Ethyl acetate from WYeast 1214

[beskinazi]

I made a Dubbel recently, the first I've ever brewed. At the time of bottling, there was way too much nail polish character. Three weeks after bottling, this character has decreased, but I still find it pretty intrusive. I generally followed the guidelines for Dubbel in Jamil's BYO article. I'd be interested to hear other brewers' opinions on how well the ester character might improve over the next six weeks (which is when I plan to submit it to a local competition).

OG was 1.067. Cooled to 65 °F using an immersion coil. Oxygenated as usual by banging the coil up and down in the cooled wort 200 times or so (I don't have a fancier setup, but this usually works well). Ran it into a stainless steel brew bucket and pitched two well swollen packs of WYeast 1214.

The ambient temperature was a little under 65 °F. There was no action for 24 hours, after which I set the temperature to 68 °F. Monitoring was with a probe on the outside of the fermenter, underneath a thick layer of bubble wrap. According to another thread on this forum, this works within a degree of what using a thermowell would give.

Fermentation took off on day 2, and the temperature increased to 70 °F by day 3. On day 4, I set the temperature control to 71 °F. On day 5, fermentation was nearly complete, and I increased the temperature to 72°F. On day 6, I increased it to 74 °F. I held it at this temperature for several days and then allowed the beer to decline to ambient temperature.

FG was 1.007. The ester character was so overwhelming that I fined with Super Kleer and racked to secondary. A week later, I fined it again the same way. A week after that, I bottled to give 2.6 volumes, using cane sugar and a little CBC-1 dried yeast.

 

[mashdar]

How certain are you that FV was sealed and airlock didn't dry out?

The one time I had issues with ethyl acetate was when an airlick dried out in secondary. It happened to be a 3787 quad.

If it's ethyl acetate, it likely won't improve much. Can't hurt to wait and see, though, and if it's actually fusel alcohols it may improve.

In my case, I could see how it would be a pear-like aroma in lower concentrations. Based on my sample of 1, that's how I identify it now.

 

[beskinazi]

The fermenter (SS BrewTech) was well sealed with a gasket. The airlock never dried out. According to the following article (available online), esters (including ethyl acetate) do decline during the aging of top fermented beer. The question is how much. The taste threshold for ethyl acetate is pretty high, so I can always hope for the pear-like character you mentioned.

https://www.agraria.com.br/extranet...aging_of_top_fermented_beer_1601495545047.pdf

 

[mashdar]

Am I reading that paper right that 6mo at 40C hydrolized 25% of ethyl acetate? And much less at 20C? That doesn't sound promising. But, again, the cost of waiting to see is low!

 

[beskinazi]

Yes, it's the most stable of the various esters, unfortunately. However, the paper also references earlier work that said the flavor perception is altered by the blend of all esters and fusel alcohols, meaning the presence of something else can cause the remaining ethyl acetate to come across differently. Like pears, hopefully, but who knows?

There will be not only ester hydrolysis but also some transesterification between fusel alcohols and esters (not as much as in a sour beer, though), thus creating additional new esters and alcohols. They will all be individually below their flavor thresholds, but the authors say that in combination they can cause new flavors to emerge. I'm not sure how that works, but we'll see...

Thanks for the input.

 

[hottpeper13]

We barrel aged a Tripple for way too long and got the nail polish. I kegged 5 gal and we bottled the rest in cork and cage at 3 vol. I had to dump the keg but it was reduced in the bottles that are drinkable but I won't share. I think mine was oxidized in the barrel and re fermentation in the bottle scrubbed some out.