Delayed Diacetyl Appearance In Lager

[Bizier]

That is a decent summary Goose. I've not heard of the enzyme, but diacetyl should not really represent a formidable enemy. Just do a test and work out how much will eventually form, then rouse/rest warm til it clears.

You don't need to do all of the chilling etc if you can learn to detect vdk in warm samples.

 

[waggastew]

Listened this week to a Brewing Network podcast where Mike McDole described a 'short' lager ferment. Focus was on keeping the yeast really active by progressively raising the temp throughout the ferment. Notes (temp in F) are below, basically use the SG as the guide. It got my interest as I have been doing the fake lager/US05 things because I got the shits with trying to eliminate faults due to the ferment.




I pitch and oxygenate at 55F and hold until the gravity drops 50% of the way to terminal gravity (For example, if my OG is 1.052 and I expect to finish at about 1.010, then a drop of .021 gravity points would be 50%.)

I then raise the fermentation temperature by 3 degrees to 58F and hold until the gravity drops 75% of the way to terminal gravity.

I then raise the fermentation temperature by 4 degrees to 62F and hold until the gravity drops 90% of the way to terminal gravity.

I then raise the fermentation temperature by 4 degrees to 66F and hold until I reach terminal gravity.

With this method, 75% of the fermentation takes place at 58F or below, 90% at 62F or below.

Tasty

 

[Bizier]

Ascending ferment profile based on gravity is how the bulk of commercial lager is produced.

 

[citizensnips]

Quick question without starting a new thread. How is it people say when you do a diacetyl rest you have to lager right after and to do a diacetyl rest you should be 80% terminal gravity, so say your beer ferments in 7 days but you like to let it go in primary for two weeks before chilling and lagering...what the hell do you all do?
Ferment for a week or so, d rest then lager or let it fully ferment as much as it will at lager temp, d rest then lager. Thoughts?

 

[dent]

When D-rest is complete, primary ferment is complete anyhow. Gravity counts more than time in this regard. I think it is fairly critical to have some fermentables left when commencing D-rest - if you miss the boat, sucks to be you.

 

[Bizier]

Depends what you are after, there is no "right" answer unless you specify your particular needs like preserving yeast viability for repitching or turnaround requirements. Some people have preferences based on traditions.

 

[Goose]

That is a decent summary Goose. I've not heard of the enzyme, but diacetyl should not really represent a formidable enemy. Just do a test and work out how much will eventually form, then rouse/rest warm til it clears.

You don't need to do all of the chilling etc if you can learn to detect vdk in warm samples.

hey fella thanks.

My issue is not being able to detect vdk (the class of compounds that diacetyl falls under), rather its being able to detect the flavourless ******* precursor AAS.. the only way to do this is to accelerate the conversion of this compound to diacetyl. I've just done the test on a batch I have and I've identified I seriously do need a rest on this particular brew....its full of AAS. I'll raise from ferment temp which is 10 deg C (Wyeast Danish Lager) to 18 deg C and rest for 3 days then do the test again.

What this tells you is whether you really need to raise the fermenation temperature before racking or not...

Think i will start a new thread on this mystery enzyme I came across for a bit of debate.

 

[Bizier]

Sorry, I meant you don't need to cool your forced AAL conversion samples after heating if you can pick vdk in a hot sample. I'm just trying to sell the potential simplicity of the test. I'm amazed when I get commercial beers that have diacetyl, it is really inexcusable.

 

[Goose]

Sorry, I meant you don't need to cool your forced AAL conversion samples after heating if you can pick vdk in a hot sample. I'm just trying to sell the potential simplicity of the test. I'm amazed when I get commercial beers that have diacetyl, it is really inexcusable.

You are right mate, you dont really need the "control" sample.

I could not detect any vdk in the sample ex fermenter though it had reachedFG. I put half glass of it covered with cling film into a hot water bath for 10 mins. When I removed the film I could actually smell diacetyl at a 1000 paces, I find it more detectable in the nose than taste buds somehow....

 

[Mardoo]

Which leads me to this idea... there is an enzyme available to the brewing industry that eliminates the diacetyl formation step completely. Branded "Exalase". Nice to give this a shot as it would seem to solve the need for a diacetyly rest, but have not heard of it being available anywhere.

Anybody head of this stuff ?

We had a chemist come to the last Melbourne Brewers meeting to talk about enzymes in brewing and he mentioned Exalase, (among many others). He said he'd see about samples or supply of some of the different ones for us. I'll see what I can find out at this Wednesday's meeting.

 

[Goose]

We had a chemist come to the last Melbourne Brewers meeting to talk about enzymes in brewing and he mentioned Exalase, (among many others). He said he'd see about samples or supply of some of the different ones for us. I'll see what I can find out at this Wednesday's meeting.

Would appreciate the feedback post meeting

Seem the other thead I started on this got infected by the sexually dysfunctional troll thats been trying to impress us with his one liners since he registered last month to get his post count up