Diacetyl, Racking & Lagering Process.

[huscre]

Hi Guys,

I'm just looking for some clarification since I've never actually lagered a lager before...

I have a czech pilsener that's currently fermenting at 9 degrees in a fridge and I want to give it all the attention it deserves to taste right.

My current plan is to let it ferment at 9 degrees for ~2 weeks, raise the temp to 18 degrees for 2 days (for diacetyl) then hopefully keg it and stick it in my keg fridge at ~4 degrees for lagering for as long as i can control myself from drinking it.

Have I got the order right? or have I mixed up the diacetyl/lagering process?

Also am I correct to rack before raising the temp to 18degrees, or does it need to be sitting on the yeast to get rid of the diacetyl?

Also, can I have it carbonated while it's lagering?

 

[manticle]

That's the right order. I think there'll be enough yeast to clean up if you rack first. Someone else may have more information.

Not sure about the kegging issue as I bottle.

 

[huscre]

Cheers Manticle.

:icon_offtopic: PS. Congrats on your DIY AG batches!

 

[manticle]

Cheers. I have a czech pilsner which has been racked and is coming up to diacetyl temp at the moment too (racked tonight) so I hope for both of us that my info is correct (and all the people at the vic case swap).

 

[Brewman_]

Hey fellas,
I have the czech pilsner going too Just started 3 days ago, so early days. I have had a few issues getting the kegged beer nice and clean so was planning on a maybe a 3 day diactyl rest?

Are you going to force carb your keg Huscre?

As for racking, not sure? I am not planning to at that stage.

Fear_n_Loath

 

[loikar]

Hey fellas,
I have the czech pilsner going too Just started 3 days ago, so early days. I have had a few issues getting the kegged beer nice and clean so was planning on a maybe a 3 day diactyl rest?

Are you going to force carb your keg Huscre?

As for racking, not sure? I am not planning to at that stage.

Fear_n_Loath

24 hours usually does the trick, 3 days might impart flavours you dont want as lager yeast doesn't like a high temp...you dont want them eating their mates.

But then, ive had 3 chimays and a doppelbock tonight and am pretty blissed out...so yeah, beer ahoy!

 

[Brewman_]

24 hours usually does the trick, 3 days might impart flavours you dont want as lager yeast doesn't like a high temp...you dont want them eating their mates.

But then, ive had 3 chimays and a doppelbock tonight and am pretty blissed out...so yeah, beer ahoy!

OK BeerFingers
So would you take it straight down to lagering temps after that?

Thanks, Fear_n_Loath

 

[Adamt]

It won't "impart flavours" after fermentation is done. It won't "eat its mates" unless you leave it for weeks, even months. A diacetyl rest isn't always necessary (especially if there's no diacetyl!) but it can also help finishing off fermentation. 1-2 days is enough for a diacetyl rest though.

And huscre: It doesn't really matter when you do a diacetyl rest unless you sterile filter... yeast will be in suspension in the beer and the yeast in suspension is what will clean up the diacetyl.

 

[Brewman_]

Thanks Adamt,

I will give it a day or so.

Fear_n_Loath

 

[manticle]

OK BeerFingers
So would you take it straight down to lagering temps after that?

Thanks, Fear_n_Loath

It's often recommended to drop the temp slowly so as not to shock the yeast. Some recommend a couple of degrees per day. That might be a bit anal and finicky- with my current brew I plan on just putting the fermenter in my water bath, then adding the ice bricks the next day then wacking it in the fridge.

So over 3 days ~16, then 10-12 then dropping to 2.

 

[Fourstar]

A diacetyl rest isn't always necessary (especially if there's no diacetyl!) but it can also help finishing off fermentation. 1-2 days is enough for a diacetyl rest though.

A rest post fermentation doesn't clean up only diacetyl.There are other precursors you want to clean up, Acetaldehyde is the main one other than diacetyl, not to mention ensuring you hit final gravity without a stuck gravity and lower attenuation.

If you are planning on racking beforea diacetyl rest. Avoid doing a crash chill beforehand. you want as much yeast in suspension as you can. if it where me i'd ferment out with a temp raise for the last few points (it wont harm your beer in any way so why not?) The worst than can happen is your fermentation finishes cleanly and you have a shaper lager profile in your beer. Fresh on the nose with no hot alc/green apple aromas, or overpowering phenolics and esters.

Finishing that i;d crash chill for as long as you can handle in your primary fermenter (2-3days for lagers for me or yeast with low Flocculation, high floc i go for 24 hours.) Rack to the keg, force carb and lager away.

Cheers!

 

[bullsneck]

Fourstar, you're saying that lagering should be done post-carb?

I've always assumed that lagering happened pre-carbonation. Well you know what happens when you assume...

 

[Fourstar]

Fourstar, you're saying that lagering should be done post-carb?

I've always assumed that lagering happened pre-carbonation. Well you know what happens when you assume...

Post/pre, i cannot forsee any issues. i always do it post carbonation. maybe someone else cn shed some light on any issues.

 

[Brewman_]

Just a further question.
I have made plenty of lagers before, but as mentioned before in this thread they sometimes develop a sweet aroma / taste. I have not ever dobe a diacetyl rest before.

So doing first diacetly rest now. I have increased the temp from 10 to 17 Deg.C over the last 3 days. Prior to tincresing temps the gravity was 1011. I am expecting it to finish at 1008.
What I noticed this moring when I opened the feremnetation fridge was that same aroma I get sometimes in the keg, sweet smell, almost like fresh pears?? When it was fermenting at 10 Deg.C teh aroma was more egg - like.

I am a little worried that I may have imparted these aromas into the beer permanently? Or will the rest at these higher temperatures clean this up? Is this normal? It is definitely the same aroma that the kegged beer takes on after a week or two in the serving fridge. Should I continue to hold the fermenter at 17 to 18 until these aromas clear?

Any advice would be great.

Fear_n_Loath.

 

[manticle]

Sulphur is regulalry emitted by lager yeasts. I believe they are usually cleaned up by extensive lagering so I don't think the higher temps will help that. It does dissipate though.

 

[matti]

I may be wrong but I though diacetyl will not go away unless the fermentation going fairly strong still.
I.e 3/4 through the fermentation.
The C02 drive sit out. A diacetyl rest 3 to 4 points from final gravity will not have enough oomph left to do the job IMHO.
Usually the beer will ferment out during diacetyl rest.

When you rack to secondary I though you still needed a fair bit of yeast left in suspension.
If there is only the slightest hint of diacetyl the yeast left in secondary may absorb it but if you leave the racking too late the yeast will be left in the primary.

The best bet is to pitch 2 sachet or 2L of starter to a standard batch.
Then the diacetyl rest can be brief and still done in primary fermenter.

My 2c but there are more way then my way......

 

[Brewman_]

Sulphur is regulalry emitted by lager yeasts. I believe they are usually cleaned up by extensive lagering so I don't think the higher temps will help that. It does dissipate though.

Hi Manticle,
I was not too worried about the sulphury aroma as I have had that before and it dissapates in lagering. More worried about the sweet / pear smell?

Bye the way the yeast I used was Wyeast Urquell 2001.


Maybe I have left the rest a little late.

Fear_n_Loath

 

[buttersd70]

Is the smell actually in the beer itself? or is it what's come out of the beer and into the enclosed space of the fermenting fridge? Take a small sample, move away from the fridge, smell and taste....

Similar q the other day with strong diacetyl odour for an ale. Sure enough, the beer was free of it, it was just the fridge that reeked.

 

[///]

Lager fermentation is pretty simple. Allow it to run at the desired temp, put to VDK rest, crash cool, then remove from the excess yeast.

You can change the program and let it rise to 20c when the beer is 4-8 points off the target greavit. This will help in VDK reduction, or you may leave it longer at cooler temps, say 4 days.

A rest post ferment does clean up VDK - thats what the rest period is for ... yeast have a high affinity for VDK and will mop as much as it can. But, if you have an excess created from factors like a) under pitching B) over oxygenation and c) both a and b together, there can be excess and too much for the yeast to absorb. This can be rectified by adding in more yeast.

In all the HB beers i've had and judged, i've never had significant VDK in a HB Beer. I have had plenty in commercial beer, particarly beers run thru flash and tunnel pasturisers. One mate commented that VDK 'was the only flavour' in a beer that his brewery made ....

Scotty

 

[raven19]

Fermentation will drive out a lot of those bad unwanted flavours, better smelling them now, than drinking them later.

I reckon it will taste great once carbed up.

Keep us posted on progress!