Diacetyl Rest For Doppelbock

[jasonharley]

I am currently brewing an AG Doppelbock at 12 Deg C... I just put it down in my brand new fridgefermenter and Tempmate that the sparkie wired up yesterday. I have read conflicting opinions on the temperature schedule for brewing doppelbock. Some say 2 weeks in primary and 4 weeks in secondary at 10-12 deg C followed by traditional 0 deg C lagering. Others say that a diacetyl rest is needed at 18 deg C on day 3. I want to make a good Bock and I am prepared to rack and condition at low temp for how long it takes, but I really want to free up the fermenter asap so I can make more lawnmover lager ...... I have drank 3/4 of corney in less than 2 weeks and need more beer... in fact I am getting thirsty thinking about it !!!! Any thoughts ??? ... Heeelllppp!!!!!

5 Eyes

 

[argon]

It all depends on what yeast you're using to be honest.

 

[jasonharley]

It all depends on what yeast you're using to be honest.

I am using a swiss lager yeast

 

[eamonnfoley]

Depends if you pitched low or high, size of pitch, health of yeast, etc. Have a look at braukaiser.com for some quality information on german lager brewing.

 

[jasonharley]

Depends if you pitched low or high, size of pitch, health of yeast, etc. Have a look at braukaiser.com for some quality information on german lager brewing.

It is a bottom pitch .... in fact I just checked the cake and it is at least an inch thick on the bottom after a 1.5 days of fermenting. It was a 12g dry yeast pitch that I obtained from crafterbrewers (I told them what I was brewing and they gave me that). It was refrigerated vac sealed and stored well. The fermenter is currently bubbling at about once every 10 - 15 seconds. Thanks for the advice on braukaiser ...... i had a quick look and it is packed with info

5 Eyes

 

[raven19]

I sampled a fellow brewers Dopplebock last night, which apparently had some diacetyl early on in the bottle, but now after a few months it is gone totally and we could not detect it in our bottled samples.

 

[Goofinder]

I sampled a fellow brewers Dopplebock last night, which apparently had some diacetyl early on in the bottle, but now after a few months it is gone totally and we could not detect it in our bottled samples.

That beer had acetaldehyde, not diacetyl (at least that's what it tasted like to me when it was first bottled). It also wasn't lagered, just 2 weeks primary and 2 weeks secondary or thereabouts in the garage at ambient temperatures (~9-16 degrees, winter in Adelaide).

Fro this beer you'll probably need to let it ferment for 2-3 weeks at 12C, then when it's almost done I would bring it out of the fridge to warm up (diacetyl rest) if you want. Then rack and lager for a while if you can handle the wait. A diacetyl rest on day 3 would be useless and probably just result in more off-flavours.

 

[jbirbeck]

T
Fro this beer you'll probably need to let it ferment for 2-3 weeks at 12C, then when it's almost done I would bring it out of the fridge to warm up (diacetyl rest) if you want. Then rack and lager for a while if you can handle the wait. A diacetyl rest on day 3 would be useless and probably just result in more off-flavours.

+1

 

[mxd]

It is a bottom pitch .... in fact I just checked the cake and it is at least an inch thick on the bottom after a 1.5 days of fermenting. It was a 12g dry yeast pitch that I obtained from crafterbrewers (I told them what I was brewing and they gave me that). It was refrigerated vac sealed and stored well. The fermenter is currently bubbling at about once every 10 - 15 seconds. Thanks for the advice on braukaiser ...... i had a quick look and it is packed with info

5 Eyes

what temp was the work when you added the yeast, i.e put it in, the temp was 18 then added yeast, over the next day it was down to 12.

If this is the case then I would do a D-Rest.

But the best thing to do is take a hydro reading around day 6, if it has a buttery flavour/aroma (and is abuot 2/3rd of the way through fermentation) then ramp up the temp to 16 - 18 to complete fermentation, then when fermentation done, drop the temp down to 2 for a couple of weeks, then keg and leave it for another couple of weeks.

good luck

N.B, the last lager I did didn't have a d-rest and it's now like popcorn

 

[brendo]

what temp was the work when you added the yeast, i.e put it in, the temp was 18 then added yeast, over the next day it was down to 12.

If this is the case then I would do a D-Rest.

But the best thing to do is take a hydro reading around day 6, if it has a buttery flavour/aroma (and is abuot 2/3rd of the way through fermentation) then ramp up the temp to 16 - 18 to complete fermentation, then when fermentation done, drop the temp down to 2 for a couple of weeks, then keg and leave it for another couple of weeks.

good luck

N.B, the last lager I did didn't have a d-rest and it's now like popcorn

This is good advice - technically, a d-rest only really needs to be employed if diacetyl is present... if you do take a hydro sample, make sure you let it warm up to room temp as this will help make the compound more evident. Depending on the level of diacetyl (assuming it is present) it will taste anything from caramel -> buttery -> butterscotch.

All this aside, it is not a bad practice to raise the fermenting temp of a beer (ale or lager) slightly towards the end of fermentation just to help it clean up a bit, so as an insurance policy it wouldn't be a bad idea to ramp the temp up a few degrees just to be safe.

 

[jbirbeck]

This is good advice - technically, a d-rest only really needs to be employed if diacetyl is present... if you do take a hydro sample, make sure you let it warm up to room temp as this will help make the compound more evident. Depending on the level of diacetyl (assuming it is present) it will taste anything from caramel -> buttery -> butterscotch.

All this aside, it is not a bad practice to raise the fermenting temp of a beer (ale or lager) slightly towards the end of fermentation just to help it clean up a bit, so as an insurance policy it wouldn't be a bad idea to ramp the temp up a few degrees just to be safe.

technically yeah a d rest is only needed if its there but a lot of people can't pick it so how would you know? I certainly wouldn't have and then handed it over to someone more in the know so proud of my brew and they say 'its no good'

Lagers I like to pull out of the ferment fridge to warm up at the end of the ferment, I'll then rack it and get it into secondary where it will get chilled down for some CCing. But thats mostly because that is what works for my set up.

 

[brendo]

technically yeah a d rest is only needed if its there but a lot of people can't pick it so how would you know? I certainly wouldn't have and then handed it over to someone more in the know so proud of my brew and they say 'its no good'

Lagers I like to pull out of the ferment fridge to warm up at the end of the ferment, I'll then rack it and get it into secondary where it will get chilled down for some CCing. But thats mostly because that is what works for my set up.

agreed... hence my "insurance policy" comment around it being good practice for beers in general.

Generally speaking, diacetyl is produced by most yeast, it's just that some yeasts are more prone to it and lager strains are often worse and it shows up more as they don't (or shouldn't) have fruity esters or other things that might hide it.

 

[aaronpetersen]

All this aside, it is not a bad practice to raise the fermenting temp of a beer (ale or lager) slightly towards the end of fermentation just to help it clean up a bit, so as an insurance policy it wouldn't be a bad idea to ramp the temp up a few degrees just to be safe.

I agree with Brendo. There's no harm to be done in doing a diacetyl rest, so I always do one with lagers.

 

[raven19]

That beer had acetaldehyde, not diacetyl (at least that's what it tasted like to me when it was first bottled). It also wasn't lagered, just 2 weeks primary and 2 weeks secondary or thereabouts in the garage at ambient temperatures (~9-16 degrees, winter in Adelaide).

:icon_offtopic: My mistake! Whoops. Gee you have a few samplers and forget which word is which...

Pretty tasty beer nonetheless mate.

 

[cdbrown]

After hearing Jamil and Palmer on a podcast this morning they repeated a few times to pitch yeast below normal ferment temp and let it rise up to ferment temp to minimise the precursors to diacetyl. If it's evident then as the ferment shows signs of slowing, warm it up 3-5c and let it ferment out. Crash chill and begin lagering.

 

[MeLoveBeer]

After hearing Jamil and Palmer on a podcast this morning they repeated a few times to pitch yeast below normal ferment temp and let it rise up to ferment temp to minimise the precursors to diacetyl. If it's evident then as the ferment shows signs of slowing, warm it up 3-5c and let it ferment out. Crash chill and begin lagering.

Yeh, Jamils new Yeast book says to pitch 1.5-2 degrees cooler than the ferment temp, allow it to rise natually with the temperature generated from the ferment over the first 2 days, hold the temp till the ferment is between 2/3 and 3/4 finished then finally raise the temp slowly by 2-5 degrees over 2 days to clean it up (and hold it there till done).

Same thing applies for both ales and lagers (just different baseline temp)

 

[jasonharley]

Thanks all for the great advice ... I am going to check SG after Day 6 onwards and D-rest from 12 deg C to 17 deg C at around 80% attenuation regardless ... i come from the "flood city" and I have a new appreication for insurance policies !!!!! By the way the Braukaiser site is an absolutely cracker ..... lots of good scientific stufff in there !!!!!

cheers and thanks again

5 eyes

 

[jasonharley]

what temp was the work when you added the yeast, i.e put it in, the temp was 18 then added yeast, over the next day it was down to 12.

If this is the case then I would do a D-Rest.

But the best thing to do is take a hydro reading around day 6, if it has a buttery flavour/aroma (and is abuot 2/3rd of the way through fermentation) then ramp up the temp to 16 - 18 to complete fermentation, then when fermentation done, drop the temp down to 2 for a couple of weeks, then keg and leave it for another couple of weeks.

good luck

N.B, the last lager I did didn't have a d-rest and it's now like popcorn

Hey mxd

It is Day 7 and i have taken a hydro reading and it is now 1018. When you say you ramp up the temp.... do you simple set the tempmate to 17 deg or do you increase the temp by 1-2 deg every over 3 days?

cheers
5 eyes

 

[jasonharley]

I am now attempting a diacetyl rest on bock

So last night I measured the hydro at 1018 and have raised the temp from 12 deg to 13.5 deg..... tonight I will raise it from 13.5 deg to 15 deg and then Sun night I will raise it to 17 deg and then I will hold the 17 deg for a subsequent few days until the bock is mostly attentuated .... i am guesing that for bock the FG will be around 1012. After that i'll rack it to a secondary cube and lager it at 1 deg for a month.

Can anyone forsee any problems ???...... I can't find any temp raising schedules for discetyl resting bock anywhere.

cheers
5 eyes

 

[Nashmandu]

The Diacetyl rest should not be done on a certain day - day three for example - rather it should be done after the Grav has dropped to a certain point. you need to have enough sugars left for the yeast to eat to drive the temp up, but you dont wont the temp to rise during main part of ferment.

eg O.G of 15, target F.G of say 3. The temp in this situation should be risen at approx 7-10.

Always do diacetyl rest for lagers!!