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General Category => General Homebrew Discussion => Topic started by: theoman on December 05, 2010, 07:11:33 AM

Title: How quickly to skunk?
Post by: theoman on December 05, 2010, 07:11:33 AM
I just got up this morning and noticed that I left the florescent light in the cellar on last night. I'm usually fairly careful about covering my beers, even down there. I was less careful with this latest brew. Most are in brown bottles, but I do have some in green 75 cl bottles that I was planning to give away as gifts. Should I start shopping for other gifts?
Title: Re: How quickly to skunk?
Post by: punatic on December 05, 2010, 10:07:11 AM
Relax, don't worry, have (and give) a homebrew!

They are fine.  Gift away.
Title: Re: How quickly to skunk?
Post by: hopfenundmalz on December 05, 2010, 01:05:52 PM
If you want to, do some quality control.  Drink one and see if it is skunked.  I think Punatic is correct, it will be OK.
Title: Re: How quickly to skunk?
Post by: Malticulous on December 05, 2010, 03:51:15 PM
I intentionally left a few lagers in green 12 oz bottles in direct sunlight for 10 minutes. That was enough.

750ml under florescent light? Who knows.
Title: Re: How quickly to skunk?
Post by: MDixon on December 05, 2010, 04:03:17 PM
Supposedly it is an instantaneous reaction. Personally, I'm not convinced. I tend to believe (without proof), the reactions are occurring, but the breaking point between perceivable levels of mercaptans and imperceptible levels is the point which seems instantaneous. Why do I think this...beers can skunk in green bottles sitting in a cooler case, one day you purchase a sixer of beer and everything is fine, a few days later another sixer from the same cooler is skunk city. That makes me think prolonged exposure builds the byproducts of the reaction until they are perceivable. Sitting a glass of beer in direct sunlight can seem to drive the reaction extremely quickly to a perceivable level of mercaptans.
Title: Re: How quickly to skunk?
Post by: SiameseMoose on December 06, 2010, 03:48:48 PM
I have done some professional lab research on this topic. (Sorry, I can't reveal who I was working for, or who was paying for it, but I can talk about the results. Don't ask.) I will add the caveat that we didn't study flourescent light, just sunlight. We could not find a predictable time threshold for the reaction. It is definitely based on the intensity of the light source, as well as the temperature. On a bright day at summer-time A/C room temperature, skunking could happen effectively instantaneously, but more often it takes an hour or more. Every beer (in a green bottle, that is) was skunked to flavor thresholds in less than two hours. They were skunked to instrumentation thresholds in minutes. Brown bottles doubled the time period. Double a few minutes is only a few more minutes. A bottle taken out of the refrigerator did not exceed flavor thresholds unless it was exposed long enough to warm to room temperature. We also only looked at one mass market lager, one I would not call bitter. I don't know the effect we would get with differing bitterness levels.
Title: Re: How quickly to skunk?
Post by: 1vertical on December 06, 2010, 04:14:14 PM
F.Y.I. we ran a test earlier this year and set an APA out in a clear glass in full sunlight
in less than 10 minutes it had skunked...

Skunking Does NOT take very long under those conditions
Title: Re: How quickly to skunk?
Post by: denny on December 06, 2010, 04:16:04 PM
I have skunked a very hoppy beer in about 5 min. in a clear glass in strong direct sunlight.
Title: Re: How quickly to skunk?
Post by: jeffy on December 06, 2010, 06:59:43 PM
It really doesn't even take that long in my experience, but I'm in a warmer climate if that's part of the equation.
Title: Re: How quickly to skunk?
Post by: James Lorden on December 06, 2010, 07:08:47 PM
In the summer while grilling outsidem, I have had beers that I swear skunked while I was drinking them!
Title: Re: How quickly to skunk?
Post by: hopfenundmalz on December 06, 2010, 08:14:35 PM
I have had IPAs skunk in less than 3 minutes sitting in a clear glass under direct sunlight on my back deck.  It was one of those rare clear days in Michigan.

Title: Re: How quickly to skunk?
Post by: richardt on December 06, 2010, 09:37:02 PM
Elevated temps (e.g., during unrefrigerated transport on cargo containers/cargo ships) may cause more than one flaw in the green bottled import beer to occur.  Sometimes when I crack open one of those green bottle imports (e.g., Heineken), I sense there's skunking as well as some oxidation.  Blech!
Title: Re: How quickly to skunk?
Post by: hopfenundmalz on December 06, 2010, 10:07:18 PM
Most lagers from the Continent have some staling.  If you smell honey like aromas, that is oxidation.  I don't buy as many German Pilsners as I used to.  But I can make some fresh ones!
Title: Re: How quickly to skunk?
Post by: Thirsty_Monk on December 06, 2010, 10:55:05 PM
Very interesting topic.
Thank you.
Title: Re: How quickly to skunk?
Post by: James Lorden on December 07, 2010, 12:20:35 AM
Most lagers from the Continent have some staling.  If you smell honey like aromas, that is oxidation.  I don't buy as many German Pilsners as I used to.  But I can make some fresh ones!

Bitburger in a can, it's a life saver!
Title: Re: How quickly to skunk?
Post by: hopfenundmalz on December 07, 2010, 01:09:55 AM
Most lagers from the Continent have some staling.  If you smell honey like aromas, that is oxidation.  I don't buy as many German Pilsners as I used to.  But I can make some fresh ones!

Bitburger in a can, it's a life saver!

If you like Bitburger.   ;)

The local Pizza/Italian place had 4 beers on draft when I lived in Germany.  Koenig, Kostritzer, Warsteiner, and Bitburger.  That was my order of preference. 
Title: Re: How quickly to skunk?
Post by: speed on December 07, 2010, 02:33:52 AM
i left a homebrew in the sun for a few minutes and was surprised how fast it skunked.
Title: Re: How quickly to skunk?
Post by: theoman on December 07, 2010, 01:12:37 PM
Definitely some interesting answers. For my situation, I've decided not to worry about it. Fortunately, it turns out that my green bottles are closed in a box. I'm smarter than I thought. I have some commercial beers as well as some homebrew in brown bottles that were exposed. I can't imagine the weak florescent light had much effect on the brown bottles. If it did, there weren't many.

Somebody more ambitious than I should do an experiment with florescent lighting.
Title: Re: How quickly to skunk?
Post by: uthristy on December 07, 2010, 01:35:18 PM
All sounds about right, as I can walk from the backdoor to the pool (25 ft) and the beer is skunked.
Title: Re: How quickly to skunk?
Post by: punatic on December 07, 2010, 04:05:23 PM
All sounds about right, as I can walk from the backdoor to the pool (25 ft) and the beer is skunked.

If you quit leaving the cat food outside the skunks won't be attracted.  ::)