Diacetyl Smell

[bmantzey]

I've been working to make the lager process right so I can enjoy some good homebrewed lager.

I have 3 lagers almost done, a Sam Adams Noble Pils clone, a Bud Like, and a Fosters clone.

I racked the Bud Like into the secondary tonight and was disappointed to smell diacetyl. I also noticed it last week when I racked the Sam Adams to the secondary.

I did do a diacetyl rest, but I think I made some mistakes that created too much diacetyl. I was just hoping someone could verify that what I think I did wrong is what has caused the problems.

1) I pitched the starter into a wort that was about 70 degrees and then put it into the fridge to ferment at about 50°. It took about 3 days to get really going, and was definitely at 50° by then, but I think that since I pitched it warm, enough diacetyl was produced to create a problem.

2) I missed the diacetyl rest opportunity. I read that when the fermentation nears its end, that's when you should do a diacetyl rest. I also read something about doing it at any time as long as there's enough yeast in suspension. I also read that it could be done during the secondary phase. I concluded that it didn't really matter. Then I find out that you're supposed to do the diacetyl rest when there's no less than 5 gravity points left. I ended up doing the diacetyl rest when the krausen was almost all fallen in.

So, those are the mistakes I made during this brew, I think. Now I have them racked into their secondaries. The Sam Adams has a couple dry hops balls in the secondary, so I'll need to rack it again. I'm going to transfer it straight to the keg for lagering. I'll probably lager it at about 33° for a couple months.

To sum it up, it'll be in the secondaries for another week (<50°), and then I'll lager it for a couple months (33°).

So, now for the grand question. Is it possible that the diacetyl will go away in that time, and is there anything I can do to reduce the diacetyl at this point? Thanks in advance.

 

[COLObrewer]

. . . . 1) I pitched the starter into a wort that was about 70 degrees and then put it into the fridge to ferment at about 50°. It took about 3 days to get really going, and was definitely at 50° by then, but I think that since I pitched it warm, enough diacetyl was produced to create a problem. . . . . .

This could definately cause some diacetyl, how did it taste?

. . . . . . 2) I missed the diacetyl rest opportunity. I read that when the fermentation nears its end, that's when you should do a diacetyl rest. I also read something about doing it at any time as long as there's enough yeast in suspension. I also read that it could be done during the secondary phase. . . . . . I ended up doing the diacetyl rest when the krausen was almost all fallen in. . . . . .

If these are transferred to secondary, yes you may have missed your diacetyl rest opportunity. The reason you raise the temperature for the rest is to get the yeast to work overtime and clean up their ketones before they go dormant, if you rack to secondary, you are loosing some of that yeast. I typically do a diacetyl rest when the brew has reached 75% of terminal gravity, leave it in primary, raise the temperature appx. 10 degrees F until terminal gravity, leave it in primary and chill to lager temperature, I then secondary after the clarity is good, then I lager.

. . . . . So, now for the grand question. Is it possible that the diacetyl will go away in that time, and is there anything I can do to reduce the diacetyl at this point? Thanks in advance.

If there is a bunch of diacetyl, personally I would think it will not go away.

You can try raising the temperature 10 degrees F to see if there are enough yeasties not dormant, however if you have reached terminal gravity unfortunately there is nothing you can do to correct this (Outside of some wild experimentation with new wort and yeast which may or may not correct the problem).

It sounds like you have learned how to control this for future brews but if you need more help I'd suggest reading up on lager brewing, here is a link to Palmers section on lagers: http://www.howtobrew.com/section1/chapter10.html or you can purchase one of the books in his recomended reading section at the bottom of his book.