Please help with diacetyl problem (or tell me I don't have one!)

[hokieengr]

Can anyone tell me what I am doing wrong??

I recently started to brew lagers. My third one is lagering as I type this. All three have tasted very buttery after primary fermentation and I can't figure out why. Perhaps this is normal? Here's what I did:

1. Transfer wort from kettle to carboy using pump w/ aeration tip (assuming well aerated).
2. Cool wort to 44 degrees.
3. Pitch a decanted started (first two lagers were 2L, second was 4L).
4. Raise the ferm temp from 44 to 50 over a few days.
5. When the fermentation is about 2/3 to final gravity, raise to 60 degrees.
6. Try to wait until no butter however after two weeks I gave up and started reducing at about 3 degrees per day.
7. Keg and wait.

Now, the first two were forgotten as I was sure they were goners. I decided to test them after about 3 months just before I dumped the keg and discovered the diacetyl was all but gone. This was encouraging.

So, back to my original question: do the rest of you produce lagers that when they come out of the primary after 2-4 weeks exhibit no buttery flavors at all? If so, what are you doing different than me??

FYI, the first two batches were 2208 and the second was 2206.

THANK YOU!

 

[samc]

Did you do a step up starter to insure enough yeast for the cold pitch? A lack of overwhelming yeast combined with the aeration tip method might have given you a sluggish ferment over what BCS is preaching. I assume that is what you used as a guide from your stats.

But you did find out that long term Lager cures a lot of ills. So planning far in advance for long term, think Oktoberfest 2012 !

 

[hokieengr]

Yes, you are correct. The fermentation schedule is out of BCS. I read after I made the first two batches about the need to pitch a lot more yeast when pitching cold which is why I pitched 4L the next time. Furthermore, I even used two packets to make that 4L starter to see if that was the problem but no joy.

 

[samc]

Try this calculator for figuring step up starters. See if you made enough cells. I'm doing one now with one tube of yeast, 1.5L starter which I will decant and pitch to a 3L starter.

 

[Darwin18]

How were you controlling your fermentation temperatures? Generally, if you pitch at fermentation temps and with the correct pitching rate, you shouldn't have perceptible diacetyl.

 

[MrManifesto]

easy diacetyl test...

you need two class, a cold water bath and a hot water bath, a thermo and some aluminum foil. pour some wort (fermented but before bottling) into the glasses and put one into the hot water and one into cold, covering with foil. let sit for 20min. then take the hot sample and put it into the cold water, you want to make them the same temp. take off the foil and smell. the cold is your control, if the hot sample smells buttery, you need more time on the yeast.

 

[hokieengr]

@Darwin
I control my temps with a digitally controlled deep freezer. The probe is taped directly to the carboy. I have never noticed any issues with it not nailing temps.

@Manifesto
I am aware of this test procedure but have questioned it--or at least its interpretation by the homebrew community. First, why would we bother with the cold sample? If just the hot sample is clear of a buttery taste, then why do we care about the cold sample? Secondly, if the cold sample tastes buttery like mine does, why then continue and prove that the hot sample also exhibits diacteyl? I've wondered this for a little while actually.

Thanks!

 

[Reno_eNVy]

@Manifesto
I am aware of this test procedure but have questioned it--or at least its interpretation by the homebrew community. First, why would we bother with the cold sample? If just the hot sample is clear of a buttery taste, then why do we care about the cold sample? Secondly, if the cold sample tastes buttery like mine does, why then continue and prove that the hot sample also exhibits diacteyl? I've wondered this for a little while actually.

1) Not a science person, are you? A control is always needed when testing.

2) Maybe you're just tasting something a little different. I'm not saying you're wrong but a lot of this stuff is based on perception. Give the test a shot, you may surprise yourself with the results.


I think it has to do with the starter size. I've made a lager with an insufficient starter and got a ton of diacetyl and sulfur. I'd say if the test comes back positive for diacetyl you could always try warming it back up to 60*F and pitch some neutral ale yeast (Notty, US-05) in hopes they will clean up the diacetyl.