Try to be fancy then... Banana Bomb

[Kaze]

Last year I brewed about 100 gallons of beer, and was feeling confident so I decided to stretch my wings and try some new methods. Alas, like Icarus I flew too close to the sun.

I brewed a simple Classic American Pils with some 6row, flaked corn, and Vienna. Single vessel BIAB, 10 gallon batch. OG was 1.060 (higher than I was shooting for). I split the batch into two fermenters:

"Fancy" fermenter - Yeast WLP029. Stainless steel 7 gal sanke with a thermowell / pressure setup. This goes into a mini fridge that is controlled by an inkbird set to 64*f. I let this ferment without pressure for a few days until it slowed down, then closed it up and set the spunding valve to 25psi, hoping it would naturally carbonate. First time using this method.



"Other" fermenter - Yeast US05. Better bottle, ice chest, swamp cooler method. Stayed in the mid 60s.

For the WLP029, I used the Brewers Friend yeast pitch calculator, which recommended a 1L starter. I wanted to save the yeast, so I made a 2L starter with some DME on the stir plate the day before, and pitched 1L of it the next day. This is my first time making a starter.

For the US05 I just dumped the packet in the fermenter.


Fast forward two week, time to keg. The pressurized fermenter ended up losing most of its pressure due to a leaky gasket. This is my first time using it so oh well, better luck next time. Pull a sample from it and... BANANA!?!?! .

Pull a sample from the "I don't really care about you" better bottle and it tastes exactly like I would expect it to. No banana.

So, why banana from the WLP029? Was it fermenting under too much pressure? I read a blog post saying the pressure was supposed to reduce esters. Did I somehow under pitch the yeast?

TLDR: First time using pressurized fermenter. First time making a starter. Big banana flavor and aroma with WLP029. Other fermenter is treated with a lot less care and some US05, tastes fine.


I guess the moral of the story is... Don't try too hard

 

[Smellyglove]

My two cents on it:

You fermented without pressure the first days, that's when most esters are formed.
17C is about 3C to high I'd say.
Maybe underpitch?
Maybe to much glucose in the wort? Mashed low?
Higher OG will give you more esters.

05 is a strain IMO which is "pretty" clean unless you go low. 029 has a potential to give you esters.

 

[Kaze]

Mashed at 146*F / 63C for 60 min. Dropped to 142*F / 61C by the end. I think I probably underpitched somehow... but I'm surprised that it made so much banana esters.

 

[Smellyglove]

Mashed at 146*F / 63C for 60 min. Dropped to 142*F / 61C by the end. I think I probably underpitched somehow... but I'm surprised that it made so much banana esters.

Then I'd say you primed your wort for some banana-action, together with OG, the pitch and fermentation. Not written in stone as a definitive answer, but that's my thought.

 

[Azura]

White Labs says

WLP029 shouldn't be fermented at any less than 62°F. People may experience problems under 16°C, so we recommend that temperature, but many do ferment cooler. You just have to be more careful and keep an eye on the fermentation. With WLP029, you don’t need to ferment that cool anyway to get the clean flavors, you can cool it during fermentation if you like, but I wouldn’t do so the first time so you can see what you think.

So they claim it's a clean yeast higher than 62F. Conventional wisdom says higher temperatures create more esters. This is often true, but I don't think it's universally true for all strains. IME, some yeasts make banana when they are fermented cool, but they make less banana fermented warmer. Maybe wlp029 is one of those yeasts? Next time try 68F.