Beer is fermenting @ 66* ambient-- still smells banana-y

[JoePro]

Is this a bad thing?

I'm brewing a belgian double wit and a PA-- why do they smell like banana? The fermometer on the side indicates ~65 degrees and it never fermented at higher temps.

 

[smagee]

The banana level of your beer will generally depend on the yeast (as well as fermentation temp). Which yeast are you using, and has it been at 66F from start to finish? A lot of the acetyl notes will come in the first day or two of fermentation, especially if the temperature spikes into the mid 70s or higher.

For what it's worth, in my experience, the strong banana levels tend to calm down a bit with some time, which is why I tend to give belgians a bit of aging before cracking into them.

 

[JoePro]

Whitelabs 400 Belgian Wit

Whitelabs California Ale respectively

 

[BiscayneBrewing]

What yeast?

I brewed a Belgian awhile back with WLP 500 and I had a strong banana aroma as well. After reading the reviews for that strain on White Labs website it turns out that the banana smell is very typical for that type of yeast.

 

[JJL]

First, if the beer isn't done fermenting yet, quit sniffing the airlock. Yeast smells during fermentation typically aren't related to the flavor of the finished beer.

Second, what yeast are you using? If you're using a hefe strain or certain belgian strains, banana is an aroma/flavor characteristic that the yeast adds to the beer.

Finally, if neither of these is the case, I believe banana flavor is sometimes an indicator of not pitching enough healthy yeast.

 

[Homebrewt]

for the wit "WLP400 Belgian Wit Ale Yeast Slightly phenolic and tart, this is the original yeast used to produce Wit in Belgium." -white labs site so that explains that.

Not sure why the PA would have the phenolic attributes, maybe a high temp start to fermentation....

 

[JoePro]

for the wit "WLP400 Belgian Wit Ale Yeast Slightly phenolic and tart, this is the original yeast used to produce Wit in Belgium." -white labs site so that explains that.

Not sure why the PA would have the phenolic attributes, maybe a high temp start to fermentation....

It may have been a bit high at the start of fermentation, but it cooled down pretty quick.

 

[Coldies]

How quick? days, hours? I usually can get my beers down to 65 in my ferm chamber by the next morning if I brew at night.

 

[Homebrewt]

It may have been a bit high at the start of fermentation, but it cooled down pretty quick.

Yeah, that may age out of the PA with that yeast, but the Belgian is most likely going to be full of flavor, but that is what you aim for with that brew and that yeast!

-Cheers

 

[JoePro]

How quick? days, hours? I usually can get my beers down to 65 in my ferm chamber by the next morning if I brew at night.

Definitely hours.

 

[Yooper]

It may have been a bit high at the start of fermentation, but it cooled down pretty quick.

"Fruity" flavors like banana or bubblegum are called "esters". Some yeast strains produce a ton of them (like hefeweizen yeast) while others are "clean" (like the WLP001).

First, while it's fermenting you can get all sorts of strange smells, so I'd try not to worry just yet!

But, an ambient of 66 degrees may or may not be too warm. Here's why- fermentation itself produces heat. So, an active fermentation may be up to 10 degrees warmer than ambient air temperature. Also, if you added the yeast while the wort was warmer than 66 degrees, the yeast would reproduce and start fermentation before the wort ever lowered to 66 degrees. In the summer, it's really hard to do but it's important to make sure the wort is below 70 degrees before pitching, and that the fermentation temperature itself is below 70 degrees. I use some of those stick-on thermometers so I can see at a glance what the beer temperature is.

If the beer temperature is too warm, a water bath with a couple of frozen water bottles can really help keep the temperature down. Many of us use coolers, and drop in a frozen water bottle as needed to keep the temperature down.

My preference is to ferment at the low end of the yeast strain's optimum temperature range. For WLP, that's about 68 degrees but I"ve even fermented it with great results in the low-mid 60s. From White Lab's site:

WLP001 California Ale Yeast
This yeast is famous for its clean flavors, balance and ability to be used in almost any style ale. It accentuates the hop flavors and is extremely versatile.
Attenuation: 73-80%
Flocculation: Medium
Optimum Fermentation Temperature: 68-73°F
Alcohol Tolerance: High

Another thing- stressed yeast can produce esters as well. If you didn't make a large enough starter, or pitch enough packages of yeast in your wort, you could have some very stressed yeast. A "double", especially, may need three times the yeast that comes in one package.