Banana beer.. biggest cause?

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gregmosu

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just brewed two batches: Belgian Wit & Brown Ale. Both have banana taste.

My basement stays very consistently at 64 degrees. The temp of the wit spiked up to 75 degrees on the 2nd day, so I kinda thought it might turn out this way, but the brown ale only reached a temp of 69 before I cooled it back down. It also has the same banana flavor.. I kinda figured it wouldn't be as bad. I did some reading and it seems that others suggest pitching yeast while the wort is a little too warm can cause banana flavor.

I'm still planning on getting a freezer and a temp controller for fermenting, but does pitching the yeast on wort that is over 70 degrees cause off flavor? or does holding the temp at exactly 67 degrees mean more for controlling flavor?
 
We'll need some more info to give a good guess.

Notably, how warm was the wort when you pitched, and why kind of yeasts did you use?
 
I believe the unwanted banana flavour is caused by overactive/stressed yeast, which causes it to create a lot of esters.

Most common reason is indeed temperatures above the yeast's temperature range. Some strains of yeast actually do really well in higher temperatures so it also depends on which kind of yeast you are using and what effects you are after.

Other reasons could be poor aeration of the wort before pitching the yeast or underpitching yeast/pitching older yeast.
 
Too-warm temperatures sounds like the most likely cause – even 69° is on the warm side for most of the standard clean ale yeasts.

Luckily, it's also not too hard to fix in future batches – get a 15-gallon plastic bucket, make a water bath for your fermentor, and freeze a couple of half-gallon plastic milk/OJ jugs to swap into the bath when it gets too warm. The thermal mass of the extra seven or eight gallons will keep the temperature from rising too quickly, even at the peak of fermentation; you can get away with checking it just three times or so a day.

If you're still getting banana beers once your temps are under control, then you can start looking into things like underpitching and poor aeration.
 
stressing the yeast out and warm temps will give the banana flavor. pitching temps is very important. Having a good temp the first few days of fermentation is very important. Also the right temp based on the yeast you use is also very important.
 
The only time I noticed banana character was with an ale I made from extract. It was quite strong in the first few bottles I opened but disappeared after a couple of weeks. It was most likely from higher temps as I didn't use any method to stabilize ferm temps then.
 
Are they already packaged? I just did a couple batches that had big banana aroma and flavor when I sampled for a gravity reading, they weren't yet at final gravity. After a few more days and final gravity was reached the yeast had cleaned it up nicely and no more banana.

When I say big banana aroma I mean I could smell the sample from 6 feet away, no joke... I was worried.

I will add that both times this has happened to me I had very slow fermentations in which I ended up bumping the fermentation temperature into the 70's and was periodically rousing the yeast. The first time was with wyeast 3944 (belgian witbier) and the second was with wyeast 3711 (french saison).
 
The English brown ale was a brewers best kit and the wit was something I threw together from a basic recipe on the internet. Both had dehydrated yeast packages(re-hydrated both before pitching).

Both sat in a plastic bucket for fermentation for about 5 weeks. Here are the differences in those two batches versus beer I brewed before.

1) Did not re-rack for secondary fermentation. (Sat in plastic bucket for 5 weeks!!)
2) Kegged both beers instead of bottling and letting them sit for an additional 4 weeks.


I guess for next batch I'll aerate before pitching, focus harder on keeping the ferment temp constant and re-rack for secondary ferm.
 
The English brown ale was a brewers best kit and the wit was something I threw together from a basic recipe on the internet. Both had dehydrated yeast packages(re-hydrated both before pitching).

Both sat in a plastic bucket for fermentation for about 5 weeks. Here are the differences in those two batches versus beer I brewed before.

1) Did not re-rack for secondary fermentation. (Sat in plastic bucket for 5 weeks!!)
Well, secondary isn't exactly secondary fermentation, just a secondary vessel. I wouldn't guess not transferring to a secondary was your problem.

2) Kegged both beers instead of bottling and letting them sit for an additional 4 weeks.


I guess for next batch I'll aerate before pitching, focus harder on keeping the ferment temp constant and re-rack for secondary ferm.

Wait, you didn't aerate your wort?
 
Stressed yeast is the biggest contributor to banana flavor (other than yeast strain). If it got warm, you didn't aerate, underpitched, then banana esters could have come from any or all those factors.
 
I didn't really aerate either batch. I poured water onto the wort from about two feet up, but after watching some videos, I think I need one of those drill attachments that stirs the beer up really well.

I'm also looking into a chest freezer and a temp controller for fermentation.

All in all, I think I just needed to pay closer attention to the details.
 
After you get past the first step of actually making beer, the second part is cleaning up on the details. Be aware that your tolerance for flaws in your beer will decrease in inverse proportion to the increase in quality of your beer. Basically the better you get the deeper you will mine for flaws.

You're a dog chasing its' tail at this point. Welcome to the madness.
 
I didn't really aerate either batch. I poured water onto the wort from about two feet up, but after watching some videos, I think I need one of those drill attachments that stirs the beer up really well.

I'm also looking into a chest freezer and a temp controller for fermentation.

All in all, I think I just needed to pay closer attention to the details.

LOL, SnakeRidge has said a mousefull ...

Chest freezer at Costco will cost about $190. Add a temp controller (STC1000 build at ~$50 or store bought ~$90). Don't forget to add a thermowell (~$35) and you have perfect control over your beer's fermentation temperature in the summertime. Add a heater strip for additional warmth during the winter months. Now you're set.

You don't need to aerate dry yeast. Liquid? Probably vital.

So what's the problem? All it takes is time and money! Again as per SnakeRidge: "Welcome to the madness!" :)

Cheers and good wishes!
:mug:
 
...seriously, though, $25 for the big plastic bucket, and half-gallon jugs to freeze water in are free, long as you regularly drink milk or OJ. I made half a dozen tasty, banana-free batches with this method of temp control before deciding to spend the big bucks on a chest freezer and temp controller. It's a bit of a pain in the butt, sure, but it's a viable way to see just how good your beer can be with good temperature control if $250-$300 is more than you're looking to sink into the hobby at your early stage of tail-chasing (and, in case it wasn't clear, we're all tail-chasers – it's like that riddle with the arrow getting half-way to the target, then half-way across the half that's left, then half-way across that half – the improvements keep getting smaller, but nobody ever thinks their beer is all the way perfect).
 
The first 72 hours is the most critical for off flavors in your beer. It is far better to cool the beer to below pitching temp and let it warm up after pitching than to pitch it warm expecting it to cool.

Don't ask me how I learned that this is a fact. But trust me... it is.

Cheers!
:mug:
 
Thanks again for all the advice. I'm going to try using a tub of water and pay super close attention for those first 72 hours. I will eventually try to buy the freezer and temp controller, but right now it's not in the budget. Our basement seems to keep the beer at a steady 64 degrees after primary fermentation. I guess that's the temp I'll shoot for when pitching the yeast and I'll try to keep it there until the bubbling stops.

By the way, dehydrated yeast is not super expensive. Should I be pitching two packets instead of one?
 
By the way, dehydrated yeast is not super expensive. Should I be pitching two packets instead of one?

Depends on the batch size and original gravity. You can just use a yeast calculator to tell you how many packets to use: http://www.mrmalty.com/calc/calc.html And I would just round that figure to the nearest whole packet. For example I wouldn't bother trying to pitch 0.8 packets, I would just pitch the whole packet.
 

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