Banana in my pilsner!

[simonp]

Having just bottled my pislner style lager I tried some of the remainder to see how it was. It tastes just fine except there is some bloody banana in there :evil:

How can this have happened?

It was an extract brew that was fermented using Saflager S-23, fermented at 12C fro about 14 days. Then 72 hours diacetyl reast (as there was a slight banana taste after fermentation). Then lagered at 7C for approx 2 weeks in a secondary fermenter (as I read that longer doesn't help with S-23).

I am rather dissapointed, given the method, that there is bannana in there. The only thing is that for the first 24 hours of fermentation I did not have the fridge controller so it was left on the garage, the temp should onlt have got up to around 17C though as it was a cool day.

I was hoping that the diacetyl rest would have claered up buttery/banana flavours, but seemingly not.
Is this lileky to improve over time or during the bottle carbonation?

 

[leondz]

Banana is an ester flavour, and esters come from stressed yeast. An uneducated guess would be that pitching insufficient yeast, sleepy yeast, or pitching yeast too cold would stress it in this case; once its established, I'd suppose that lagering should be fine (it sounds like you've done more research on it than I!)

Removal - no idea, sadly.

 

[simonp]

As for yeast, I used 1 packet, but it was only an 11 litre batch so that should have been fine. It was pitched with the wort at 20C and held there until the first signs of fermentation. Fermentation was complete in about 12 days, which I understand is about right for S-23 at 12C.

I have read that S-23 does produce some estry flavours though (even mentions it in the yeast spec), so perhaps this is just the manifestation of that.
I guess the proof of the pudding will be after a few weeks as it is stil pretty young for a lager.

 

[Dunfie]

Not sure what your problem is Simon. I would usually associate banana flavours with a fairly high fermentation temperature but it sounds like that it not the problem. I intentionally do it with my wheat beers to encourage the banana and clove esters.

I once made a beer that I felt was infected but there were also banana flavours through it. I would pour a pint and take a sip and think "Not right but drinkable" but as I was getting to bottom it was too much adn I couldn't finish it. Mind you this was after conditioning and from my old King Keg so it probably was infected.

 

[simonp]

I would usually associate banana flavours with a fairly high fermentation temperature but it sounds like that it not the problem. I intentionally do it with my wheat beers to encourage the banana and clove esters.

Yes I also did this with my recent wheat beer, and the banana there is most welcome :)

As I said, the first day of fermentation was higher than ideal, I know the ambient outside was forcast as being around 17C. Whether this was the case I don't know, and the temperature in my garage ending up warmer then this is certainly a possibility. Perhaps this is the source.

The sample (uncarbonated) certianly wasn't undrinkable, after that initial hint of bannana on the first sip it fades on further sips and you get the malt and hops come through well. The dry hopping certainly added a nice aroma. I guess until it is carbonated I won't get a real idea of how it will really be.