Diacetyl Rest

[newguy]

i've been getting diacetyl on the nose in my english ales of late, using wyeast esb, now i'm fermenting at 20 degrees, so its a bit hard to raise the temp for a rest?

Some strains are just natural producers. If you use the wyeast or white labs Scottish strain, look out! Give it a bit of extra time on the yeast - maybe a week once it drops out and it should be reduced. Maybe not gone, but reduced. If you want it completely gone, there's not much danger in raising the temp beyond 20C once fermentation is over.

Edit: Could be you have a natural sensitivity to diacetyl too. Most people I know are pretty blind to it, as am I.

 

[gibbocore]

mate you could be right ie the natural sesnsitivity, cause i ask my brother about it and he reckons i'm going mad. I can also usually name all the fruits and spices in a bottle of red before i read the back of the bottle, damned pallet.

 

[buttersd70]

Diacetyl seems to me to be one of those funny flavours, where you're either very sensitive, or very blind to it, with very little middle ground.

 

[matti]

Yep very true.

I seem to detect it as a slick flavour in bigger flavoured beer.
I firmly believe the rest should happen while the yeast is still relative active.
2/3rds of the the way in the fermentation cycle.

Matti

 

[reviled]

Bump...

So the Pilsners been resting for three days now at 18-19*, the SG is down to 1012, but I think its still fermenting...

Question is, what do I do? Do I leave it at 18* till fermentation has finished and then lager? Or should I bring down to 12* for fermentation to finish before lagering? Or should I just stop fermentation myself and go ahead and lager it?

 

[newguy]

Take it down 2C every 12 hours until you get to 2-3C and lager as normal. When it gets down to 2-3C you can transfer again if you like. Just let it lager for 4-8 weeks and bottle/keg. It will continue to slowly ferment and it will be finished when you bottle - no need to worry. You may require a fresh dose of yeast but I've never had problems with my bottles not carbonating even if the beer was crystal clear at bottling.

 

[reviled]

Take it down 2C every 12 hours until you get to 2-3C and lager as normal. When it gets down to 2-3C you can transfer again if you like. Just let it lager for 4-8 weeks and bottle/keg. It will continue to slowly ferment and it will be finished when you bottle - no need to worry. You may require a fresh dose of yeast but I've never had problems with my bottles not carbonating even if the beer was crystal clear at bottling.

Dont you love kegs just for that reason

So will it still slowly ferment at say 2-3*?? Crazy, so I cant just make it crash out like an ale if I want fermentation to stop?

 

[newguy]

If you drop the temperature very abruptly, it will stun the yeast. If that's what you want, drop the temp on your fridge to 2 or 3C now and it should pretty much stop fermenting. Or at least slow way down.

 

[reviled]

If you drop the temperature very abruptly, it will stun the yeast. If that's what you want, drop the temp on your fridge to 2 or 3C now and it should pretty much stop fermenting. Or at least slow way down.

After talking to Screwtop about the mash schedule I used, I dont know if I want to let the yeast run its course as it may end up drier than I wanted... 1012 is good for a Pilsner imo, not too dry for my tastes.. So I may do just that...

Cheers mate :icon_cheers:

 

[jmnug2]

If you are raising the temp for diacetyl rest before the beer has finished fermenting will the yeast not produce some off flavours (ester, etc....). I'm talking about a lager that's been fermented at 11 degrees for a week (OG 1037) now down to 1014, so if I bring it up to 17-18 for the remainder will it have any detrimental effect on the taste?

 

[Phoney]

If you are raising the temp for diacetyl rest before the beer has finished fermenting will the yeast not produce some off flavours (ester, etc....). I'm talking about a lager that's been fermented at 11 degrees for a week (OG 1037) now down to 1014, so if I bring it up to 17-18 for the remainder will it have any detrimental effect on the taste?

No. Given that you only bump up the temperature when most of the fermentation has completed there will be no esters released from the yeast. they generally only happen in the first few days during vigorous fermentation.

 

[Thirsty Boy]

Diacetyl re-absorbtion is about exposure to active yeast... even very slightly active yeast.

Increased temps for D rests are not necessary, they just make things happen faster. The D is both produced (from its pre-cursors) and re-absorbed more quickly. The reason you get higher levels of D with some english yeast strains, is that they are so flocculent that they drop out and go dormant when there is still D to absorb. In the case of an ale, you would be trying to "extend" the active phase of the yeast, rather than simply bump the temp. Lager yeasts will do the trick all the way down to nearly zero degrees... and thats one of the reason why lagers are "lagered" for long periods. If you are going to raise the temp at the end of fermentation, then there is no need for an extensive lagering period - this is exactly why the technique of an slightly higher D rest was developed, to shortcut the time.

There are so many different techniques of lagering, aging, conditioning; of reducing Diacetyl, acetylaldehyde etc - but at the end of the day they all boil down to giving the yeast a chance to do its job. Either for a shorter time at a higher temperature, or for a longer time at a lower temperature.

 

[Mikedub]

G'day brewers
I've got an ale at 1.005 and have diacetyl, I'm blaming the long lag time (30hrs) due to what now seems to be poor a reculture of Coopers PA, its been in primary for 11 days, I'm thinking that the yeast have finished their work and wont be able to reduce it now, is this the case do you think?,
unsure to raise temp, add some yeast to clean it up, leave it another week, or do neither, have a beer and re-read about yeast farming techniques

 

[RdeVjun]

Mikedub, I'd elevate the temperature for a few days- AFAIK it won't hurt anything. So long as there's enough yeast that haven't flocced out, in which case a very gentle rouse might fix the problem.
I'm using my electric hot water system in the laundry for D- rests, gently bumps it up to around 22C for a few days with a jumper and a coat insulating the fermenter, seems to work quite well but I would understand that not everyone has that 'luxury'.

 

[Mikedub]

thanks RdeVjun, shall give it a crack

 

[RdeVjun]

No sweat Mikedub.
It shits me doing D-rests as I suspect I'm one of the unlucky ones (that depends on your POV of course) who are unable to detect the stuff (yet to be confirmed). However I got pinged badly for it last year at the Nats, so I run through this rigmarole as a rule nowadays, particularly in winter.

 

[Bribie G]

I like Diacetyl in its place, but of course you can't go handing out foaming jugs of Butterscotch Lager - According to the new Yeast book if you pitch a wee bit high (normally to counter a rather meagre yeast count to start off with) then you should bring the beer up to that temperature for a few days at the end. Underpitching can be a problem with recultured Coopers yeasts - just did one now and it took forever to culture up so I've dragged it out of the fridge after a week in primary an it's sitting in the garage at 22 degrees (bit warmer here down the Hill than at RdeV's place B)) and there it will sit for a few days.

I've often heard that when re-using yeast from a Coopers style clone, the subsequent brews are a fair bit different from the first one. I have a theory that - rather than the yeast "drifting off style" this is more likely a result of pitching at a good rate in the child brews, as opposed to the often dodgy initial pitch from the bottle culture. I'll certainly be reusing this batch as it took me two goes and around 9 tallies to get a good one going. Yes, had to force myself to drink all that Coopers Sparkling, oh the humanity.

Eddit: Grammatik

 

[a1149913]

I was told that once fermentation is finished the chance for diacetyl rest is over.?

also slightly off topic, but do the coopers pale ale and coopers sparkling beers use the same yeast?

JT

 

[bignath]

also slightly off topic, but do the coopers pale ale and coopers sparkling beers use the same yeast?

As far as i know JT, yep same yeast.

However, most brewers seem to prefer the lower ABV% of pale ale to higher % of the sparkling due to the yeast being in "better condition" or something like that....Not sure i completely believe this, however when reculturing Coopers yeast, i do tend to go for the pale ale, as it is a beer that i prefer over the sparkling.

 

[manticle]

I was told that once fermentation is finished the chance for diacetyl rest is over.?

also slightly off topic, but do the coopers pale ale and coopers sparkling beers use the same yeast?

JT

Same yeast in all coopers ales.

Cleaning of diacetyl will continue while in contact with active yeast so bottle conditioning is included, left on yeast cake post primary is included.