Question- Beer on tap in Summer time

My understanding is that skunking happens with direct light, particularly sunlight, and can occur in bright sunlight within minutes. That's why I always LMAO when I see the Corona commercials where folks are enjoying a sunny day at the beach where they are skunking their clear-bottled beer in a tub of ice. Ice won't prevent skunking, but might slow it. Good thing Corona is available in cans now.

Anyway - what you're seeing isn't skunking unless you're taking your beer out on the patio and sipping it in the sun. What you are likely observing is beers like IPAs pushing or exceeding their drink-by date. Winter beers tend towards stouts and porters which keep well, but summer tends towards IPAs and other lighter beers that don't keep as well.

If you are taking your beers outside, keep them out of direct sunlight where they can skunk in under 15 minutes. Same goes for bottled beer at home - either keep it in the fridge, or in a closet or cellar where there is no direct sunlight or constant home lighting. I used to keep my beer in the kitchen where it would catch late day sunlight - bad move. Colored bottles are better than clear, but can still skunk.

 

Well, first thing, it isn't skunked in the keg since that is only going to happen if the beer is exposed to light. However if you are having more beers outdoors on the patio and the glass is exposed to the sun for a while that's when it may be getting skunked. Sit in the shade or keep the beer in the shade all the time.

 

After thought.

Check out this video.

 

Can't say I'm an expert on the DC bar scene, but I have noticed what I assumed were dirty lines more there than any place else. A number of places also use nasty, chemical cleaners on glasses without properly rinsing them off. Not saying either of those are what you experienced, but maybe?

 

Wow - that was interesting to hear how bad it can get, and the chemistry behind it. I recall reading about another test where someone timed it and it took a surprisingly few minutes to skunk a beer, like 10 minutes. I don't suppose you'd be able to talk a taproom into using brown glasses for those heading out to their patio - since folks wan't to see the beer.

 

My guess is that you are noticing some effects of beer staling vs. skunking per se.

You specifically mentioned that this 'effect' is a summertime phenomenon. What is different between the summer and other times of the year? You got it: heat. The two big enemies of beer are oxygen (i.e., oxidation) and temperature (heat). When a package of beer is stored warm/hot this accelerates the chemistry of beer staling. As regards a well tended bar, draft beer (kegs) should always be stored cold. Maybe some of the "dive bars" you mentioned are not conscientious about properly storing/handling their beer so they are going stale more quickly in the summertime? In comparison you are not noticing this at the 'good' bars since they treat their beer well.

Cheers!

 

One advantage of living in a latitude such as mine is that leaving beer out in the sun does not spoil it. In fact the only skunked beer I have tasted was deliberately doped on a tasting course. It was not very nice.

 

Take any beer outside and you will notice the skunking taking place quickly. Stay inside and non-issue!

 

I doubt even being out in the sunlight is the issue for beer in the glass. Assuming the beer being served is cold then the beer isn't hitting a temperature that would probably cause the beer to go stale quicker than the keg is being turned over. The last time I looked at the Arrhenius equation graph it takes around 90 days for beer at 68 degrees F to go stale (I don't claim to be an expert on the graph so others more experienced with this may disagree in my assessment). So I doubt that beer that has been tapped is stored at a high enough temperature in the summer to make the biggest contribution to the taste issue. Perhaps the beer is stored at too high of a temperature before being tapped, either on premise or prior to delivery. After tapping I'd guess the storage temperature is adequate because lots of people are more annoyed by warm beer than off flavors in their beer. You can serve crappy cold beer but you can't serve warm beer to the average patron in summer.

I'd tend to bet the issue is more with the cleanliness of the bar with regards to their taplines, faucets, etc.. Summer is usually a busier time for bars, especially the outdoor patios mentioned. That business probably accounts for less attention to cleaning schedules which means more buildup of bacteria and such across all aspects of the bar. The warm weather will also mean that the bacteria growth is going to be at a higher rate which probably affects the taste of the beer. Personally I'd stay away from any place in any weather that serves beer that doesn't taste right, it probably means they are not as clean as you'd want them to be. That's at least my 2 cents on the issue.

 

It is my understanding that skunking of the beer is a chemical reaction between ultraviolet rays in sunlight and hop oils which begins within seconds of exposure irrespective of the beer temperature. I don't have the cites at hand but a search here on skunking should turn up studies that show beer in a clear glass exposed to direct sunlight can be completely skunked in less than two minutes.

 

Sorry if I wasn't clear, I should have started a second paragraph. Skunking would only have occurred if it was in the sun. I doubt that skunking is causing the off tastes since he has the issue in both outdoor patios and indoor dive bars. My first sentence was addressing the idea of skunking. After that I am just discussing what I would assume is causing any off flavors which is not skunking but likely attributed to bacteria or yeast growth in not well cleaned bar equipment.

So basically the three options are:
1. Skunking, only due to sunlight so unlikely
2. Stale beer caused by beer not kept at proper temperature. I believe unlikely post tapping but potentially could have occurred during storage or delivery
3. Bacteria, yeast, etc. due to poor cleaning and exacerbated by warm temperatures. Most likely source of off tastes IMHO.

 

I see, I'm good at grabbing a first impression then jumping the gun.

 

I concur.

 

Yep, I've had it happen instantly. You can order your beer inside at the bar and take a sniff and a sip which are perfect then walk outside into the sun and smell the beer and it's instantly skunked.

 

Your latitude and temperature should have little to do with it. You still have UV light and it will skunk unless the beers are brewed to reduce latent hop oils.

 

My own experience in the UK is much the same as Marquis describes.

Notice that the UV index for your area of the country is often greater than 8, and for tommorw it is expected to be close to about 8.

http://uv.willyweather.com/sd/minnehaha-county/sioux-falls.html

Meanwhile the UV index for the Nottingham area of the UK where Marquis is located are significantly lower. The forecast there for tommow is about 5. (Note that the UV index scale is not linear.)

The angles of light from the sun are significantly different. (e.g., to get the same amount of UV in Europe that we have here in Philly you have to go to Rome. Much further north and the index begins to drop.

 

I truly love your latitude, but being blessed by the Gulf Stream has never been a negative effect in your neck of the woods. It is a beautiful confluence. Good old Ben Franklin was somewhat responsible for likely first describing "some" prevailing ocean currents. It isn't a crowded literature, but reading about the oceans from deep in history always remains illuminating.

 

I like your reasoning but you forgot two other options:

4. The connections between the beers, locations, and season are actually all a coincidence.

5. There's nothing actually wrong with the beers.

Neither of those are meant as a knock to the OP in the slightest - I'd certainly include either possibility if it was my question too.

 

@marquis BTW, note that without special,training such as you had many could have some of the off flavor,without realizing what it is. Or may.not be bothered by low amounts of the chemicals involved.