Today we're talking about beer taints. Yup, beer taints. Sure this has to do with flavor* but right in the middle of my poking-around for info on the "smell of rain," I seduced by this lexicon of bad beer problems that you can buy to help you make better beer, and just to be a better beer drinker in general. (If I can recognize more of the features of the beer I'm drinking, does that make me a better beer drinker?)
Another term synonymous with beer taint is staling compounds, or simply "off-flavors." Regardless, oxidization is the culprit. In fact, oxygen messes up lots of things, like apples, avocados, and even your body. (You know the old joke of how "Scumbag Oxygen" is required for you to live, yet kills you slowly.)
In beer, oxidization can happen for all kinds of reasons, from air trapped in the head space before putting the cap on, to how long it's been in the bottle, to the storage conditions.
The bottom line is, we want beer to taste good, so if you're making it, we want you to know how to recognize the bad stuff. That's where the test kits come in.
It seems like the concept isn't too old, starting maybe circa 1995 by a gentleman named Dr Bill Simpson working at the Brewing Research Foundation in England.
I'm getting all this at the AROXA site. They make flavor standards and sensory software for beverages. And for beer taints.
I'm taking the following lexicon from their beer taint kit. However, I'm adding some descriptions from a few things I found elsewhere; these extras are separated by a semicolon. And I'm doing this because sensory lexicons are great. This one doesn't have any common names (except for Geosmin), but we'll have something to say about that below.
AROXA (etc) Beer Taint Kit:
“Chlorophenol, like antiseptic mouthwash”
“geosmin, like sugar beets or damp soil”
“Earthy, like green pepper"
“Earthy, like potato skins or dug soil”
"Catty, like blackcurrant juice or tom cat urine"; 2,5-dimethylpyrazine - catty, tomato plant
“Earthy, mouldy, like peat or compost”
“Alkaline, like caustic or detergent”
"Musty, like corked wine with a rubbery overtone”
“Musty, like corked wine or a damp cellar”
"papery" at the threshold concentration, "cucumbery and green-malty" at twice that value, and "fatty and leathery" at three times the threshold value; I'm adding this although it's not on the AROXA list, because it shows how different concentrations affect perception.
"moldy, earthy, tobacco-like;" and this one because it is an oxidized form of humulene.
|Dr. Morten Meilgaard’s Beer Flavor Wheel, 1970s|
AROXA has all kinds of flavor standards; I'm only copying the ones for bad beer.
FlavorActiv is another name I should mention, being that they declare themselves the global beverage industry standard for sensory needs since 1996, and have something to do with AROXA.
They make reference standards as well, and have a lexicon of 57 flavors.
And finally, I have to add my favorite word found on this topic - Lightstruck! It's another word for "skunked."
*Let's not forget, however, that most of what we taste is smell. If it's not from the sweet-salty-bitter-etc profile, it's smell we're talking about. But we'll let this slide.
Other important entities in the beverage industry:
Camden BRI - providing practical scientific, technical, regulatory and information support (also selling a beer taint recognition kit)
Siebel Institute of Technology - in the North American yeast-brewing business since 1872 providing all kinds of services (also have sensory training kits)
Here's a book about all this:
MJ Saxby, 1996
And you can't talk about beer without mentioning coffee:
(Yet I leave out all the wine stuff for another day!)