Having two samples makes it easier to taste the difference. One was heated to cause the diacetyl to form. The other was not. Precursor is not tasteable for us humans. If they don’t taste the same after hearing and cooling one of the samples, there is a problem.
Has anyone trained dog to detect diacetyl or better yet precursor? Seems like a worthy endeavor. You could make a career traveling from brewery to brewery helping save beer one batch at a time. I’m thinking the dog trainer would have sample privileges also of course.
My threshold for detecting diacetyl is quite low, meaning it’s very easy to pick up, even in minute amounts. I think this is true of most educated beer drinkers.
Our beers have had a complete lack of this issue…maybe we are just lucky? I personally would dump the beer if this was detected. I do not like it. Not one bit.
If a higher temp near the end of fermentation (and after fermentation) has anything to do with it, location could be key. A beer sitting on the floor in Texas (my son tells me that Texas doesn’t have many basements) compared to a beer sitting on a concrete basement floor in Chicago in the winter could be as far as you need to look. As mentioned… all spring and summer with 940 and Bayern… no diacetyl. Now this fall with cooler temps and WLP001 and two beers with some diacetyl. I’m not trying to make it easier to explain but it could be that simple.
It’s definitely easier to warm up beer in the South.
I think having plenty of yeast is also important. I can’t recall having had diacetyl issues since moving to 2.5 gallon batches. I over pitch almost all the time now since I always pitch a whole pack of yeast for half a batch.
I also get all my beers into the mid 60’s in primary for a few days.
On the pitch rate, I remember hearing some things about pitching the proper amount and I think we have batted it around here before. Some people say it’s hard to overpitch at the homebrewer level but there was talk about the various phases that yeast goes through and how those phases create flavors that beer drinkers find pleasing. If you pitch more yeast than you need then the yeast may not go through that phase and those flavors will not be produced. That might be a fine point but I have been keeping it in mind and trying to dial in the proper amount of yeast to pitch.
Keep in mind it’s not the temp itself, it’s the effects of the temp. Meaning anything you can do to keep the yeast active will reduce d. Thats why krausening is so effective.
To add to Denny’s point, we all have different sensitivities for all of our senses. About 20% of the population is blind to Diacetyl, that is genetics, similar to about the same amount that say Cilantro tastes like soap. We all have different compounds we are sensitive to, or not.
Whoa. You can’t smell asparagus pee? That’s like a superpower. I eat asparagus and 30 minutes later I go pee and wonder if I’m on death’s door because of the fumes… Oh. It’s just the asparagus. Thank Jeebus.
Anyway… I understand that part. We’re all playing with different variables. I don’t want to do too much at once so for now I will assume that these beers could use some warmup prior to being sent to the keg. I will start with that and if I don’t see an improvement I will move down the list. Thanks for the help and for the link. Much appreciated.
Update: I have a pale ale in the fermenter that was brewed on 12/6. It was taken out of the fridge and given a mild swirl and that was probably on the 12th or so. Every day I have given it a gentle swirl to make sure the yeast is in suspension and hopefully slay the diacetyl. Last night around 10pm I grabbed a small sample of the beer through the spigot. No diacetyl detected. None. Ordinarily I would take the fermenter out of the fridge, swirl it once and then just leave it. That may be fine when the weather is warmer but when it’s cooler this is probably mandatory. I have a lager going now too and I will do the same and also taste it before sending it to the keg. Cheers Beerheads.
I’ve always wondered this as well. If the yeast flocced out already, is giving it a swirl really going to do much other that make you wait for the flocced particles to settle out again?
I see what you’re saying. On one of the batches that are on tap now, there is slight diacetyl. That batch was probably in the fridge for 5-6 days and then taken out, swirled and placed on a plank of wood (to keep it off the colder floor) between two fridges where it’s warmer. The fermenter was not swirled again after that initial time. This batch has been swirled now 4-5 times and I plan to send it to the keg on Friday. The swirling is also going to allow a bit of blowoff… do you feel like that has any impact on it? I will taste another sample before I transfer it just to verify the presence of diacetyl but when I sampled it earlier this week… no diacetyl.
I would absolutely agree but in the end… if this particular beer (handled slightly differently) does not have diacetyl then I wouldn’t necessarily lose sleep over the WHY part. I suppose that I don’t know that this beer EVER had noticeable diacetyl so there is that part of it. As the temps continue to be cool, I will monitor things more closely and sample the beer prior to transferring it to the keg. If those steps keep my beers diacetyl-free, I will dance, cheer and raise my fists in victory!
