Here at BeerTengoku Towers, like many other craft beer drinkers, we like to store our beers in our fridges, if there is space, or under the house – a nice small cellar that most Japanese houses have. The former is probably the easiest though with the amount in our collection, there is more beer than food in the fridge at times. The latter is not really a viable choice if you live in an apartment or flat, so we count ourselves lucky.
However, we can all agree that keeping the beers chilled helps keep them in their best condition for as long as possible. Of course, all beer will go off at some point, with some needing to be drunk as fresh as possible (NE-IPA!) while others will change with time and temperature – think of vintage beers, barleywines, imperial stouts, strong ales, and of course, lambics.
And this leads us into our soapbox – how has the store you bought your beer from been storing the beer? It seems like a simple idea but with the (slow) rise of craft beer in Japan, more and more stores are beginning to take notice, and starting to stock it. Yet, as the rise begins to creep up, how have the shop staff been trained, or how much do they understand about how craft beer should be stored? The two main factors that affect the flavour of a beer are temperature and light so let’s look at the first one.
How Does Temperature Affect Your Beer?
If you’ve been following us for a while, we’d like to think you’ve had an IPA or even a pale ale from time to time. You’ve cracked open that bottle that has been stored in a chiller for ages, and the flavours are muted. Where’s the bitterness? The flavours? Joe said this beer made his face scrunch up?! Why is it not happening to me?! And the beer is gone. The second time though, you let it warm up and then BOOM it’s a flavour explosion in your mouth and you’ve sworn yourself off IPAs.
Temperature greatly affects the profile of a beer. Without wanting to bring too much science into this, for every 10℃ increase in temperature, the chemical reaction rate doubles. So that basically means, if a beer is stored at 38℃ for one week, it tastes as old as beer stored at 21℃ for two months, or as old as beer stored at 4℃ for one year. The first might seem a little high – but remember in Japan, summers do hit 40℃ and over.¹
Take a look at your local supermarket and you’ll see row upon row of lagers – Asahi, Ebisu, Kirin, Sapporo et al – lined up on the shelf, warm and exposed. While the inside of the store might be a “cool” 26℃, how long have those beers on the shelf been there for? Take a look at the underside of the can and you might be in for a shock, especially with craft beer.
Malt-forward beers tend to hold up better than hop-forward beers, but another factor to look at is if the beer undergoes secondary fermentation in the bottle. An increase in temperature means the yeast inside that bottle is going to work harder, and carry on eating up the sugars in the beer. The beer’s flavour will change from perhaps one of a sweet, caramel malt forward, to a dry, bland, flat beer.If the beer is hop-forward, such as an IPA or pale ale, then the essential oils that contribute to the bitterness, aroma, and flavour, will break down over time. That American IPA with an IBU of 80 may become muted in comparison to something that is fresh or that has been stored properly. The sprightly hoppy bouquet turns to a papery, cardboard taste that doesn’t resemble anything the brewer’s PR has.
We’ve been to some shops that store their beers in fridges with doors – the perfect way though expensive as someone has to pay the electricity costs. Some places store their beers in open fridges – not as good as the chilling unit of the fridge has to work doubly hard to fight off the exterior heating. While other places have the beer out on shelves, exposed to the elements outside on the shop floor – a big warning bell for us and thus we tend to avoid buying beer from those places.
How Does Light Affect Your Beer?
The second factor is light; though to some degree this less significant than temperature. One of the reasons for this is the increase in canning. While the majority of breweries in Japan do use bottles, an increasing number are moving away from the brown bottles of old, to using aluminium cans, thus blocking out the light. However, we’re still a long way from having it as a majority due to the costs of importing aluminium, and sometimes steel, into Japan.
Glass bottles come in a variety of shapes and sizes, as well as colours, with that latter characteristic being the most important. The three main colours are colourless, green, and brown, with brown being the “best” for bottled beers. Clear bottles, while cheaper to manufacture, let the most UV light in – the same light that damages both your skin and also hops. While green bottles are slightly better than clear, they still let in too much UV light compared to brown bottles.
Why is UV light bad for your beer? It destroys the iso-alpha acids. The leftover chemicals hook up with sulfur-packed proteins, and produce a chemical compound that resembles a skunk’s defense spray. In other words: without protection, UV-exposed beer smells of skunk farts. Any beer that contains hops – pale ales, lagers, or IPAs for example – are prone to being “lightstruck” and thus going off. Brown bottles have the best resistance to allowing UV light to pass through; however, green was used for a long time as during WWII, brown glass was at a shortage. Of course, black bottles would be even better, but then you do want to see that there is enough beer in the bottle during the filling stage. Moreover, beer producers started to use green glass to denote their higher quality beer. This made it easier for consumers to tell which beers were from higher class European breweries and as such, the green bottle become a symbol of status.²
If you live in Japan, or have even visited Japan, you’ll have seen that neon lights are more common than vending machines on the street corner. Times are changing with the introduction of LED lights, but it’s a slow process. Neon light does produce UV light – not enough to harm a human – but enough to damage your beer that has been sitting on that shelf.
In the real world, where beers aren’t bombarded by lasers, light-struck beer is due to visible light between 400-500 nanometers in wavelength (the blue end of the spectrum) and ultraviolet light, which has a wavelength of less than 400 nm.³ Brown bottles block out light under 500 nm, and green bottles block light below 400 nm. So those neon lights might be lighting up the store and enabling you to see where you’re going, but if those bottles are out in clear packaging, then you can guarantee your beer is going to be damaged.
What to do?
We recommend the following steps when buying beer:
- How is that beer stored? Is out on the shelf open to temperature changes? Give it a miss and find something that is in the fridge. There is no guarantee that it will have been stored any differently before going into the fridge, but if you don’t see that same beer on the shelf, it will more than likely have been stored properly.
- Ask. Go ahead and ask the shop stuff how their beer supplies are stored. Are they in a chiller unit or out in a warehouse that is climate controlled? The warmer the beer is stored, the quicker it will be damaged.
- How is the beer packaged? Cans? Then follow the first step but you can be safe in the knowledge that your beer won’t be skunked. Anything other than a brown bottle and you’re playing a dangerous game. Yes, even that imperial stout that has been barrel-aged sitting on a shelf in a clear bottle is damaged.
This also extends to how you store your beer at home. If you know you’re not going to be drinking it immediately, then put it in the fridge to make sure the flavours don’t change too quickly or go off.
1 – https://www.storeitcold.com/beer-storage-temperature-affects-brew/
2 – http://www.oberk.com/packaging-crash-course/why-are-beer-bottles-brown
3 – https://www.livescience.com/33718-beer-skunks.html