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Beer Flaws


Welcome to another edition of Ask the Beer Guy. This is your host, John Griffin, the beer drinking professor.

Today we're going to talk a little bit about flaws. Most of this will be pretty evident. I made the slides pretty verbose, but I'll go through them anyway. One thing I really want to stress is a flaw is a flaw until it's not really a flaw. Sometimes these are just general comments, sensory comments. What may be a flaw in one beer may not be in another. The lesson really to anybody in beer, including my class, make sure it's really a flaw. The only way to do that is to know your styles.

We'll talk about them in alphabetical order, the most common ones. Acetaldehyde, you can pretty much get that, fresh cut green apples. It sometimes has green grass, latex paint, very common in green beer, in order words, beer that hasn't been aged long enough, a really fresh beer, can sometimes be caused by bacterial spoilage. But again, remember a flaw is a flaw unless it's not. It's acceptable in some Belgian styles. It's also acceptable in American lagers. For example, Budweiser pulls their beer off the yeast a little early, and it leaves that green apple flavor.

Alcoholic: People would laugh sometimes when I say that, but it's not really a flavor. It's more of a spicy, venous character. The aroma and the taste isn't warm. It's usually a prickly mouth feel. Of course, it's acceptable in some styles, barley wines, bock beer, other high alcohol beers, but it's not acceptable in beers that are not supposed to have high alcohol. Again, most commercial beers, in fact, I've never found one that had alcoholic as a flaw, but if you're in home brew, you're making your own or you're judging them, remember what the style says. If it's supposed to be a 5% alcohol beer, and you can feel the alcohol on it, because it's 8%, or 9%, or 10%, then you'll know that's a flaw.

Astringency: we'll get that at times, puckering, lingering harshness, other dryness. Sometimes it's graininess. Usually it's caused by the beer not being mashed correctly, the temperature too hot. Again, it's going to be mostly in home brewed beer, not commercial beer so much. Sometimes spices such as coriander, orange peel, and cinnamon also contribute astringent flavors. Christmas beers, holiday beers, and some Belgian beers have those spices added.

Bitterness: in the age of IPAs, most people think bitterness is good, but again, it depends on the style. Sometimes malts cause the bitterness, and sometimes it's due to putting too much hops in. Usually that would be the case. Excessive bitterness is perceived as a harsh, dry taste in the back of your tongue, back of your roof of your mouth, as opposed to the roasted malts, which tend to be up in the middle of the mouth. It's appropriate, again, in barley wines, IPAs, sometimes in robust porters and dry stouts, but usually that's if they have too much roasted malt.

Diacetyl: this is a big one. You'll get this a lot. It's artificial butter, butterscotch, or toffee aroma. Sometimes it's perceived like a slickness on the tongue. Not everybody, I think they said only about 60%, 70% of people can actually get the aroma of diacetyl or the flavor. But you can almost always tell when you run your tongue on the roof of your mouth, you'll feel a slickness on the roof. Most lagers do not have diacetyl. They do what's called a diacetyl rest. They'll bring the fermenting beer up to 50, 55, maybe even 60 degrees for a couple of days. That gets rid of it, because the yeast becomes active and gets rid of the byproduct. But it is acceptable in Bohemian pilsner, or Czech pilsner, and in some ales. Again, check the style.

DMS: dimethyl sulfide, it's sweet corn aroma like canned corn, cooked canned rotten vegetables. Low levels are acceptable and appropriate in most lagers. I've never seen an ale style where it's desirable. Again, it's due to the colder fermentation usually. 

Esters: now this we're getting into a term, and it's also could be a flaw. Esters are fruit. Instead of calling it fruity, you can say it's got fruity esters is the correct way. Sometimes it's floral, roses. High levels, they could take on solvent notes if there's too much fruit and the sugar's all out of it. The aroma just becomes the essence of it, and it can start to smell like solvent. They're acceptable in ales, Hefeweizens and Belgian ales, specifically. I say that as German Hefeweizen, not the American wheat beer, which some people marketing-wise call Hefeweizen.

Grassy: freshly cut grass or green leaves, usually it's oxidation of alcohol. Some hops are grassy, but you shouldn't really smell like it's a cut lawn. That could be usually more like an older, dry grassiness.

Husky: grainy, you probably will never get that except in home brew, but for the interest of including everything, it's spent grains, over crush, over [inaudible 00:05:58]. That means they went and pulled out too much of the sugar, so they actually started pulling out the bitter components. Some lagers might have a little bit of that, but it's not really appropriate in any ale again.

Lightstuck: we also call that skunky, usually stored in green, clear bottles. It has to do with the hops ultraviolet light cleaving and isohumulone molecule in combining with the sulfur compound. It's never acceptable. It's always a flaw, even though Heineken and most other green bottle beers have that flaw.

Metallic: tinny, coiny, blood-like flavor, sometimes you'll get that in a commercial beer, not very often. It is common in ... not common, it's a common flaw in home brewed beers, but it's not a common issue, luckily. Most home brew doesn't have that. Sometimes iron levels in the water are a primary cause, but it's usually an equipment failure at some point. Blood-like flavor sometimes in some commercial beers, that's usually a storage issue.

Musty: stale aroma and taste, it's the oxidation of malt compounds in the melanoidin family. Some beers, such as Bière de Garde Belgian style may have that. Sometimes when it's musty, it might get a little better, but usually once they become musty, if it's not part of the style, it usually will not go away. You can use it to cook or just rough it out and drink it. It won't hurt you.

Oxidized: stale beers, we get this a lot, a lot in commercial beers, probably more in commercial beers than in home brew, because home brew tends to be drunk quicker and stored close to the source. But it's winey, cardboard, paper, sherry-like aromas. The higher the alcohol of the beer, the more sherry like it becomes. It actually become an asset in a very high alcohol beer that's aged well, but generally, they're not. It's from oxidation. Almost all beer, especially in bottles, has a little bit of oxygen in it, no matter what. 

It's a common flaw in many older [inaudible 00:08:10] commercial beers. Almost all English beers by the time they get here in a bottle have that issue. Same with some of the Mexican beers, Negra Modelo, for example. I have not had one that isn't oxidized in many, many years. Unfortunately, people think that's what they're supposed to taste like, and they don't. If you drink at the brewery, you're close to the source. You'll find out what those beers are really supposed to taste like.

Phenolic: so here's another term that also can be a flaw. Phenolic is the opposite of estery. Well, not the opposite. It's the other side of the coin, so now it's smoky, plastic, clove-like, spicy flavors, as opposed to fruit. Clove and smoke are obviously acceptable in certain styles, Belgian ale, rauch or smoke beer, some Scottish smoke beers. Of course, Hefeweizen, they be fruity, they may be phenolic, they may be both, depending on the yeast used and the age and other things. Again, make sure that it's not supposed to be part of the style.

Sherry: again, this is the good side of oxidation usually. It gets dry sherry, fruity, alcohol flavor, sometimes almonds or hazelnut notes. It adds complexity to older, big alcohol beers, barley wines, old ales, Scotch ales. In almost every other style, it would, of course, be a defect, because you don't want the oxidation. You want more of a fresh alcohol flavor if you can get it at all.

Solvent: you sometimes get that. In fact, there's one beer in particular, Old Ale, which is an English style, Theakston Old Peculier has that. The aroma and flavor of higher alcohols. They're also called fusel alcohols. They're generally undesirable. Lacquer thinner, of course, who wants to taste that? But in most styles, again, they are not part of the style and would be considered a flaw. Depending how bad it is, they may not even be drinkable.

Sour:  sour and acidic beers are usually a flaw. The tartness, and aroma, and flavor can be sharp and clean by galactic acid, which you really can't smell. You'll get no aroma of lactic acid, but you will get the sharp, clean, sour taste, acidity, as opposed to vinegar or lemon, which you can generally get as both aroma, and of course, flavor. It's generally a sanitation problem. The yeast has gotten run over by non-good yeast, usually bacterias that you don't want in there. But it is acceptable. Berliner Weisse and Belgian lambics as well as Flanders ales, they're supposed to be sour. In that case, it would be acceptable.

Sulfur: we don't get this much. Again, it probably would be in a home brew, rotten eggs, burning matches, usually a yeast problem, bacterial spoilage. I guess it could be water contamination, but most of the time, at least in the world where we get our water, and it's not coming out of a river or a lake, it's probably not water contamination. It's, again, not desirable in any style. 

Sweetness: generally is not a flaw, but it could be if it's too sweet. Low attenuation, remember, attenuation is the ability of the yeast to convert alcohol. Flocculation, if it's low flocculating, it's left some of the yeast in there, generally poor yeast health. The yeast didn't get a chance to eat all the sugar that was in the work in the unfermented beer. Appropriate level is style dependent. Again, there are some beers that should be sweet. The stronger ales and lagers generally have more sweetness, because the alcohol also helps, as we've mentioned before in the sherry-like category to make things a little sweeter. Again, check your style. If it's an IPA, and it's sweet, there's probably something wrong.

Vegetable: that's cooked, canned, or rotten vegetable aroma. Very seldom see that. It's also part of the other flaw we mentioned above.

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