Interesting problem - Hot alcohols

So, I brewed up an Altbier, oh I dunno, a while ago. I am at work and don't have my sheets in front of me. Anyway, I pitched said altbier onto a cake of Wyeast German Ale 1007 that I had used to ferment a Kolsch previously.

Well, my keezer has been pretty full for while, but I finally got my keg of altbier into the keezer last Friday. I tried a sample last night just to see how the carbonation was going; and obviously I was excited to see what it tasted like. Well, to my dismay, although the beer did taste mighty fine, it has a definitely hot alcohol aftertaste. At first I thought maybe it was just the first pull and maybe there was some starsan left in my lines or something. So I tried another sample, and the hot alcohol was still there.

Now, this was surprising to me because I know fermenting on the hotside will cause hot alcohol flavors and I know that certain strands of yeast sometimes produce hot alcohol flavors, but neither should have been the case. I have used 1007 a number of times and it is a very clean yeast IMO, and I brewed this particular beer over the winter on the low side for the strain; around 58 degrees.

So, this morning I went to the old standby and read something that I guess I overlooked previously:

Fusel alcohols can be produced by excessive amounts of yeast...

Click to expand...

So, I guess that by pitching on the cake of the Kolsch, I actually overpitched my beer and created fusel alcohols.

I am actually not concerned about it. It is a pretty minor flaw and I would imagine that it would condition out over the next couple of weeks, but I just didn't know that was a problem, and had I of known, I probably would have thought it to be just about impossible on the homebrew side.

So there ya have it, pitching on a cake of yeast can lead to overpitching and off flavors associated with it. I am going to have to be more careful next time.

Good to know. My desire to be continuously brewing has recently been reinvigorated, and I was considering doing this very thing, so I could save on yeast costs...

Thanks for the note!

What were the OG's of the two brews?

Dont have the sheets in front of me, but neither were excessive and both were similar. Both in the 1.045-1.050 range.

I have gotten into the habit of washing the yeast, or if I reuse the cake it is only once, and usually after I have removed some of it.
Thanks for providing an example of why it's good to do.

I do wash my yeast, but if I am going to use the same yeast back to back, I will just use the cake. I have done this a number of times with no problems. However, I am convinced that overpitching due to the cake was the problem with this beer. From now on I will take a cup or so of the cake out before racking on top of it.