d-rest advice please

[The-Engineer-That-Brews]

I've got a Vienna lager in the FV that is ticking along at 12ºc with OYL-111.
After 4 days it's down to 1030 (OG 1052).

Q1: is it worth doing a d-rest?
Q2: at what SG should I start raising the temp? (e.g. I was thinking 1020)
Q3: what temp should I let it come up to? (bearing in mind the recommended temp range for OYL-111 is 9-13º)
Q4: once it's hit FG should I start lagering straight away?

Many thanks for any advice as I don't have much experience doing lagers :-)

 

[Brewnaldo]

I'm going to watch this thread, as I am entering an intensive lager phase and not hugely experienced in cold fermenting myself.... However, just to let you know what I am currently doing rightly or wrongly.... Fermented my current lager at 11.5 degrees. After 8 days I checked and it had reached 1.010, I have raised it up to 18 degrees where I intend to leave it until Monday, after which point it will be cooled down as far as my ferminator will go. FWIW, I didn't taste any diacetly in the sample, but nevertheless, a few days at 18 cant hurt. Belt and braces et cetera....

 

[Redwulf]

My understanding is that the diacetyl rest takes place after Final Gravity has been reached and needs to be up around 18-20c to allow the yeast to absorb the diacetyl.

 

[thegrantickle]

Diacetyl rest isn't strictly necessary if you are not filtering/fining/pasteurising the beer. The yeast will clean up diacetyl on its own with an extended lagering period. That said, increasing the temperature slightly will encourage this activity. Increase the temperature slowly when you are about 3 days away from your expected final gravity. Cold fermentation is intended to suppress ester/phenol formation from lager yeasts, predominantly produced during the growth phase, and you will be well past that by then - however, a quick increase in temperature could stress the yeast and result in the same unwanted compounds. I would take it up to 14C over a few days and hold it there for 3 or four before your next step, whether that's bottling/cold crashing/conditioning. Hope that helps.

 

[An Ankoù]

My understanding is that the diacetyl rest takes place after Final Gravity has been reached and needs to be up around 18-20c to allow the yeast to absorb the diacetyl.

That's my understanding, too.

 

[MrRook]

The first step should be to determine if you actually need a d-test.

 

[The-Engineer-That-Brews]

The first step should be to determine if you actually need a d-test.

Thanks - how though?
From what I've read you can't do it just by tasting a sample because you won't be able to taste the diacetyl precursors

 

[The-Engineer-That-Brews]

Diacetyl rest isn't strictly necessary if you are not filtering/fining/pasteurising the beer

Thanks TGT - is that because the fining agents will take the yeast out of suspension so they can't finish the job? I used Irish moss in the boil and NBS Clarity when I pitched; so do you think that counts?

 

[thegrantickle]

Thanks TGT - is that because the fining agents will take the yeast out of suspension so they can't finish the job? I used Irish moss in the boil and NBS Clarity when I pitched; so do you think that counts?

Yes, and no. I'm only talking about cold side fining agents.

 

[Green Tiger]

Here’s a fermentation profile I run with for lager brewing. It’s been used to produce pilot batches for lagers that are now commercially available (or about to be) in Australia. It works incredibly well and you won’t get any signs of diacetyl at all.
Initial ferment phase at your desired temp, let’s say 12oC.
2/3’s the way through ferment - in this case probably around 1.024 - start to raise the temp slowly to 18oC. 2oC per day. Hold at 18oC for 3-4 days until no signs of diacetyl and then gradually cold crash to the lowest temp you can. Closer to zero the better. Lager for as long as you can hold out, 3 weeks is good, add finings and package.

 

[HarryFlatters]

I don't check gravity during fermentation (lazy, I know). My normal lager schedule is 1 week at 12C, then raise the temp by 1 degree per day until it's at 18C, leave it for 3 days, then cold crash as cold as my fridge will get.

 

[Dorst]

A diacetyl rest is a good plan for beers that are cool fermented. I tend to play it a bit more safe than most her and ferment at 12c for 12 days, then let it rise to 18 or 19 degrees for 2 days before cool crashing and packaging. I once ramped up the temperature after about 7 days and I noticed that it had some more esters than I wanted.

 

[DuncR]

I’m currently fermenting at 12.5 degrees with MJ M84 yeast. This has a temperature range of 10-15 degrees. If I subsequently take it up to 18 for a d-rest, will this hinder or even kill the yeast?

 

[Brewnaldo]

I’m currently fermenting at 12.5 degrees with MJ M84 yeast. This has a temperature range of 10-15 degrees. If I subsequently take it up to 18 for a d-rest, will this hinder or even kill the yeast?

No it will be fine

 

[gyurmaember]

I'm experimenting with very low fermentation temperatures at the moment. If you have enough time for lagering, the yeast will take care of the diacetyl (if it's present) anyway. Check out the utopian brewing video in the malt miller's YouTube channel.

 

[Brewnaldo]

I'm experimenting with very low fermentation temperatures at the moment. If you have enough time for lagering, the yeast will take care of the diacetyl (if it's present) anyway. Check out the utopian brewing video in the malt miller's YouTube channel.

How low?

 

[gyurmaember]

6 degrees

 

[Brewnaldo]

6 degrees

Cripes. Il need to check out that video I'm intrigued

 

[chthon]

Yes, the diacetyl rest is actually for people who don't have patience for real lagers (and they will fine them too).

The original lager beers were after fermentation stored for at least three months, for clearing and removal of by products.

Check out the product you get in this video, at 5:48 ;-)

As a small boy in the 70's, in Flanders, in a small rural village, I associated the beer then (mostly Stella Artois) with old men (farmers) in black clothes, at the café after mass, it never interested me.

But when I saw "The Beer Hunter" and the product he displayed in the former video, I knew I was right: that was the real product. That looked good.

 

[DuncR]

Yes, the diacetyl rest is actually for people who don't have patience for real lagers (and they will fine them too).

The original lager beers were after fermentation stored for at least three months, for clearing and removal of by products.

Check out the product you get in this video, at 5:48 ;-)

As a small boy in the 70's, in Flanders, in a small rural village, I associated the beer then (mostly Stella Artois) with old men (farmers) in black clothes, at the café after mass, it never interested me.

But when I saw "The Beer Hunter" and the product he displayed in the former video, I knew I was right: that was the real product. That looked good.

Darn, video blocked in uk due to copyright