I've been asked this question a couple of times lately, so today we'll tackle the issue head on: Why do Americans drink their beer at refrigerator temperatures; or, in the alternative, How can Europeans drink warm beer?
We constantly hear: "cold filtered", "ice cold mountain water", "serve chilled", "have an ice cold brew", "ice cold beer here!", "man, I could go for a frosty one." We see "cold activated bottles", Budweiser and MGD are served in frosty mugs. We, Americans, have come to expect our beer to be cold. In the summer we reach for an ice cold beer when we come in from the hot outdoors. We think beer has gone bad if it warms up to room temperature. We get concerned that beer will be skunked if it is moved from a cold place, to a warm place, back to a cold place. But, what we find is that this fear of warm beer is almost entirely driven by those that produce American lagers (i.e., Budweiser, Miller, Coors, etc.).
Since 90%+ of the beer that we drink in this country is produced by these macro breweries, and is, in fact, American Lagers, we assume that all beer should be sold at refrigerator temperatures. This impression is further reinforced by retailers that keep their beer in walk-in refrigerators or other refrigerated areas, even retailers that should know better. To some extent this is a chicken and egg situation; consumers won't buy beer that isn't in a cooler, so retailers keep beer in coolers, so consumers think that all beer needs to be in coolers and won't buy beer that isn't in a cooler.
And, as you will see, some beer, like American Lagers, should be consumed at refrigerator temperatures. But, not all beer should. And, in fact, some beers should not.
So, let's look at what effect refrigeration has on the final product that we call beer. Note: we are not talking about fermentation temperatures. To some extent we will talk about conditioning, which is a form of fermentation, but we are talking about storage and consumption of beer here.
Some companies, like those interested in selling keg systems for American Lagers, want you to believe that the ideal storage and serving temperature is 38 degrees F. Their argument is essentially that beer that is warmer than 38 will foam unnecessarily (lost profits!), and beer that is too cold will not foam enough (lost profits!). But, what this article fails to mention is that these theories only apply to American Lagers that are carbonated like American Lagers. What if the beer on tap is a barley wine, a style that is less carbonated than an American Lager? What if the beer on tap is a stout, or a doppelbock, or an IPA? Each of these styles requires different carbonation, different pressure settings to dispense properly, and different temperatures.
Let's start, then, at the bottom. Why are American Lagers best served at 38 degrees? The primary reason is carbonation. American Lagers are force-carbonated by carbon dioxide (CO2). What does that mean? Well, beer by its nature is flat; we carbonate beer to give bubbles. Why do we want bubbles? Because, circularly, we don't want flat beer. In other words, the bubbles provide respite from flavor and body. So, there is something about the flavor and body that we find undesirable. In this case, the American Lager, a very light beer as it is, its very purpose is to be a session beer: something that we can drink in (significant) quantities. Something that is refreshing. Well, bubbles make the beer taste even lighter, and we feel like we can drink more of it.
CO2 is a natural byproduct of the fermentation process. Before pasteurization and force-carbonation, and even in some styles today, beer was carbonated in the bottle or keg by providing some tiny amount of sugar for the tiny amount yeast that is still active to feed on; the beer continued to ferment in the bottle or keg. During normal fermentation this CO2 is vented away from the container. In the bottle or keg though, the CO2 is kept in the bottle. Where, where does the CO2 go? If there is headspace in the container, the CO2 goes into the headspace and then is vented out when the container is opened. If there is more CO2 than there is headspace, the CO2 is absorbed back into the beer. When the beer is opened and poured, the CO2 escapes the beer in the form of bubbles.
For pasteurized beer there is no active yeast remaining, so if we want carbonation, we have to introduce CO2 into the beer since we can't generate it. Well, the more CO2 we can get into the beer before the beer is "saturated", the more carbonated the beer will be, the more bubbles (and, generally, foam) we will get. It turns out that the colder the liquid is the more CO2 it can absorb before it becomes saturated. So, beer that we force-carbonate and that we desire to be highly carbonated, is cooled to get the right amount of CO2 into it.
What does all of that mean? Beers that are highly carbonated should be served cold (chilled) to maintain maximum carbonation. Conversely, beers that are not highly carbonated do not need to be served cold. Wine is the same way, wines that are carbonated, typically white wines and sparkling wines, are served cold (chilled), while wines that are not carbonated (typically reds) can be served at room temperatures.
But, cold not only affects carbonation, it affects aroma and taste.
In the first place aroma is completely suppressed at low temperatures. The volatile compounds in malts and hops, essential oils that are soluble in alcohol, which provide aroma, are not released at low temperatures. It is only by warming up that these essential oils are released from the alcohol in sufficient quantity to be detected by our noses. So, beers that have very little aroma component, low hopped beers like American Lagers, can be served cold; beer for which aroma is a desirable attribute should not be served cold.
The other thing that happens when foods, like beer, are cold is that taste buds are "frozen", thus narrowing the range of tastes that can be perceived. On a technical level, what actually happens is that the bodily function (gene/protein combination) primarily responsible for transmitting taste (a gene called TRPM5) behaves differently at cold temperatures than at hot temperatures. In particular, though it is true for almost all flavors, bitterness in particular is transmitted more intensely at warmer temperatures. This means that any beer for which flavor, such as bitterness from hops, is a desirable component should not be served cold. Interestingly, it also means that super-hoppy beers should not be served too warm or it will be overly bitter.
The suppression of aroma and flavor is a distinct advantage for American Lagers. Brewed with low-quality six-row barley* and a significant proportion of corn or rice, these beers are essentially made using animal feed – stuff that doesn't taste particularly good. The producers don't want you to taste their product. So, they highly carbonate it and encourage it to be consumed as cold as possible. It's also why when that Budweiser or MGD or PBR warms up it tastes terrible - it's carbonation is gone and the true flavors are fully revealed.
But that doesn't mean all beer needs to be served cold; only beer that you don't wish, or need, to smell or taste. Lighter beers like pilsners and light lagers can be served cold and are very refreshing. Beers like weisse beers (wheat beers), typically use other methods to 'overpower' the cold suppressing effects and can be consumed cold (the yeasts that these beers use provide a fruitiness that overpowers the cold). Even beer that is best served cold should not taste terrible when warm though - you can verify with some well-made pilsners or weisses; let them warm up and they are still eminently drinkable.
But most other beer should be served at least at 50 degrees F to encourage aroma and prevent the suppression of the flavors.
What I find most interesting, is that beer, as its temperature chages, changes itself. For example, when the beer is cold we can't smell it, and thus cannot rely on that component to inform our tastes. Our taste buds are frozen to certain flavors, but still allow others. As the beer warms up, the aromas are released adding a new component to the flavor, and our taste buds are able to detect a wider range of flavors revealing some flavors that were not detectable earlier.
This has gone on long enough. On Wednesday we'll review a beer that is completely different at cold, tap, temperatures (remember, 38 degrees?) and warmer room temperatures.
*I do not mean to denigrate six-row barley implicitly; I love six-row barley beers like biere de garde; but it does provide a huskier, less 'refined' barley flavor that some find undesirable.