In the brewing process, the so-called “barrel” refers to the process of placing the beer in oak barrels to continue fermentation and aging. The first wooden barrels were invented by the English, who made beer into
a large number of barrels to allow for secondary fermentation and to have more flavor in the aging process. The Belgians later learned from the English barrels and brewed the first Landes Red Ale through secondary fermentation, which had a very strong flavor and low acidity. Since then, the Belgians have taken to producing large quantities of sour beer barrels for secondary fermentation.
And since the 1970s, the craft brewery movement has grown like wildfire, and the old brewing technique of “kegging” has been updated. Craft breweries, represented by the United States, have made a push for “barrels”, and especially in the last 10 years the “barrel” trend has once again hit almost every craft brewery, from sour beers to strong beers, even to wheat beers and IPAs, you can find versions of almost every beer model that has a barrel, and some beers have even been barreled more than once.
Point 1: Take advantage of the barrel. Wooden barrels are one of the most important ingredients for many beers, such as whiskey, bourbon, wine, brandy, dark rum, sherry, porter, etc. Wooden barrels often have a rich flavor profile. There are many types of barrels used, but the most widely used is oak (Quercus robur). In the modern craft beer “barrel” process, the most frequently used barrels are the “used barrels” left over from brewing various brews. These barrels often have the flavors of other beers in them and will absorb many of these flavors, giving the beer itself a richer, more intense flavor, such as aging in bourbon barrels to receive a distinct vanilla aroma and hints of toasted coconut oil, and aging in brandy or wine barrels to receive some fruit aromas and tannins. Some beers aged in hard barrels also generally increase in alcohol, but also bring out some warm alcoholic flavors. The most used “used barrels” in beer barrels today are American bourbon barrels – that’s because American bourbon barrels have a strong taste, and partly because American brewing uses only new bourbon barrels, so there is a rich source of used barrels.
In addition to bourbon barrels and beer barrels, there are almost any barrel used to age beer, such as scotch barrels, brandy barrels, wine barrels, and more. For example, the Bourbon County Brand Stout from Goose Island was the first beer to go through thick oak barrels.
Second: Barrel-aged beers utilize a secondary fermentation of microorganisms in the barrel.
Most of these beers are sour beers. Since some barrels (especially wine barrels) can have many microorganisms left in them, such as bacteria and wild yeasts, many sour beers are brewed using these organisms to produce sourness (acetic or lactic acid) and other special flavors (such as using the wild yeast Brettanomyces to produce some
moldy sweetness – a foul taste). Of all the types of sour beers, perhaps only the two German sours, Berliner Weisse and gose, do not need to be barreled, while almost all other sours have to be brewed in barrels to ensure sourness and musty aromas, and some fruity sours have to be barreled twice – the first time to produce the sourness, and the second time to mix with fruit to bring the sourness, mustiness and fruitiness into harmony.