Green apple & Repitched Yeast

I brewed a Scottish 80 and I'm getting a green apple taste after 12 days in the primary. I’m pretty sure it is acetaldehyde from over pitching yeast.

I made a 1 L Y1056 starter appropriate for a 5.5 gallon batch, gravity of 1.050, and using a stir plate. While I hit my OG I only put about 4.4 gallons in the carboy (thus a 25% over-pitch). When I pitched into wort I oxygenated for 50 seconds and fermented at 65 degrees. I crash chilled it after 12 days to make it easier to siphon the beer off the yeast into the keg.

My hope is that it will clean itself up with time. It is in a keg now at room temp (about 77*) and I have not filtered it so there is still some yeast. If it does not clean up on its own I was planning to add a little healthy yeast back in to finish absorbing the acetaldehyde.

Assuming this was simply a green beer issue and not being able to get to the LHBS for a couple of days, I repitched the yeast into a blonde (I know it is the wrong sequence SRM-wise). I would think that the active fermentation of the blonde would clean up any green able taste in the small amount of Scottish 80 that got pitched into the blonde with the yeast.

I am hoping that this is not an infection and that I ruined two batches.

What do you guys predict? Am I screwed or will I have two mellowed out beers in a few weeks?

Thanks,
Dan

I don't think you need to worry about infection, but if you overpitched it likely is acetaldehyde. Try rousing it up some, and make sure there's no pressure in that keg. If it won't go away on its own in a day or two and you want to try to get rid of it, pitch a small starter at high krausen of some healthy active yeast, and you may be able to get some of it cleaned up. If that doesn't work, you may be out of luck, acetaldehyde isn't something that settles out over time.

Now I'm confused?

I have reused yeast cakes in the past and never ever had a green apple taste or a problem, I would definitely consider a yeast cake over pitching, since I couldn't even start to count the number of cells in a yeast cake.

Cheers,
Frank

Homebrewcrazy said:

Now I'm confused?

I have reused yeast cakes in the past and never ever had a green apple taste or a problem, I would definitely consider a yeast cake over pitching, since I couldn't even start to count the number of cells in a yeast cake.

Cheers,
Frank

Click to expand...

I brewed two batches of beer. I think I overpitched the first one (made with a yeast starter). It has a green apple taste.

I used the yeast from that first batch (even with the green apple taste) to ferment the second. I didn't use the whole cake. I measured out what I need in a Nalgene bottle.

My question is if the second batch will be okay. I've guessing yes because it is going to go through a complete fermentation and I'll give it time to clean up.

Hopefully that clarifies. Any predictions? Thanks.
Dan

I thought I'd post the resolution of the question I asked above in case someone else searches and has the same confusion about "acetaldehyde."

It turns out that the "green apple" taste in the Scottish Ale was just "green beer" taste. With several weeks to mature in the keg the Scottish Ale is awesome. I should have known. While I over pitched a little, many people pitch on a full yeast cake with fine results.

Unfortunately, I didn't give my Blonde the same time to "lager" and dumped it under a mesquite tree when it had the same taste. The up side is that the tree is thriving, my Scottish ale rocks, and I learned something!

The thing to remember though is that if you are smelling or tasting this during fermentation not to worry. During fermentation all manner of stinky stuff is given off (ask lager brewers about rotten egg/sulphur smells, or Apfelwein makers about "rhino farts,") like we often say, fermentation is often ugly AND stinky and PERFECTLY NORMAL.

It's really only down the line, AFTER the beer has been fermented (and often after it has bottle conditioned even,) that you concern yourself with any flavor issues if they are still there.

I think too many new brewers focus to much on this stuff too early in the beer's journey. And they panic unnecessarily.

A lot of the stuff you smell/taste initially more than likely ends up disappearing either during a long primary/primary & secondary combo, Diacetyl rests and even during bottle conditioning.

If I find a flavor/smell, I usually wait til it's been in the bottle 6 weeks before I try to "diagnose" what went wrong, that way I am sure the beer has passed any window of greenness.

Fementation is often ugly, smelly and crappy tasting in the beginning and perfectly normal. The various conditioning phases, be it long primary, secondarying, D-rests, bottle conditioning, AND LAGERING, are all part of the process where the yeast, and co2 correct a lot of the normal production of the byproducts of fermentation.

Lagering is a prime example of this. Lager yeast are prone to the production of a lot of byproducts, the most familiar one is sulphur compounds (rhino farts) but in the dark cold of the lagering process, which is at the minimum of a month (I think many homebrewers don't lager long enough) the yeast slowly consumes all those compounds which results in extremely clean tasting beers if done skillfully.

Ales have their own version of this, but it's all the same.

If you are sampling your beer before you have passed a 'window of greeness" which my experience is about 3-6 weeks in the bottle, then you are more than likely just experiencing an "off flavor" due to the presence of those byproducts (that's what we mean when we say the beer is "green" it's still young and unconditioned.) but once the process is done, over 90% of the time the flavors/smells are gone.

Of the remaining 10%, half of those may still be salvageable through the long time storage that I mention in the Never dump your beer!!! Patience IS a virtue!!! Time heals all things, even beer:

And the remaining 50% of the last 10% are where these tables and lists come into play. To understand what you did wrong, so you can avoid it in the future.

Long story short....I betcha that smell/flavor will be long gone when the beer is carbed and conditioned.

I had a batch with acetaldehyde that did not age out, after pitching on a cake for two subsequent batches. Usually, it will age out as long as the beer has yeast still in it.