As it turns out, diacetyl is obvious. Who knew?

So a few weeks ago I took my first shot at a lager. Probably should have gone for something more forgiving, with some nice dark malts to mask any off-flavors...but what's the challenge in that? So I had my hand at a Bohemian pilzner. Simple extract recipe with pilsener extract, carapils for head retention, and saaz for bittering/flavoring/aroma.

After getting through the foul-egg smell, and the intense blowoff, I fixed my airlock and then left town for a few days, with fermentation set at 50˚F.

I came back to some beautifully crystal clear beer, so I racked it to secondary, saved the cake to re-pitch a bit of come bottling time, and siphoned a bit to a glass for a taste. "That's funny...what a strange flavor...nacho cheese? I wonder if that's...nah....better stick it in the fridge and come back to it"

So I gave the glass a half hour in the fridge to let a little bit of yeast settle out, even though I had a haunting suspicion that it wouldn't make a lick of difference. I took another swig, and was just about knocked over with buttered-popcorn-ness. Now personally, I've never been a fan of artificial butter flavor. At all. In fact, I remember being about 6 and puking my guts out when someone gave me a handful of "Buttered Popcorn" Jelly Belly's. Not a good thing on its own, not a good thing in a lager.

I'm leaving the carboy out of the fridge for a day at 60˚F to get rid of this nastiness, and I'll let you know how the flavor turns out. I just thought I'd put it out there that I thought I'd recognized this flavor in beer before, but goddamn, when it's there, you know it. In fact, it's noticeable enough that I almost want to run GC on a sample of this beer, just to see how much of this compound is creating such a flavor...but that's another story.

Here's to giving 2,3-butadione the finger.

FYI, yeast will clean up a lot of diacetyl flavors. Before racking to secondary, you should do a diacetyl rest. Let the ferment climb up to 68-70 degrees and hold it there for a couple of days. The yeast will turn the diacetyl into other compounds and the butter flavor will disappear. Then chill the primary back to 50, rack to secondary and start the lagering.

Lots of lager breweries will allow the fermerter temp rise near the end of fermentation just for this purpose. Keeping the beer on the big yeast cake aids in the process.

mrkristofo said:

Here's to giving 1,3-butadione the finger.

Click to expand...

LMAO!....... From your post, i'm sure you know more about diacetyl than i do. Over time, i just learned how to get it down below threshhold.......

If for some reason you did end up running your beer through a GC, I'd be interested in your sample prep and results. Just curious.

Funny... I've been homebrewing for a year now and I've learned a lot. Mostly what I've learned is that I have a lot more to learn. I mostly brew from kits, so I think I have it easy. I'm ready to start something new. diacetyl? Time to go read my book and figure out what this is...

hmmm... going to try a dortmunder in the next few weeks - my first lager. I'm interested to see what you learn.

I'll keep the "diacetyl rest" thing in mind.

jdoiv said:

FYI, yeast will clean up a lot of diacetyl flavors. Before racking to secondary, you should do a diacetyl rest. Let the ferment climb up to 68-70 degrees and hold it there for a couple of days. The yeast will turn the diacetyl into other compounds and the butter flavor will disappear. Then chill the primary back to 50, rack to secondary and start the lagering.

Lots of lager breweries will allow the fermerter temp rise near the end of fermentation just for this purpose. Keeping the beer on the big yeast cake aids in the process.

Click to expand...

Cheers. I'd been planning on a diacetyl rest, but a variety of sources said sometimes you'll need it, sometimes now. I suppose I should have tasted it before racking to secondary, but, c'est la vie. As far as climbing up to 68-70...65 is gonna have to do, since that's as warm as it is in my house. Maybe I'll let it sit at room temp for 3 days to compensate for the lack of yeast/cooler temps. 65 makes for fantastic ales, though!

I knew this stuff was bad news! No sooner had I posted that, then I picked up a copy of Chemical and Engineering news to find the following article: House Pushes 'Popcorn Lung' Bil. I know that link will probably only work for 2 of you, so here's a couple choice excerpts:

C&EN said:

Concern over diacetal exposure has risen dramatically since reports that workers mixing the compound in microwave popcorn plants have contracted serious obstructive lung disease. Major microwave popcorn makers have already pledged to stop using diacetyl in their products, but it continues to be used as butter flavoring in many other food products.

Click to expand...

Hot damn! House bill here.