How to coax esters?

I really dont know much about how to manipulate yeasts to derive specific flavors and wondered if there was a good resource that delves into this topic? I've read some threads here and from what I understand temperatures play a dominant part in generating certain flavors, but are there any methods or process I can do to extract specific flavors (and not just a blend of flavors) from a yeast?

My intention is to try and generate a lot of natural "banana" esters, without creating very much clove or bubblegum. I assume there are specific strains that would highlight certain flavors over others, but how can you manipulate it so that you create that one dominant flavor instead of a more complex blend?

Also, is there timing involved in the fermentation process for when to reap the most benefits from certain esters?
I'm going a little outside of my comfort zone for an idea I have, but I really want to give it a try "just to see". However, I'd love to have as much knowledge to proceed so I have the potential for more success than failure...

I know with belgians they do it by fermenting at warmer temps ~80F. Other than that I don't know much on the issue except using different yeast strains. I'm interested as well. Hopefully someone has a good source or personal info.

I think you'll want someone to provide a yeast strain that matches your desired result.

I'm not sure what that would be. But the yeast is the most important thing. Generally speaking, each strain will have a range of flavours that it is capable of producing. The biggest way to affect an individual strain is temp, generally, higher temps produce more esters, but that can also lead to problems like higher alcohols. And in your case there's no guarantee that higher temps won't produce more clove and/or bubblegum than it will banana.

Producing more 'banana' isn't as simple as lowering or raising the temp unless you are talking about a specific strain.

Perhaps someone can add to that though...

Yeah, and I'm completely clueless about the subject which is why I dumped it here.

I know some of the labs acutally work with the pro's to design and "coax" strains into producing flavor profiles they desire, so I wonder what information or methods homebrewers use to try and achieve similar results..

Try WLP300.

My intention is to try and generate a lot of natural "banana" esters, without creating very much clove or bubblegum. I assume there are specific strains that would highlight certain flavors over others, but how can you manipulate it so that you create that one dominant flavor instead of a more complex blend?

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I recently did this in my tripel for which I used wyeast 1214, which I believe is the same yeast strain as WLP500. I read somewhere, probably here, that fermenting at around 68F will tend to give off more banana esters, while closer to 72-74F range will result in spicer clove esters, and that naturally you can control the fermentation temp between those two points to blend the ester profile. I did 10 days at 68F on that batch and sure enough it has very strong banana esters but not so much clove, if any.

I think this is possible within reason. In general, a good way to get an overall increase in esters while keeping other flavor-active compound levels low is to pitch at a relatively low rate, start the fermentation on the colder end for the strain, then allow it to warm up to the higher end of the yeast's range (or slightly past). The timing of this is specific to individual yeast strains and is probably fairly experimental, but if I were doing it, I would allow it to slowly warm up just after fermentation has become active. This would likely lessen the production of sulfur compounds and fusel alcohols, while allowing esters to be made.

The specific ester you're looking for is iso-amyl acetate (banana). I believe Fix discusses this ester in Brewing Science and Practice, but to what extent, I don't recall. But I'm sure you could find a pitch rate and temperature schedule that could facilitate the production of this ester in a yeast known to produce this ester significantly.

menschmaschine said:

I think this is possible within reason. In general, a good way to get an overall increase in esters while keeping other flavor-active compound levels low is to pitch at a relatively low rate, start the fermentation on the colder end for the strain, then allow it to warm up to the higher end of the yeast's range (or slightly past). The timing of this is specific to individual yeast strains and is probably fairly experimental, but if I were doing it, I would allow it to slowly warm up just after fermentation has become active. This would likely lessen the production of sulfur compounds and fusel alcohols, while allowing esters to be made.

Click to expand...

This is what most (all?) Belgian producers do, but perhaps only allowing it to rise to around 70 or so would keep the clove esters down, as suggested above.

Wonderful information.

Hopefully the idea will sprout into something plausable, and I can post back some of my results. Admittedly, I'm a lazybones so any input from others on how to reduce my trial (and error) time is a big help.

Thanks.

Good advice in here.

For banana in a hefeweizen, I would ferment in the low 60s for the first couple days of active fermentation and then let it warm up to 70°F as fermentation continues.

Definitely use WLP300.

I think the problem you might have is that human perception of flavor is not simply linear. From what Ive read as the concentration of most flavor compounds increases the flavor doesnt simple increase but changes too. iso-amyl acetate tastes banana like at lower concentrations but bubblegum like at higher concentrations, similar to diacetyl, buttery in small amounts and rancid in larger amounts.
There might be a way around this problem. various salts and other things like residual sugar will enhance flavors, maybe some specific water salt additions will bring out the banana?

I suppose you could always chop a banana into a few chunks, bake it at 300 for ten minutes to sterilize and get a nice baked flavor, then toss in in the fermenter.

"How to coax esthers?"

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