hefe pressure fermentation "failure"

[odie]

I just tapped my latest hefe...no banana and lots of "grapefruitty" flavors. Or is that clove flavors? Tastes nothing like a hefe

I keg fermented around 10 psi in the mid 70s. Munich Classic that I've had success with for unpressurized ferments.

I gather I should have left the keg vented with a blow off tube for the first few days to let the yeast properly express itself?

Drinkable but NOT what I expected.

 

[Gusso]

Similar experience with me on a recent brew. I pressurized a Voss Kveik to 30psi. It totally scrubbed all of the flavor out. I somewhat revived it with a big dry hop in the keg. From now on, I'll stick to lagers under pressure.

 

[Spikybits]

pressure fermentation suppresses yeast from producing esters desirable in some styles - a cleaner fermentation. try using only 1-2 psi

 

[twd000]

pressure fermentation seems counter-productive to making a hefeweizen

https://braumagazin.de/article/brewing-bavarian-weissbier-all-you-ever-wanted-to-know/
" Open (non-pressurized) fermentation leads to the fermentation of significantly more esters as opposed to pressurized fermentation. "

I've heard at many of the traditional hefe breweries in Germany, not only do they not seal the fermentors, they often stir and rouse the yeast with a paddle every few hours to keep it aerated

 

[odie]

round 2....the Hefe poped last week and I left the keg cold. Brewed up another batch and dumped it in the same keg right on top of the yeast cake. I have a blow off tube rigged this time so hopefully I'll get some banana action.

 

[ebbelwoi]

That sounds like quite an overpitch. Overpitching can lead to an absence of banana.

I recommend checking out the link that @twd000 posted above.

 

[Toxxyc]

Yeah pitching too many yeast cells leads to the yeast not stressing enough to produce esters associated with banana. Seems like odie just can't grab a break!

 

[theGrantickle]

pressure fermentation suppresses yeast from producing esters desirable in some styles - a cleaner fermentation. try using only 1-2 psi

+1 to this. Most traditional German Heffe brewers use open fermentation, so there is no pressure build up at all in the tank.

 

[VikeMan]

Yeah pitching too many yeast cells leads to the yeast not stressing enough to produce esters associated with banana.

Overpitching does result in less banana, but I don't know where the notion of "stressed" hefe yeast producing Isoamyl Acetate (banana ester) originally came from. Isoamyl Acetate is a perfectly normal byproduct of cell growth, no different from other esters. The reason overpitching results in lower levels of banana is that there is less cell growth. The yeast sense that they don't need to propogate, so they (mostly) just eat.

 

[odie]

you guys are killing me I can't catch a break on my search for the elusive banana...

Well here is what happened. I brewed my hefe and chilled to 80-90ish...I say "ish" because my kettle thermometer read 80, IR thermometer reads 90 pointed at the wort surface. IR reads about 80 pointed at the kettle outside. So somewhere in that range is the true temps...perhaps even a little higher.

My keg is in the fridge, probably in the mid 30s? Yeast should be sleeping nicely. I open the keg and pour bout 2 gallons in. The stick thermometer strip on the keg jumps right up to 86+ but not quite 90. Quite the temperature shock. But the extra package I have of that yeast, Munich Classic, states rehydrate in warm water...temp range up to 92'. So I'm hopefully I didn't kill the yeast cake.

About 20 hours later, I'm observing no activity on the blowoff tube. Getting very concerned I shock killed the yeast. I open the keg and there is only a slight layer of "foam" that really looks more like aeration than krausen or anything else. Basically looks like it did when I dumped all the wort in, just residual air bubbles from aeration.

So I grab a Munich Classic yeast harvest out of my fridge, a few months old. Half pint mason jar with a good 1" think yeast cake. I decanted a bit, swirled it up and pitched half the cake, about 1/2" of yeast. Within 4 hours I have activity, followed by krausen blowing out the tube (expected) and 24 hours later it's down to a slow bubble like it's almost done.

So did the new pitch kick off nice an quick....or was my original dump on the yeast cake "just" starting to take off and I just didn't give it a chance? And thus I "super-charged" the fermentation with a second, unnecessary pitch?

 

[Spikybits]

I only set to 1-2 psi to keep positive pressure in the keg - are you sure your blow off tube is air tight? some yeast also take a few days to kick into gear, even on a yeast cake. not ideal but I have experienced lag time like that before.

You can also under pitch as suggested above to bring out esters. Also Munich classic, I wouldn't put money on it producing a lot of banana flavor. Maybe try something like WLP300 or a true Hef yeast.

If you are using Lalbrew Munich Classic, I do not see banana under the ester profile.

LALBREW MUNICH CLASSIC™ – WHEAT BEER YEAST
LalBrew Munich Classic™ is a Bavarian wheat beer strain that can easily express the spicy and estery aroma profile typical to German wheat beer styles. This strain is simple to use over a wide range of recipe variations and fermentation conditions, making it a great choice for a number of traditional styles of wheat beer. A true top cropping yeast, LalBrew Munich Classic™ yeast can be skimmed off the top of classic open fermentation vessels in the traditional manner. Styles brewed with LalBrew Munich Classic™ include but are not limited to Weizen/Weissbier, Dunkelweizen and Weizenbock.

 

[odie]

the lid was seeping a little as well...but the keg is not sealed since the last attempt under pressure did NOT result in a hefe tasting beer.

Using MC since that's what I've seen posted here as one of the better yeasts to replicate a classic german wheat like paulaner or fransikaner and the like...

I've used just the "Munich" and gotten just so-so....supposedly the "classic" is a bit different. But seems strange to offer what appears to be basically 2 almost the same yeasts.

I've used WB-06 before and gotten "banana" and missed the banana as well...

 

[ebbelwoi]

If you are using Lalbrew Munich Classic, I do not see banana under the ester profile.

https://www.lallemandbrewing.com/en/canada/product-details/munich-classic-wheat-beer-yeast/

 

[DuncB]

I " accidentally " fitted a new ball lock connector to my spunding valve and attached it to my only Hefe brewed so far, trouble was it was a NRV ball lock. When i returned from work after 5 days it was at 35 psi and bubbling furiously, venting all that pressure took a bit of time and I finished off with no pressure. Surprisingly the yeast worked with the pressure, definitely not as much banana and pepper as I was hoping for but enough maltreatment stress on the yeast to upset it a bit.
I did follow the advice in the above link for a more clove mash.
Next brew though it's an open ferment at least until 10 gravity points off finish.

 

[odie]

It appears I have reached terminal gravity. Took a sample. 1.007 Last time was 1.008 I think I'm getting that banana...but hard to tell for sure at room temps in a hydrometer tube.

Won't be drinking this one until Sat...gotta cold crash and carb...but looks promising

 

[DuncB]

You've wet my taste buds, think I'll brew one this weekend.

 

[Rfox2014]

It appears I have reached terminal gravity. Took a sample. 1.007 Last time was 1.008 I think I'm getting that banana...but hard to tell for sure at room temps in a hydrometer tube.

Won't be drinking this one until Sat...gotta cold crash and carb...but looks promising

Any luck on the banana quest?

 

[odie]

yep...just NO PRESSURE until a few/several days into it.

 

[Indian_villager]

My guy, you did a lot of what I do to favor the clove side.

If you want banana, beat the **** out of the yeast.
Favor a mash that is more wheat than barley, barley brings more ferrulic acid which converts into clove.
WLP300 Pitch about 88billion cells, use any of the available calculators to figure this out. Honestly a single pack should be enough for 5.5 gals @ 1.047OG
Ferment warm 22C
Don't pressure ferment it. Once you've hit OG let it sit at 22C for a week or two.

Best of luck

 

[beersk]

I made the mistake in summer '22 fermenting a hefe under pressure. It resulted in an undrinkably sulfury beer. It got dumped. I like pressure fermenting, but it does tend to trap in a lot of that sulfur or other bad compounds that should blow off. Best way to get around that is to start the first few days at 5 PSI or so. It depends on if it's the first pitch or a repitch. If it's a repitch, then I don't worry about it and just let it go to full pressure, which might be 22PSI for lagers if I'm fermenting at 60F.