WLP007 Banana Aroma and Fermentation Question

I just kegged my second batch of the CYBI Arrogant Bastard Clone (90% 2-Row, 10% Special B). The first batch turned out really well and scored a 38 in competition. No problems with that batch. The second batch has been in the keg for a week. I pulled a bit off last night just to see how it's carbing up and when I tatsed it I got lots of banana aroma and flavor.

I did some checking and it looks like the fruity estery flavors come from warmer fermentation temperatures or under pitching yeast. Heres where I have questions.

I have a controlled fermentation chamber. I made a starter going by mrmalty.com. I pitched my yeast at about 65 degrees and over the course of a week and a half slowly ramped the temperature up to 70, where I left it for 4 weeks in the primary. Crash cooled to 38 for 4 days, racked to keg where it's been under 11 PSI at 38 degrees.

Like I said in the beginning, the first batch turned out great. Second batch, same process and bananas. The only difference between the two batches was that the first batch had massive fermentation and blow off where the second seemed very quiet. I never needed the blow of tube at all. I got about 78-80% attenuation from both batches so my gravity numbers were fine.

Has anyone had any experience like this or can any of you guys help me figure out what went wrong. Is this something that will mellow out with time?

Any ideas??

Tell us more about your pitch rate/starter size/yeast care, etc.

I did a 2.5 liter starter for a SG of 1.072. This was supposed to give me ~280B cells. I used a gallon jug with intermittent shaking, for about 36 hours, then refridgerated for a day, then took it out about 3-4 hours before I pitched it. The yeast was bought at a fairly new HBS and they actually had ordered this WLP007 at my request so it had to be fairly fresh. I didn't check the date. It stayed in my refridgerator until the night I made the starter (about a week).

Then I'm kinda stumped, but I wouldn't get too worried yet. It sounds from your description that you have some more time to go, plus the conditioning and packaging phase.

give er time

I had similar situation with a lager-it was a fresh banana smell-I let it sit for a while in the primary and secondary (it was still there) then I kegged and after two weeks the smell was unnoticable. Not sure why because generally this ester doesnt go away completely-im starting to wonder if it isnt a charateristic of certain malts that need to meld together-and maybe not an ester so to speak and -------it will be fine!!

reinstone, thanks for the advice! I still have 2-3 weeks before I would really start on it anyway so maybe it will subside. I just want to try and figure out what happened so it won't happen again. I'll post after a couple of weeks and hopefully I'll report back that it did go away!

A furious fermentation (even without kraussen or blowing off can raise the temperature of the fermenting beer by 6 degrees or more on a bigger beer. I'm guessing the 65 pitch temp was of the wort, but were the other temps mentioned the dialed in chamber temps or were they the liquid temp?

WLP007 has been known to finish in days, so if it ran up overnight and finished quickly, you may not have seen it. and you chamber may not have registered the change quickly enough to cool it down.

Just spitballing. I'd really be surprised with a cool pitch to have that happen to you.