Parallel ferment and Diacetyl Rest

[stevemc32]

Questions for the lager brewers.

I've got two beers in the ferment fridge right now at 11 degrees. The first one, a bock using WY2487 Hella Bock (which recommends a diacetyl rest) has been in the fridge for 11 days and is ready for the increase in temp. The second one is a Boh Pils using WY2000 Budvar and has only been fermenting for 3 days but was a big solid pitch and is well underway.

My understanding of the diacetyl rest is that you only need to increase by a couple of degrees for a day or two for it to be effective. This would take it up to 13 degrees which is the upper limit specified for both yeasts by the manufacturer.

The first question is whether bringing the temp up to 13 degrees for the bock would have any significant effect on the pils in it's earlier fermenting stage? The second question is would the bock need to go straight to lagering temps after the diacetyl rest or would it be ok to bring the temp back down to 11 degrees and wait for the pils to ferment out?

The current plan is to wait out the ferment on the pils, cold crash both for a few days, transfer to keg for lagering.

Cheers,
Steve.

 

[aaronpetersen]

Just take the bock out of the ferment fridge and allow it to warm up a little at ambient temps. Depending on where you live ambient temps at the moment should be about right for a diacetyl rest.

 

[Beertard]

If your waiting out the pills anyway why not just do a rest when there both ready? It's only another week or so then as you say cold crash together and keg.

 

[sponge]

Could you let the bock raise at ambient whilst the pils still kicks on in the fridge?

Or just leave them both til the pils is ready for a d-rest and raise then chill them both? Not ideal for a d-rest after reaching FG with the bock, but could be an option?


EDIT: Beaten by two posts which cover all of mine.

 

[danestead]

Slightly off topic, however id be keen to see how your budvar lager brew goes. I did one of these a few months ago and copped diacetyl even after following good procedues.

As for your question, Im not a very experienced lager brewer but id be tempted to pull the bock out of the fridge and leave it inside your house for a couple of days then put it back in the ferm fridge and wait for the boh pils to finish.

edit. What they said

 

[stevemc32]

Yeah, leaving it in there and waiting for the pils to be ready for a diacetyl rest would be the easiest option but I thought it was only effective prior to reaching final gravity.

Might be an option under the house where the temp stays fairly constant but inside or outside the temp tends to swing about 10 degrees over 24 hours.

 

[Beertard]

Yeah, leaving it in there and waiting for the pils to be ready for a diacetyl rest would be the easiest option but I thought it was only effective prior to reaching final gravity.

So a question, when is the best time to perform an effective diacetyl rest?

 

[stevemc32]

I'm new to lager yeasts so my information was from Palmer's book and states the diacetyl rest should happen about 3/4 of the way to final gravity.

 

[Beertard]

That's always good information, what's the temperature under your house?

 

[stevemc32]

It's 15 degrees at the moment which would work fine but it'll probably get down to about 8 overnight.

 

[Goose]

The second question is would the bock need to go straight to lagering temps after the diacetyl rest or would it be ok to bring the temp back down to 11 degrees and wait for the pils to ferment out?

The current plan is to wait out the ferment on the pils, cold crash both for a few days, transfer to keg for lagering.

A diacetyl rest is good practice but you can also test whether you in fact need one... have a read

 

[stevemc32]

Thanks Goose, that's good info.

The Wyeast specs for the yeast indicate that a diacetyl rest would be necessary so I'm just following those recommendations. I might try that test on the Boh Pils that's also underway now.

Ended up moving the fermenter out of the fridge to under the house and the temp ranged overnight from 16 down to about 13.5 so pretty much spot on for the rest. I'll leave it there for another day or so then back into the fridge to wait out the Pils.

Thanks for the help.