I'm still relatively new to lagers. I generally make a huge damn starter and don't care if I overpitch. I just try to lock the temp in at about 55F and I let the yeast run its course until I think I should run a D-rest. If I get airlock activity, it's roughly +- 24 hours of airlock activity stopping. If I don't get airlock activity, I just wait about 5-7 days and bump the temp up to about ambient 68F. The last lager I made stank of green apple, even after cold conditioning for 4-5 months. The beer was about 7 months old when the keg kicked. The last hybrid beer I made (Cali Common with the Wyeast Cali hybrid yeast) is currently on tap and starting to mellow out. It's showing a lot of green apple flavors. It's currently 4 or 4 1/2 months old. It's not a terrible taste to the beer, but I want it gone next time I do a clean lager. Age comes up over and over in the Google searches I do on acetaldehyde. Am I just rushing these lagers? Any other tips are most welcome.
Do you rack all your beers to secondary? If so, try keeping in primary the entire time and skipping the secondary. Works wonders for lots of off-flavors, acetaldehyde included. Fortunately, acetaldehyde as a chemical compound boils at about 70 F. So, if your D rest was lifted up above that mark, maybe 72 F, for a period of 3-4 days, this might resolve the problem for you. And for anything already in the kegs, you could try warming it up and purging over a period of several days, and see if that helps. Good luck.
I don't think I'd expect cold conditioning to do much for acetaldehyde, at least not as efficiently as at higher temps. I think the time to clean that up is at the end of primary (or fermentation-ish temperature secondary if using one), and make sure it's gone before reducing the temps.
I do a D rest when my airlock gives me 1 bubble every 15-20 seconds. I take my fermenter to a room that is 65 degrees. I will leave it there for four days then back to my lager fermentation temperature. I let my lagers sit on the yeast for a total of three weeks. Never had an acetaldehyde issue. Good luck.
I am sorry I chimed in . I was thinking of diactyl. ( smack smack! ) However leaving your beer on the yeast cake for three weeks should take care of your problem. Take care.
Jim, your post is still germane. Reduction of acetaldehyde and diacetyl occurs at the end of primary fermentation. Conducting a diacetyl rest should benefit the 'clean up' of both acetaldehyde and diacetyl. Cheers!
I go from primary into keg. I think I rush primary a little more with lagers. and tend to not let them sit as long as ales in prmary. I think I rush primary with lagers. I should be lazy, (like I usually am) and let it primary for 3-4 weeks? Good practice is good practice. ^^^ from above, I wonder if just running a D rest at 73 of 74F wouldn't be an incredible idea.
P.S. It seems like the Germans were best at lagers. Discredit me or them if you may. How the hell did the run a D rest in a cave notorious for creating a colder fermented beer?
I don't know if I'd put a specific timeframe on it, but yeah, I'd say until any diacetyl and/or acetaldehyde are cleaned up. They didn't do high temperature D rests, but IIRC they started cold storage before fermentation was actually done, lowering the temperature slowly to keep the yeast active. Thus the yeast were able to clean up after themselves at lagering temps. I think this is the link to Kai's page where he discusses that, if I'm not misremembering the whole thing... http://braukaiser.com/wiki/index.php?title=Fermenting_Lagers
You might be interested in watching the Beersmith podcast with Dr. Charlie Bamforth on the topic of diacetyl (see below). @pweis909 The broader question is: do commercial breweries conduct diacetyl rests for lagers? The answer is no. It could be suggested that we homebrewers have an ‘advantage’ over commercial breweries since we can easily conduct a diacetyl rest for lagers; simply take the beer from the fermentation chamber and let it come up to room temperature. I have brewed a large number of batches of lager (over 75 batches) and I have never conducted a diacetyl rest for any of those batches and I have never had an issue with diacetyl (or acetaldehyde) in any of those batches. So, conducting a diacetyl rest is not absolutely required but YMMV. Cheers! P.S And I am very sensitive to diacetyl so I would smell/taste it in my lagers if it was there.
Maybe some don't. But I can guarantee that some do. I've done it myself in a commercial brewery. What are you basing your answer to your broader question on? IIRC, White Labs talks about how diacetyl rests work in their commercial brewing home brewing pages. I suspect it's not rare.
Perhaps I should have used an adjective of “larger”, as in larger lager commercial breweries like AB, Miller-Coors, etc. It would be costly from an energy perspective for those breweries to raise the temperature of their extremely large fermenters to the high 60’s for a few days of rest. Cheers!
