Storing beer cold has a number of benefits, not the least of which is that it’s much more refreshing to crack a cold can of your favourite craft on a hot summer day. Sometimes the other benefits are overlooked however, and many of these reasons to keep your liquid gold in the ice box are even more important than the refreshment factor.
Keeping your beer in a refrigerator between 2° and 10°C keeps your beer in the best condition
possible, for a number of reasons that I will outline here.
Most of these reasons can be categorized under the umbrella of biochemical reactions, and are semi-permanent or permanent changes to your beer. Most of these changes are not exclusive to, but are more common in craft beer, this is mainly due to the fact that macro breweries like Budweiser pasteurize their beer. The benefit of doing so is that you effectively eliminate all microbiological life inside the product, increasing its shelf life and stability. The downsides are that pasteurization can eliminate some of the complexities in aroma and taste that we have all come to love in our local craft brews, and some people associate pasteurization with a slight “burnt sugar aroma”. To understand most of these issues, you’ll need a basic understanding of fermentation, which I’ll explain as simply the metabolic process that yeast use to create energy. To do this in the context of beer, use glucose (sugar) in wart (beer before it’s fermented) to create alcohol, carbon dioxide, as well as a large number of flavour compounds such as phenols, VDKs, esters, sulphur dioxide, acetaldehyde (fruity/apple aroma),etc.
Without further ado, here are some of the whats and whys of warm storing your craft beer:
1. Increased ABV: This is less prevalent in drier beers, because most of the sugar content has been used up by the yeast in the fermentation process, however, sweeter beer can experience fermentation in the can if the yeast has a comfortable environment. Lager yeasts are effective between 4°to 12°C, while ale yeasts work best between 13° to 21°C.
2. Increased pressure: When beer ferments, it creates pressure due to the fact that a byproduct of its metabolic process is CO2. Because of this, your cans can begin to feel hard, before bulging, and eventually failing and leaking your well deserved, after work beer all over your garage floor. This failure is usually located at the lid seam because it is the weakest point in the can, in the same way that your pants often rip at the seam when you squat too low. Yeast do not like high pressure so eventually they will die and stop fermenting your beer, but likely not before the pressure increases to a point that the constant volume (beer can), will have to expand to accommodate the pressure increase. The problem of increased pressure is compounded by Gay-Lussac's Law which states that the pressure of a given amount of gas held at constant volume is directly proportional to the Kelvin temperature (P = kT). So on top of the yeast creating more pressure by adding more CO2 to the can, storing your beer at 20°C instead of 2°C will increase the pressure by an additional ~6.5%.
3. Altered taste: This one is a deep dive for even seasoned blog post readers, and seeing as we're assuming most of you didn’t click this article with the intention of getting a degree in biochemistry, or accreditation as a master brewer, we'll keep things brief. For those rabbit hole crawlers for whom we am unable to satiate the desire for infinite knowledge, click the link provided to start on. In the metabolic reaction called fermentation, there are a plethora of byproducts. A large number of these create aromas, or alter the body of the beer. Many of these products are desirable in some beer, but not in others. A number of these byproducts can combine with other elements present in the beer to create further byproducts. When using yeast, breweries attempt to account for how much of these compounds will be in the finished product, but when yeast is allowed to continue to ferment past the expected amount, some of the desired aromas and flavours may be covered up by less desirable ones. For those adrenaline junkies who get their fix via spelunking in caves of knowledge, here is a good place to start.
4. Bacterial or Wild yeast propagation: This could also be a subcategory of the previous issue, as it is similar in nature. There are a number of bacteria or wild yeast strains that commonly make their way into beer. None of which are harmful to the drinker, but in their metabolic processes, they alter the final product, and 99% of the time it is in an undesirable way.
5. Yeast sludge at the bottom of the can: You may have had a bottle of beer that was “bottle conditioned” which essentially means that it was fermented in the bottle. Because of this, you’ll likely have experienced the sludge at the bottom of the bottle that can sometimes make your last few sips or last glass a bit cloudier than the rest. This is nothing to worry about, as it is just yeast that has propagated during the fermentation process and has settled at the bottom. There’s always yeast in beer, but it is usually in small amounts that are in suspension, and it actually can provide some of the pleasant characters in your beer. Sometimes however, this is not desired in a packaged beer, and can take away from some of the more “clean” beers.
There are other reasons to keep your beer at the appropriate temperature, but these are the ones you’ll notice the most if you forget to give your brewski a loving home.