"Skunked" - Truth or Rumor?

I know the rule of thumb in these parts (which I'm following) is that we have to age the beer for at least 3 weeks before it reaches acceptable potential. Then you put it in the fridge for several days or so. Finally it's ready to be popped open and you're able to finally try out your creation. It tastes great so you decide to put half your batch in the fridge so it's ready for consumption. Now you decide that you need room for food and other items. So what happens if you take some beers out? I hear about the "skunked" rumors, but how would a commercial brewer be able to stock shelves with their beer with out proper refrigeration conditioning if this were actually true?
TL;DR: Would my beer have some off flavors if I refrigerate, take it back out and into room temperature, then refrigerate again?

Skunking happens when light strikes the beer. UV light decomposes the alpha acids in beer and one of the decomposition byproducts is literally the same compound excreted by a skunk. That is why it is called skunking.

This is an easy and fun experiment to learn about the flavor: take two beers, leave one out on the counter but out of the light, pour the other and put the beer in direct sunlight for about 20 minutes. Then crack the preserved beer and taste them side-by-side. It is pretty striking.

To avoid skunking, simply keep your beer out of direct sunlight. Brown bottles also filter out the majority of UV rays and reduce the risk of skunking. Commercial beers can become skunked and do all the time. That is why a good beer store that knows how to handle product is a good thing to have.

*edit* redatced because revvy was hatin'

As far as poor temperature controls, the biggest factor is oxidation. Limit O2 exposure post fermentation and try to limit the amount of yeast and trub in the bottles. Both of these things will help with stability.

As a general rule, your homebrew will be better stored and treated than any beer you consume from a store.

Light is what causes skunkiness, the interplay between light and isomerized alpha acids in the beer from hops, NOT changes in temperature. That's one of those old wives tales our grampa's believed that isn't true. Heck you don't know how many heat/cold cycles the commercial beer goes through before it gets into the cooler at your local stop and rod, and yet manages to taste fine.

It's only when it's exposed to sunlight, will it go skunky.

OK. So it will affect the flavor if I refrigerate for a couple of weeks, take it out of the fridge and store it in a dark, cool place, then refrigerate again? I'm not just talking about skunkiness, I mean any off-flavors, at all.

If you think that skunked beer is just a rumour, get a 6-pack of Pilsner Urquell at the store. Chances are it'll be skunked (at least that's been my experience). If not, just leave one sitting on a windowsill for a week before you drink it. If you're wondering how you'll know if it's skunked, believe me, you'll know.

Green and clear glass doesn't protect from UV rays, but brown glass does, which is why brown glass is much preferred for us homebrew types.

salbast said:

OK. So it will affect the flavor if I refrigerate for a couple of weeks, take it out of the fridge and store it in a dark, cool place, then refrigerate again? I'm not just talking about skunkiness, I mean any off-flavors, at all.

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Nope...that happens all the time, both commercial and in many of our houses...we maybe move beer over to a friends, and it sits warm for awhile before going into the cooler...same difference.

Like I said, behind the scenes from brewery, through distributor to the back room of the beerstore, to the cooler, to our house with the groceries to when we get it into our fridge...

At the worse it can possibly affect long term storage of beer, NOT tastes of fresh product.

CaptainCoconut said:

If you think that skunked beer is just a rumour, get a 6-pack of Pilsner Urquell at the store. Chances are it'll be skunked (at least that's been my experience). If not, just leave one sitting on a windowsill for a week before you drink it. If you're wondering how you'll know if it's skunked, believe me, you'll know.

Green and clear glass doesn't protect from UV rays, but brown glass does, which is why brown glass is much preferred for us homebrew types.

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I believe you. But what about changes in temperatures. Does that cause off-flavors?

Revvy said:

Nope...that happens all the time, both commercial and in many of our houses...we maybe move beer over to a friends, and it sits warm for awhile before going into the cooler...same difference.

At the worse it can possibly affect long term storage of beer, NOT tastes of fresh product.

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Great! So I don't need another fridge just to store beer. I can just cool, put it in the basement then refrigerate a day before I'm ready to drink it. Thanks!

I believe you. But what about changes in temperatures. Does that cause off-flavors?

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Do it often enough (>10 cycles) and over a long enough period (~year) and the beer will take on sherry-like flavors. Eventually, it will oxidize.

salbast said:

I know the rule of thumb in these parts (which I'm following) is that we have to age the beer for at least 3 weeks before it reaches acceptable potential. Then you put it in the fridge for several days or so. Finally it's ready to be popped open and you're able to finally try out your creation. It tastes great so you decide to put half your batch in the fridge so it's ready for consumption. Now you decide that you need room for food and other items. So what happens if you take some beers out? I hear about the "skunked" rumors, but how would a commercial brewer be able to stock shelves with their beer with out proper refrigeration conditioning if this were actually true?
TL;DR: Would my beer have some off flavors if I refrigerate, take it back out and into room temperature, then refrigerate again?

Click to expand...

As an aside...if you are putting half your batch into the fridge at the 3 week mark, you are basically stopping the aging process for those beers by stabilizing them at a low temperature.

Instead, you may only want to put a 6-pack or so in at a time, so you can let the other bottles continue to age. One of the fun aspects of this hobby is finding out how the beer you've made changes over time.

david_42 said:

Do it often enough (>10 cycles) and over a long enough period (~year) and the beer will take on sherry-like flavors. Eventually, it will oxidize.

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I would probably do it once or twice for a set of beers.

broadbill said:

As an aside...if you are putting half your batch into the fridge at the 3 week mark, you are basically stopping the aging process for those beers by stabilizing them at a low temperature.

Instead, you may only want to put a 6-pack or so in at a time, so you can let the other bottles continue to age. One of the fun aspects of this hobby is finding out how the beer you've made changes over time.

Click to expand...

This is what I actually did with my stout. I wish I waited a lot longer, though. I only waited 2 weeks. I know.... BAD BAD BAD brewer!

It is certainly a rumor that a single hot cold cycle is particularly bad for beer.

If you want the beer flavor to be stable (a lot of people seem to like borderline stale beer to the point that you almost can't score well in competitions with fresh lagers), hot cold cycles are bad as is heat in general with the caveat that freezing the beer isn't good either. -1 C is probably the best storage condition, if you want stability. One way to test how stable beer is in a QA program is to take it through a number of hot cold cycles over a period of maybe a couple of weeks. The hot side of these cycles is over 100F. A single cycle from 40F to 70F and back is negligible.

As others have said, skunking should be used to describe lightstruck beer although it is quite common for people to use it casually to describe stale beer (which does not taste or smell remotely like a skunk in general).