I am not a huge drinker but am concernec about something. I will buy a 6 pack on a Friday. If I don’t get around to drinking it it will be skunked by the next weeked. Everytime.
Is this too fast? How long does yours keep? What can I do to make it last at least 2 weeks?
Don’t open the can/bottle?
It will last a long time if you keep it sealed, cool, and away from light (like, in your refrigerator). If you let it get warm, or if it is a bottle and left in sunlight, it will (may, actually, there are other variables) in less than one day.
Depending on the type of beer, and how its been handled up until you purchase it, it could even be skunked before you get it home. “Skunkiness” results from light (especially sunlight) penetrating the bottle and interacting with some of the components of beer. Green and clear bottles are very susceptible, brown less so. In my experience imported light lagers in green bottles are very prone to skunkiness (Molson, Heineken). They generally take the longest time to get from the brewery to you, and so are most vulnerable. Your best bet is generally a local microbrew (or at least a mass produced domestic beer) in a brown bottle. Keep it cool, in the dark, as AZCowboy says.
You need me to be your friend. I believe in consuming beer before the ink on the label is dry. 
“Leftover beer?” What is this “leftover beer?”
Are you sure your beer is skunked? I mean, maybe you just don’t like beer. Otherwise, there is something wrong if beer is going bad in less than a week in your frig, EVERY time you buy beer. Sure, we have all gotten that bad sixer of Becks from the gas station that has probably been on the shelf for a year, but to have beer go bad every time you buy it is not normal. Are you leaving it in the kitchen window or something?
No. I leave it in the fridge which is nice and cold and dark. I do like beer quite alot actually. The stuff I buy is called Avalanche and it is not a micro brew but is not a national brand either. Its good stuff.
Alot of times I will hit the liquor store during the day just to have beer for that night in case I want it and then I end up not drinking any and it sits till next weekend.
I am not sure that it is going totally skunked, but it does taste different after a week in the fridge than it does when I drink it right away. Different enough that I don’t like the taste.
Avelanche? Breckenridge Avalanche? Yes, it’s a microbrew; you’ll get some very mixed opinions on this beer; some people like it because it’s sweet, others dislike and say it has a nasty bitter chemical aftertaste. Some even say that Breckenridge is the worst microbrewery in Colorado.
If it tastes any different after a week in the fridge, something is terribly wrong with it. Maybe the bottles aren’t capped properly, or maybe they aren’t filtering or pasteurizing it.
I’ve also heard this about beer, maybe someone can confirm/deny:
Regarding temperature, you can store beer at room temperature for a good long time, but if you put it in the fridge, get it cold, then take it out and let it get back to room temperature, it will taste bad when you get it cold again. IOW, don’t let the temperature fluctuate a lot.
Permitting a cold beer to become warm is most definitely ‘alcohol abuse,’ IMHO.
The worst beer for ‘skunking’ I’ve run across was good ol’ Miller High Life in those lovely clear bottles.
You need to buy better beer. The group I bike with is always on the look out for the holidays or winter brews. There’s more alcohol content along with the cost, but they do last for a good year or so. The barley wines will last for several years, they just get better with age.
My favorites: Deschutes’ Black Butte Porter, Fuller’s Vintage Ale, Full Sail’s Old Boardhead. ummmm, beer.
Considering the beer is probably sitting in the store for at least week or a month before you buy it, I doubt that it is going skunky (i.e. sulferous compounds released) in your fridge.
I have found that my sensitivity to certain flavors changes from day to day. A favorite wine or beer can taste fine one day, then taste off the next day, then taste fine again. Metabolism, hormones, other foods eaten?
Most likely your roommate is drinking it while you’re out, refilling the bottles with something else, and recapping them. I have the pictures to prove it.
www.xxxvoyeurcam.com/beerthief
“Not a good experience with this beer. Tasted almost rancid, and quite sour. Watery, and played bad on my tongue. Probably the worst “micro” found in Colorado.”
http://www.ratebeer.com/ShowBeer.asp?BeerID=2226
Also, I’m not sure why, but several of my homebrews have tasted far better at room temperature than out of the fridge. If Avalanche is a darker beer (brown ale, scotch ale, porter, stout), despite TBone’s opinion, try letting it warm up for a while before drinking it the following weekend. I’m not sure if my sensitivity to certain flavours changes with temperature, but I have had some batches that taste like they’re close to going off at fridge temp, but taste perfectly fine at room temperature.
I used to work for an Anheuser-Busch distributor, and I know for a fact that the temperature fluctuations do not cause beer to change taste. ALL of the beer was stored in a refrigerated warehouse, and was cold enough to drink when it left the warehouse; retail stores would then put some in the cooler, and put some on the shelf, where it would be sold at room temperature. Even if you bought it from, say, the cooler of a liquor store, it may have been sitting back in the stockroom for several days, warm, before being re-refrigerated.
This went against everything I’d ever heard about “skunked” beer, but it’s pretty well-known and accepted as fact within the beer industry.
No beer should go bad within a week or two; 110 days for canned or bottled beer is the Anheuser-Busch standard for freshness, and 120 days is common for most other breweries. (Kegs, however, are only fresh for about 45 days.) If it is going bad, the culprit is almost certainly some improper bottling technique.
Since Whiskey mentioned Anheuser-Busch (note the irony there, given your user name), it might be worth considering whether the answer to this question (the OP) varies depending upon the manufacturer. IANA bottler, but I believe that the major U.S. breweries put preservatives into their beer, which allows them to remain ‘drinkable’ (relatively speaking) despite being moved in and out of refrigeration. In contrast, foreign and microbrewery beers don’t have the same preservatives, which makes them somewhat more susceptible to going bad if they get warmed up.
Conveniently, it turns out that I’m allergic to the preservatives used by Miller and Anheuser-Busch and other major bottlers, so I limit myself to quality beers and get no headaches or stuffy noses any more.
“Skunky” taste (lightstruck flavor) in beer is a result of photodecomposition of iso-alpha-acids (isohumulones). Isohumulones in beer come from hops and are primarily responsible for giving beer a bitter taste. It is possible that your Avalanche brew is high in these compounds?
More than you could possibly care to know about how beer skunks. (262K PDF)
I’ve had home brew last over a year and a half and be perfectly fine.
I gotta get back into homebrewing…