast are producing esters and byproducts which contribute to the flavor of the beer. Some of these are re-absorbed later in the ferment, (in this case a D rest). However, on Page 97, under fermentation temperature control, here is a quote: "When working with a proper pitch of yeast, the optimal starting temperature for the majority of fermentations is just a couple degrees (1-3F) below your target fermentation temperature."

 

[Steverett]

According to White Labs' Chris White a D-rest should be performed during fermentation when the beer has reach between 2 and 5 gravity points of terminal gravity.

It's a tough call because we, home brewers, don't normally check gravity every day during fermentation.

Yeah, the large amount of foam and krausen made it hard to measure too. And I ferment in a bucket so I can't see inside easily. Also, 2 to 5 points is how far off my FG prediction usually is anyway.

 

[Steverett]

It's probably too late to do much about it now, to be honest. How bad is it? If it's not drinkable, you could try making a big starter and repitching, and then racking, and then lagering, etc. But it's probably not worth it unless the beer is undrinkable.

It tastes like a Werthers. I might have to do that, unless it will improve with more lagering.

My original starter was only 2 qt because that was the biggest vessel I had for it.

EDIT: On second thought, I just realized that I have an Oktoberfest lager that will be going into secondary shortly. I think I'll just rack the bock onto the yeast cake from that and then re-lager after letting it go for a few days. I'll put an update if this works.

Also, I tasted it again last night and it seemed much less strong; since I am lagering in a keg, I guess my first taste had a lot of yeast.

EDIT 2: P.S. Thanks for the replies, everybody. This was my first lager, so I had no idea about how the flavors can change during lagering. My experience with ales has been that off flavors during fermentation diminish over time, not increase. I'll take the advice in this thread into account for future brews.