34/70 Pilsner and yeasty-funky smell/taste

[pvanessen]

Hey guys,

I am brewing mostly german beers (b/c of my heritage) and routinely do a 5 gal batch of Pilsner. I have done this one 6 times and have had consistent results in terms of OG, FG, taste and smell.

The last one came out funky. After secondary and lagering (2C, 3 months), it is somewhat cloudy and smells very yeasty. The taste is somewhere on the grassy-citrus side (used only Perle during the boil and no dry-hopping).
The beer looks clean, there are no bacteria colonies floating on the top or anything. And the smell/taste remains stable, even over weeks (batch is lagering for 4.5 months now).
I am not a big fan of Belgians, but that is the first association that my mind jumps to every time I pull a sample.

The yeast was 4th generation of 34/70 that I used in other Pilsener batches before. The only difference to previous brews was that I did not give the cake a 'vacation' in my fridge but washed it and pitched it the same day after harvesting it to the new batch.

My questions is around methods/options to try to diagnose what I am (probably) looking at - and possible ways to save the batch.
Is it likely to be an infection? Or did I contract some wild yeast? Or is the yeast stressed out?

I have another batch of Pilsener with 34/70 fermenting nicely. Should I pitch some of that and maybe 1-2l of 1.040 to feed it and have it clean up?

Any recommendation or tip is appreciated at this point.
I figured that I could try to save it - and dump if later in case it didn't work.

Best regards,
Phillip

 

[friarsmith]

The yeast may be stressed out or you might have an infection. If the worst aroma you perceive is "yeasty" then you might be ok. The grassy characteristic could stem from a combination of water chemistry and the Perle hops additions. I use 34/70 regularly and usually discard after the 3rd generation.

Try adding a 1L starter at 1.040 with some 34/70 yeast from your other fermenter. It's a minimal investment in time and money for a chance at saving the beer.

Not sure of your kegerator capacity, but it would be best to let the beer warm up to 8-10C and then pitch the starter. Give it two weeks or so at 8-10C and test.


I just fixed an American lager with some green apple flavors using the method above. It's clean as a whistle now. The new yeast ate up the acetaldehyde in a week at 50* F in a keg.