Author Topic: Bananas and Stale Beer?  (Read 188 times)

Offline jaclynspradling

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Bananas and Stale Beer?
« on: May 03, 2019, 08:33:55 AM »
Ok, so this has been bugging me for a while. Many times, with stale but not totally oxidized beer (it doesn't taste like cardboard or sherry yet) I get a definite banana flavor.

I find it's more common in pale lagers, but I do get the same thing from some ales, SNPA being a definite one.

Anyone else ever get this? Or am I just mis-identifying another flavor? We aren't talking Weißbier levels of banana, just kinda enough to know it's there.

Offline RC

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Re: Bananas and Stale Beer?
« Reply #1 on: May 04, 2019, 07:54:58 PM »
Banana flavors come from any of several different esters produced by yeast, isoamyl acetate being the main one (as well as the main cause of banana in German hefewiezen). This ester is produced by many yeast strains, not just hefeweizen strains, but usually at levels that are not tastable. I've never tasted banana outside of the hefeweizen style, and certainly never in SNPA.

What I've definitely tasted in my and others' IPAs is that when they get older, the fruity hop character transforms into a pineapple-like flavor. Tastes like old Dole pineapple juice in those little cans. Perhaps this is what you're tasting?

Everyone's taste buds are different, it could be that you taste banana when the rest of us would taste, say, mango or pineapple.

Offline ethinson

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Re: Bananas and Stale Beer?
« Reply #2 on: May 04, 2019, 11:32:13 PM »
As hop flavor/aroma fades in aged beer you're going to pick up flavors that you didn't perceive before.

Something it could be, as crystal malts age (which I believe SNPA would have as an "old school" pale ale) they tend to take on some aromas like caramel, brown sugar, etc.  I can certainly see how that might be perceived as "fruity" or "banana".. again, like RC said, everyone's palette is different, if it's banana to you it's banana. But considering we're talking about stale beer I'm going to assume it's a product of aging and oxidation rather than yeast esters.

In theory (because I'm not going to say 100% ever) you shouldn't get isoamyl in lagers since they ferment cold. Esters are more expressed in warmer fermentations, so again, it could be a function of aging/oxidation that's doing funky things to the malts.
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Offline Robert

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Re: Bananas and Stale Beer?
« Reply #3 on: May 05, 2019, 12:24:37 AM »
Some Type Saaz lager yeasts, including the one used by the Žateč (Saaz) brewery, do give considerable amounts of esters, including distinct banana.   I've tasted it.  All lager yeasts of course produce esters, and they are an integral part of the character of the yeast and the beer.  Just more restrained than in ales, as noted in part because of fermentation temperature.   I would agree that they may be more noticeable as the fresh hop and malt notes fade.  As esters are the product of an alcohol and a fatty acid, I wonder if there is some purely chemical (non fermentive) mechanism by which they might be produced in staling beer containing some higher alcohols and oxidized lipids?
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