Can I perform a diacetyl rest while naturally carbonating in the keg?

[jordanfrenzy]

I have started using sugar and carbonating naturally in the keg. I generally complete my 10-14 day primary with ales and then give them a week at room temperature to get mostly carbed up.

My question is, can I ferment a lager at 48 for 10-14 days (or whatever your lager schedule might be) and then perform the Drest with added sugar in the keg?

 

[jekeane]

https://www.whitelabs.com/sites/default/files/Diacetyl_Time_Line.pdf

This would lead me to say in general no. The yeast will continue to consume the diacetyl after they have consumed your priming sugar assuming you give adequate time.

Proper pitch rate, nutrients should in theory keep diacetyl below perceivable thresholds.

 

[ESBrewer]

I would keep it in the primary, without additional sugars when doing the rest. It won't really take that long when the beer has warmed up to something like 65-70F. 2-3 days could be enough. If you remove most of the yeast (while transferring from primary to keg), it will become very slow or even impossible to get rid of a high diacetyl concentration. The pressure that forms during carbonation will also slow down yeast metabolism (probably by interfering with transport of many kind of compounds through cellular membrane). As a result, it is probably not going to be any faster or more convenient to wait for the diacetyl reduction in the keg post carbonation.

 

[homebrewer_99]

The beer has to be warm (a relative term) during the D-rest.

I kegged a Speed Brew one time and a week later it had diacetyl.

I pulled it out of the keezer, dumped the pressure, removed the lid, dumped in some Notty yeast, replaced the lid, removed the gas in post and put an airlock on it (with a 1" length of tubing to hold it in place on the threads). Left it at room (garage) temp for a week and it was all gone.

I put it back in the keezer and gassed it up for a week.

No problems after that.

 

[mabrungard]

I'm doing just what the OP mentions for a Maibock I'm brewing. I transferred the beer to a keg when it still had about 4 points of gravity left and left the keg in my ambient basement for a D-rest. That beer used the S-189 dry yeast, so I'll see how it performed with respect to diacetyl production or cleanup in a week or so.

The whole idea in kegging with sugar or before terminal gravity is to naturally carbonate and reduce oxygen contact with the finished beer.

 

[jordanfrenzy]

I would keep it in the primary, without additional sugars when doing the rest. It won't really take that long when the beer has warmed up to something like 65-70F. 2-3 days could be enough. If you remove most of the yeast (while transferring from primary to keg), it will become very slow or even impossible to get rid of a high diacetyl concentration. The pressure that forms during carbonation will also slow down yeast metabolism (probably by interfering with transport of many kind of compounds through cellular membrane). As a result, it is probably not going to be any faster or more convenient to wait for the diacetyl reduction in the keg post carbonation.

Excellent answer. Thank you.

 

[Yooper]

I'm doing just what the OP mentions for a Maibock I'm brewing. I transferred the beer to a keg when it still had about 4 points of gravity left and left the keg in my ambient basement for a D-rest. That beer used the S-189 dry yeast, so I'll see how it performed with respect to diacetyl production or cleanup in a week or so.

The whole idea in kegging with sugar or before terminal gravity is to naturally carbonate and reduce oxygen contact with the finished beer.

Can you remember to report back? I haven't used dry lager yeast, and am interested in how it does for a maibock.

Once it's done, I assume you're pushing it to a serving/lagering keg?

 

[FermentedCulture]

Without the addition of sugar, if you were to capture the last ~2 points of extract you would more or less be doing cask conditioning.

With the addition of sugar you are more or less doing cask conditioning with sugar addition (cask refermentation), in other words similar to bottle refermentation.

The addition of sugar into mature beer will actually make the yeast go into another growth cycle, this produces more diacetyl but more often than not leads to less diacetyl after it has finished in comparison to the mature beer - at least in the case of bottle refermentation.

Since it's a lager perhaps there's information on this on some German websites to do with keg/cask conditioning of kellerbier.

 

[FunkedOut]

If I read the OP correctly, the primary fermentation is complete and the beer is then transferred to a keg and sugar added for a secondary fermentation.
This would be more like krausening than spunding.
No experience, but I’ve read that krausening can be effective at removing diacetyl. I’ve also read that it can add to it, if done wrong. I guess the yeast will produce some, and then hopefully suck up more than produced.