There are a few ways the beer can go bad and skunking is one of them alongside the oxidation, heat exposure, and infection.
Skunked beer is a beer that’s been exposed to the light for too long and got light-struck due to the light sensitivity of hops. It doesn’t taste nor it smells as the real beer should, so knowing a few practices in advance will save you from experiencing this disaster.
In this article I’ll explain what causes skunked beer, what it means for you, and how not to let your beer ever become skunked.
Why is it called skunked beer?
It is called skunked beer because the chemical reaction called MBT (3-methyl-2-butene-1-thiol) responsible for the skunk effect in beer is chemically similar to the substance that skunks are known for. Moreover, the smell and the taste of a skunked beer is unpleasant and although it doesn’t truly exhibit the smell the skunk animals make it’s still bad enough.
How do you tell if a beer is skunked?
Skunked beer has a funky, flat wet taste accompanied with a smell of moldy cardboard or basement. This is the closet I could describe it, but once you experience it and compare with the fresh beer of the same type, you’ll know it doesn’t taste nor smell as it should.
Believe it or not, most people will have a hard time spotting a skunk beer from the first attempt, yet they will spot a flat or a warm beer immediately. The reason behind this is that the skunked beer tastes worse to what the same beer should taste when it’s properly preserved, but people drink bad beer anyways, so sometimes it’s difficult to make a call unless you know a thing or two about the beers.
That said, there are levels to how skunky the beer can become, early stages will be less noticeable then if the beer had time to get properly skunked. Anyone should be able to tell a skunked beer apart from the preserved, fresh one if they compare them one after the other, yet this rarely happen because if the batch is bad there’s no anchor point.
Will skunked beer make you sick?
Humans naturally associate unpleasant tastes and smells as something unhealthy and tend to avoid it. This is a nice survival trait that made us who we are today, but not everything that smells or tastes bad will make you sick.
For this reason you can drink skunked beer just like the oxygenated warm, or flat beer without worries that such beer will make you sick. However, there’s something that differs humans from animals, we actually demand a cold, crispy and pleasant beer and can’t settle for the less.
If you are worried, there’s no chance for harmful pathogens to appear in the beer just because it got skunked, so a homebrew beer is not dangerous for health even if it’s not perfect. The only difference is that the beer profile has changed and that’s it.
Imagine what beer must had been during the medieval ages or all the way to the 18th century before the standards for storing were regulated. I bet that the folk were happy if they could choose a beer instead of the water from a nearby river in which an animal decomposed a week before. The last thing on their mind was how carbonized the beer was or it’s flavor profile, you live the next day to experience a hangover? That’s good enough.
What causes a skunked beer?
Skunked beer is caused by hops exposure to the sunlight (UV) or other florescent artificial lights. The hops release alpha acids in the beer which in reaction with the light create unpleasant chemical reaction called MBT (3-methyl-2-butene-1-thiol) responsible for skunky taste and smell.
You see, the sunlight and artificial light might be the biggest enemy of beer because it doesn’t only attack with the light but sometimes also with the heat. The heat also has a deteriorating effect on hops, but this is especially highlighted when the oxidation is present.
It’s really hard to limit oxygen from entering beer after fermentation, so there will always be some oxygen which can deteriorate beer from inside when the bottle is exposed to the heat greater than room temperature. Why does this happen? Well, oxygen has a more impactful effect on higher temperature, so if you expect bad effects from oxidation they will occur faster out of the fridge.
However, let’s stay on the topic of skunked beer, this effect is caused only due to the light exposure and you should prevent it from happening by following a few simple practices like choosing a right bottle and storing in the dark place.
Why bottle choice matters
As you have noticed most beer is either sold in brown or in green colored bottles. There are exceptions such as Desperado and Corona which are not traditional beers but rather drinks on their own.
The color of a bottle acts as a membrane that reflects light back, yet no bottle will have 100% protection against the lights.
To put this into perspective, the visible wavelength is in the range of 380 to 740 nanometers and the range which can cause beer to go skunky is between 350 and 550 nanometers.
The emission of blue, green and purple colors has the worst effect on beer, so keep special attention not to introduce florescent lights, LED (around 400 nm) into your beer. On other hand, incandescent and halogen bulbs emit the light from a warmer range (yellow, orange, red) which has a less oppressive effect on the beer, but in the prolonged case will still leave a mark. The sunlight has the broad range of wavelength and the UV is especially dangerous, so don’t play with the sun.
So, brown bottles are the best and the green bottles follow. These are the only bottles you should use as a homebrewer to storage your bottles because even the minimum exposure can have a detrimental effect on the hops.
It’s enough for the hops to catch undesired light only for minutes to start going bad, so take this seriously, and avoid sun, LED or florescent lights while you should also minimize the exposure to incandescent and halogen light after the beer has finished fermenting.
If you need bottles for your homebrew choose the quality colored bottles that can sustain Co2 pressure.
Some beers are just sensitive
There are a few more important factors that play a big role in whether the beer goes skunky or not.
For instance, the darker the beer, the better protection it will have against the effects on undesired light exposure. Therefore, it’s harder for ales such as stouts and porters to go skunky, yet it’s not impossible.
Moreover, the beers will light hops portfolio will be less sensitive to the light then beers rich in hops.
Understanding the type of a beer is important because it’s necessary to protect some styles more than others and you don’t have room for mistakes. Additionally, some beers are supposed to be enjoyed fresh with least amount of conditioning, so understanding what certain ingredients ask for is super important.