Excuse Me, But This Beer Taste Like Skunk
Posted by Bob Skilnik on March 5, 2007
Beer is a perishable product than can suffer from negligence at the brewery or abuse by distributors, retailers, and even beer drinkers. With the almost limitless choices of beers on store shelves afforded by the availability of American brews and the importation of beers from Algeria to Zaire, beer drinkers now experience more variety—but face more pitfalls—in their beer purchases today.
A study at the University of North Carolina has scientifically confirmed what brewers have known for over a century—light can affect the flavor of beer. Since aluminum cans and draft kegs are impervious to light, this phenomenon is only found in bottled beer. While early American brewers used trial-and-error to determine that brown bottles offered the best protection from light for their products, spectrographic analyses of light wavelength and glass color have concluded that early Braumeisters were correct in their assumptions; brown bottles absorb light and thus protect beer. Green bottles, however, allow some light to pass through, while clear glass offers little protection. Despite this evidence, today’s bottled beer can still be found in clear, green and brown bottles.
Scientists at the university subjected isohumulones, a grouping of chemical compounds found in hops, to laser beams in order to simulate what often happens when beer is exposed to visible or ultraviolet light. The result was the formation of a chemical component known as “skunky thiol.” (The term is an accurate one since the same component can also be found in skunk glands.)
The problem of bottled beer becoming “skunked” is not limited to exposure to sunlight, as was the case during the early years of beer bottling. Probably the greatest incidences today of beer becoming lightstruck occur in the display cases of retailers where fluorescent lights are used to illuminate inventory.
The Miller Brewing Company has gotten around the issue of photodegradation of hops in their clear-bottled Miller High Life brand by using modified hop extract in the beer-making process. Rather than add traditional hop cones or compressed hop pellets to the brewing kettle to balance the flavor of the beer, Miller strips the isohumulones from the hops and reconstitutes the bitter hop properties into a modified extract, leaving the clear-bottled beer immune to the damaging affects of light. More commonly, though, breweries are beginning to ship their bottled beer in sealed cardboard cases in order to avoid skunkiness in their products.
Makes a beer drinker wonder why breweries package their products in green or clear glass at all.
“A lot of it is custom and tradition,” says Ron Extract, who heads up Chicagoland beer sales for Boston-based Shelton Brothers Importers. “The British in particular seem to have a certain propensity for flint. It is also the case that certain bottle sizes and shapes may only be available in one color. The champagne-style bottles used for a number of Belgian ales, for example, only come in green.”
“[They] are used primarily for marketing,” argues Lyn Kruger, president of the Siebel Institute of Technology, a Chicago-based school for brewers. “It is thought that clear and green bottles project a better image than brown bottles and make them more distinctive on the shelf.” Kruger, who worked as a research microbiologist for South African Breweries (SAB) before heading up the local brewers school, doubts if breweries that bottle in green or clear glass would ever switch over to the more protective brown bottles. Many beer drinkers, says Kruger, “have come to expect this flavor. The brewery would not want to change the packaging as the consumer may react negatively to the lack of this flavor.”
Extract agrees with Kruger’s assessment. “Apparently, many consumers like this [skunky flavor].”
Wet Cardboard, Musty
Like all foodstuffs, beer has a limited shelf life. Breweries such as Anheuser-Busch or the Boston Brewing Company use “born-on” dating or notched calendar markings on their beers’ containers to alert the consumer to the age of their products. Age can lead to the enhancement of undesirable compounds that might have been lurking in fresh beer, though at levels so low that they were immeasurable at the brewery. Even with shelf-stabilization processes such as pasteurization or micron filtering, beer will eventually deteriorate, especially if stored for extended periods of time at room temperature or warmer.
“Some consumers are not aware that leaving beer in the trunk of their car and driving around for days or storing their beer warm will accelerate oxidation,” says Kruger.
Aside from warm storage of beer, improperly sealed bottles or cans, referred to in the industry as “leakers,” can cause damaging air to seep into sealed beer, eventually turning fresh beer into an undrinkable product. This same problem can sometimes be found with corks used in the bottling of the more esoteric beers such as Belgian lambics. These beers are bottle-conditioned, similar to the methode champenoise used to carbonate fine champagnes, with a secondary fermentation taking place in the bottle. As with champagne, a deteriorated cork can allow air into the bottle and impart a taste of old cork to the beer.
Three months is normally the maximum life of a properly sealed beer, especially lagers, though a high-alcohol or highly hopped brew can last for years. As a rule of thumb, however, the hint of any beer tasting or smelling like wet cardboard, dank must, or even old leather, indicates a beer that has reached the end of its life.
Even after a fresh barrel of draft beer leaves the brewery, is held at a proper temperature by the distributor and rolled gingerly into the beer cooler of a bar, problems can still occur in the beer, especially if the draft lines to the tap are not clean. Without a regular cleaning regime, draft beer lines often build up a coating of yeast, most often when a beer such as a hazy, yeast-laden wheat beer has been run through the tap. Without a thorough cleaning of the draft line after the barrel runs dry, especially if the next beer hooked-up is a clear one, the result can be an unappetizing beer with very apparent chunks of old yeast floating in it.
A more commonplace defect with beers hooked up to a dirty draft line, however, is the flavor of butterscotch or butter in the beer. Though the taste is not necessarily an unpleasant one, it’s often a sign of a beer gone bad. “This happens either because the draft lines are not cleaned frequently enough or because the beer is on tap for too long,” says Lyn Kruger.
“We have the draft lines cleaned once a week,” says Chad Wulff, manager of The Map Room, “and run the same style of beers on the same lines to avoid possible flavor or cross-contamination problems. Wheat beers stay on the same tap, for instance.” The bar on Armitage serves up twenty-six draft beers. Noting the importance of keeping more than a score of draft beers fresh, Wulff notes that “If we could have the lines cleaned daily, we would,” but concedes that “it’s just not possible.”
So what should a beer drinker do to avoid possible problems with their beer purchases?
· If considering the purchase of bottled beer at the liquor store, stick with a brand that uses brown bottles, sealed cardboard containers, or cans. If your favorite drinking establishment also serves green or clear bottled brands on tap, try to sample these products on draft rather than from their bottle.
· Put packaged beer into the refrigerator as soon as possible.
· See a new beer on a tap handle but you’re afraid you might not like it? Ask for a sample. “We’ll always give a customer a sample of any of our beers,” says Map Room bar manager Wulff. “Some of our Belgian beers are sour,” a positive attribute for the style, but one that a less experienced beer drinker might not expect—or enjoy. Brewpubs customarily offer a small multi-glass sampler of their beers. Order one before getting a possible full-sized disappointment.
· Check the expiration dates on beer containers, just like you would on a gallon of milk before you buy.
· Whether it’s a six-pack from a liquor store or a draft beer sitting in front of you at a bar, if you think the beer is off in flavor, let the owner or barkeeper know. If they won’t refund your money or let you switch to another beer, take your business elsewhere. Beer is a perishable product and things can go wrong no matter what precautions are taken by brewers, distributors, and retailers.
Experimenting With Skunky Beer
Skunky beer is probably the number one fault in the flavor of beers today. Ironically, many beer drinkers confuse skunkiness as part of a beer’s flavor profile. Here’s a two-phase home experiment that will make you more aware of the characteristics of a lightstruck beer:
Go to your favorite liquor store and purchase a sealed and chilled six or twelve-pack of either a green or clear-bottled beer. At home, put all the bottles into a refrigerator except one. Put this single bottle on a sunny window sill and let it sit for a day. The next day, put it into the refrigerator with the other bottles, but keep this bottle on a separate shelf so there’s no confusion. When the beer is cold, take out the sun-struck bottle and a control bottle of beer that went directly from the sealed case to your refrigerator. Open up the control bottle and take a sniff. Pour a half-glass of the control beer and taste it. Now do the same thing with the sun-struck beer. That’s a skunked beer!
For the second phase of this very unscientific home experiment, combine the rest of both half-empty bottles into a third glass and smell and taste the beer. It should taste reminiscent of a clear or green-bottled imported beer. Although this is a taste that most American beer drinkers associate with an import beer, it is not how the beer tasted when it left the brewery.
More About “Off” Flavors In Beer
With a little practice and the guidance of a more knowledgeable beer-drinking friend, you’ll be able to discern what makes a beer off in flavor. There are a myriad of instances, however, when the off flavor found in one beer style is exactly the flavor profile wanted in another.
Butterscotch, buttery—In a lager beer, this taste is undesirable, sometimes a sign of a too warm fermentation. In draft beers, this common defect can also be triggered by the beer being infected by lactic acid bacteria. This odd flavor can also occur in a draft beer that is old or hooked up to a dirty draft line. A butterscotch flavor, however, is often desirable in certain ales. England’s Whitbread Ale is a good example of an ale with high notes of butterscotch.
Hot or alcohol/solvent—An especially unwanted flavor in light-bodied, golden-colored lager beers, but desirable in high alcohol beers like Goose Island’s Bourbon County Stout or Sierra Nevada’s Bigfoot. Fruity—Another flavor found more often in ester-rich ales, but not wanted in cold-fermented lagers. Three Floyds Brewing Company of Indiana brews the highly hopped Alpha King, an ale, that has a refreshing nose of grapefruit and banana. While this adds to the overall enjoyment of this beer style, it’s not desirable in golden-colored lagers.
Hazy—In an unfiltered wheat beer, a cloud of yeast lingers throughout the beer, expected in this style of beer. As with most wheat beers, one can also note a distinctive smell and taste of cloves and/or bubble gum. In any brew but a wheat beer, however, these attributes would indicate a beer gone bad. Sour—A sure sign that a typical lager or ale has been infected by wild yeast rather than fermented by a pure laboratory-cultured strain. In contrast, the fermentation of tart Belgian lambics begins with the deliberate introduction of up to twenty or more different strains of wild yeasts to the beer. Cantillon Gueuze is a good example of a sour but complex blend of lambic beers. The wild yeasts used in this ale are peculiar only to a particular region in Belgium. In the US, Wyeast Laboratories, Inc., actually develops and sells wild yeasts for the brewing of Belgian-styled beer here at home. Lactic acid bacteria is a key component of these blended strains of yeasts.