gjbloom
(stranger)
07/28/04 12:37 PM
Esterification of Fusel Oils
I got to thinking about tails and how to make them tasty. (C'mon, keep it clean!) Since tails are contaminated with fusel oils, which are mostly C3-C5 alcohols, and since alcohols can be esterified to make flavoring agents, I asked Unca Google about it and turned up this interesting article. From what I gather, simple acetic acid, like in vinegar, was added to fusel oil and resulted in spontaneous esterification of the alcohols into tasiter esters (the C4-acetic ester has a pinapple-banana flavor).
So this got me wondering - would diluting some tails with vinegar and allowing the mix time to age (react) or maybe refluxing the mixture for a long time provide something palatable? Anybody up for trying it? (Me, I got no still, just desires). I imagine it would probably work best using pure (glacial) acetic acid, rather than vinegar, but what the heck - it's just some tails and vinegar.
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Blanchy
(enthusiast)
07/28/04 01:16 PM
Re: Esterification of Fusel Oils new [re: gjbloom]
As indicated in the article, the reaction forming esters from alcohols and acids is reversible. One of the things that favors the production of reactants instead of products (esters) is the presence of water. That is why they are using dried fusel oil and glacial acetic acid. There definitely is ester formation in wine, beer, and liquor, but that is in the parts per million range.
If you really want to try this and use glacial acetic acid, you need glassware and not your normal still to protect against massive corrosion.
After you made these esters, I don't really know what you would do with them. If you want the flavor of some fruit, it is a lot easier just to extract it from the fruit either as a brandy or as an essence if you are so inclined.
Chuck
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gjbloom
(stranger)
07/28/04 01:44 PM
Re: Esterification of Fusel Oils new [re: Blanchy]
The esterification reaction produces water, so it makes sense that you'd want to do the reaction without water since the presence of water would drive the reverse reaction in proportion to how much water there is. Maybe use ketene instead of glacial acetic acid and soak up the water formed by the esterification? (shudder)
Another concern is that tails are still going to be mostly ethanol, so you'd use up most of your acetic acid making ethyl ethanoate (pear flavoring?). As luck would have it, though, the longer, secondary and especially tertiary alcohols are more likely to esterify.
Another interesting possibility might be to use other organic acids besides acetic acid. Salicylic acid or benzoic acid maybe?
Yeah, it'd be cheaper and more effective to go buy some flavorings and add them to pure ethanol, but where's the fun in that?
Here is a list of flavoring agents.
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Blanchy
(enthusiast)
07/28/04 02:54 PM
Re: Esterification of Fusel Oils new [re: gjbloom]
I like the list you posted quite a bit. You are starting to get into serious organic chemistry, though, if you try to make these compounds. Fusel oil doesn't seem like a great feed stock unless you are making a lot more alcohol than your standard home distiller.
Chuck
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gjbloom
(stranger)
07/29/04 08:50 AM
Re: Esterification of Fusel Oils new [re: Blanchy]
I was just hoping to find a way to turn a sow's ear into a silk purse. Especially if it were something simple, like adding acetic acid to some tails and letting it sit.
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Blanchy
(enthusiast)
07/29/04 08:58 AM
Re: Esterification of Fusel Oils new [re: gjbloom]
The esters will increase if you just add acetic to alcohol, but perhaps not to a point where you can purify them with relatively crude distillation equipment. The best idea I still think is too mix up all your tails and redistill out the alcohol making tight cuts. Tater makes liqueur out of the product which would hide any extra fruity flavors. Activated carbon would help too.
Chuck