While I'm very sensitive to diacetyl, I'm a bit worried that I'm completely insensitive to acetaldehyde. I had two people tell me at two different times in two different beers (both Belgians) that they sensed it in there, describing it as cidery, or even apple sauce. I've had a few cidery beers before, but I did not think this was acetaldehyde I was tasting. The first beer was a wit, and I used chamomile and grains of paradise as spices, so I thought that maybe the commenter couldn't pick out the spices and described it as a flaw as a result. The second beer was a saison, and I thought it was fairly fruity, and more like juicy pear, not at all like a flaw. But I had my doubts once he mentioned he thought it was cidery. I know acetaldehyde is supposed to taste like "green apple" - this is not a taste I am getting in these beers. Are there any other descriptors that I could use to distinguish between Belgian esters and acetaldehyde? Anyone else have a blind spot for acetaldehyde? Is acetaldehyde more likely to occur in Belgian ales than others? I should also mention that I had many others try this particular saison and no one else commented that the beer was cidery - many thought it was good. Yes, I tend to harp on and analyze criticism much more than positive feedback.
Far from a blind spot for me, as I seem to be hyper sensitive to it (we tried an off flavor kit and I picked it up in a blind test at 25% of the normal threshold). Its present in small, detectable amounts in some american light lagers (Bud comes to mind) and Franziskaner (I get it big time in this beer). I've never associated it with Belgians, especially since the long lagering for many of them and bottle conditioning will remove it. Green apples, grassy and cidery are all descriptors I'd associate with acetaldehyde, although the green apple flavor is the one I pick up most clearly. Also some people state that they smell fresh pumpkin or rotten apples. Your tasters could be associating the combination of dryness and fruity esters as cidery and green apple like. If you ever want another opinion, you can always send it to me.
Matt, Below are some extracts from Homebrewtalk that may be helpful to you? “Acetaldehyde is a compound that causes off flavors and aromas in beer, often described as tasting and smelling like green apples, cut grass or green leaves, pumpkin, or latex paint, and is sometimes described as giving beer a green character.” And: “While acetaldehyde is usually considered a fault in beer, some beer styles do use it as part of the flavor profile. The best-known example is Budweiser, but other beers such as EKU-28, Salvator and Ephemere also include acetaldehyde flavors.” As a FYI, the association of acetaldehyde with Budweiser is a misnomer. The amount of acetaldehyde in Budweiser is low; the green apple type flavor in Budweiser is an ester that the AB lager strain produces. Cheers! Jack http://www.homebrewtalk.com/wiki/index.php/Green_apples
Yes, I was going to mention this, not the part about Bud specifically, but the part about there being an apple tasting ester. Whenever someone even mentions "apple" we tend to think acetaldehyde immediately but what if in some cases it is this apple ester? What strains can produce it? EDIT: I believe said apple ester could be ethyl hexanoate (apple or aniseed). There is also ethyl caprylate (sour or red apple).
I wouldn't take the 'green apple' descriptor too far. Acetaldehyde sort of smells that way, but it smells worse imo. There are definitely other compounds with more of a green apple aroma-Sorbaldehyde smells just like a jolly rancher candy. On its own, it smells frickin amazing. Acetaldehyde is pretty nauseating on its own. There are probably esters as well that are apple-y.
“I wouldn't take the 'green apple' descriptor too far. Acetaldehyde sort of smells that way, but it smells worse imo.” Ted, what descriptor do you think is more appropriate for acetaldehyde? Cheers! Jack
@barfdiggs @FarmerTed @epk your comments give me hope. My suspicions were that the tasters were quick to judge, as I could totally see apple esters and acetaldehyde confused. After all, I have seen pear as a common descriptor for saison esters, and a pear and apple are indeed very similar! Now, that doesn't mean that the beers weren't good by their taste standards; but I do think they were just quick to call the beers flawed. I have made one beer before that I thought contained acetaldehyde (well, since a Mr. Beer kit in 2005). I made a 1.077 stout that I kegged after 9 days. I should have let it sit for a while longer before kegging. The initial aroma and flavor in the keg (not in the fermenter mind you) was of rotten apples, or rotten fruit. You could tell it should not have been there. Over the course of a month, the flavor disappeared first, followed by the aroma. And then the beer was fantastic. That is not happening with these Belgian beers. Therefore, I'll maintain (for now) that I don't think this is acetaldehyde.
When it comes to beer, you run into acetaldehyde both coming and going . . . but don't blame the Belgisch. I always thought acetaldehyde was a dastardly byproduct of fermentation and if it lingered it was a flaw. But it is a direct product of the conversion of pyruvate by yeast. Then, all ethanol is formed by the ADH conversion of acetaldehyde. That's right . . . if there is no acetaldehyde created there is no ethanol . So all of our beers have acetaldehyde in the chain of events leading up to their creation . . . same in St Louis as in St Sixtus. Then when the ethanol finds its way to your liver, it is converted back into acetaldehyde by the same ADH (think splitting headache) which is far more toxic than the ethanol from which it came. Only until acetaldehyde dehydrogenase converts it into harmless acetic acid does the pain go away . From the gist of your comments I think your tasters are struggling to come up with something to report to you. Until I tasted green apples I would ignore the unwashed masses. Be kind to Belgians . . .
Acetaldehyde is really pungent, and maybe solvent-y. There is some apple character, but a lot of simple aldehydes have a similar smell (kind of like how ethanol, methanol and isopropanol smell similar). When acetaldehyde is concentrated, you really don't want a big whiff of it.
Yeah, and they also all smell sort of alike (kind of like acetaldehyde and propianaldehyde smell similar). I didn't say they smelled exactly alike. And, yeah, my nose had been dead for 20 years, lol.
I'm definitely not very sensitive to AA. Not completely, I pick it up maybe 25-50% of the time, depending, but even with known spikes, I'll go back to the beer and still not be able to pick it up very well. Oh well.
