Diacetyl

[BigNastyBrew]

I've been brewing all lagers since early December. I brewed several lagers last Summer (high electric bills). I practice the modified Narziss method that JZand Palmer advocate and it has worked flawlessly.

My Vienna lager has Diacetyl and I'm concerned about it and having a hard time troubleshooting.

Malt bill:
57% Munich
33% Vienna
8% Carahell
2% Carafa Special II

Pitched a nice healthy yeast starter (WLP830) based on Mr. Malty's calculator. Had normal lag of about 15 hours. Pitched at 45° and let it rise to 50°and let it ferment out there.

Funny thing.... I'm very sensitive to diacetyl flavor and I detected absolutely none in the fermentor when I was transferring to the keg. Pour my first pint of it last night and sure enough, there it is. Meanwhile, three other lagers done in the same time frame using similar methods show no diacetyl. Even my Helles came out very clean.

Any ideas for troubleshooting based on the info given?

[LocalBrewer]

The only thing that I can see is that your not doing a diacetyl rest. My steps are pretty much the same except I bump up the temp to about 58 when fermentation is about 80% done for a diacetyl rest and let that sit for about a day and then get the temp back down to about 48. I have had no issues with diacetyl in my finished beers. I have only brewed 3 lagers an EisBock using WLP830 and a Dortmunder twice using WLP833. I hope this is some help, good luck.

Cheers

[BigNastyBrew]

Thanks for the response.

I stopped doing diacetyl rests when I went to the Narziss method of pitching cold. For 8 lagers between last Summer and now, I've had no diacetyl issues. This is the only one.

I guess I'll have to just start being more aware of it even though I'm using the cold pitching method.

[Otterbrew]

I agree with the Diacetyl rest step, or you need to be really patient. I have been doing a lot of lagers recently also, and if I need to get them done quickly, I will go with the Diacetyl rest, then crash.
Good luck,
-Greg

[crupp]

I follow the same process (pitch cold, let it rise to 50, and hold it there). I stopped doing a diacetyl rest based upon JZ's suggestion. However, ever since I stopped doing a diacetyl rest, I have had diacetyl (in varying levels) in all of my lagers. I am back to doing the rest and haven't had any problems.

[BigNastyBrew]

Glad to see I'm not the only one.

I'll start doing diacetyl rests again.

[Sent From My iPhone]

[philbrasil]

I am having a similar problem. After fermentation I taste my lagers and they are a bit green, but no diacetyl. Then after going to keg, and crash cooling it, about a month later I can taste diacetyl. Don´t really know what the problem is. I don´t think is a bacterial infection since all my other ales don´t have any signs of infection.

Is it possible to raise the temp. back again to 60 or so to try and get rid of this diacetyl? I say that because I think I still have some yeast in solution. I am really disappointed cause the beer tastes great without diacetyl, very clean and all. I fermented at 48-50.