Barrel aging beers has become extremely popular practice among craft breweries and this has only been further popularised by the trend towards sour beers, which often require extended periods of aging, with the porous wood of barrels providing a great way to harbor bacteria and other souring microbes.
In a commercial setting, breweries will often purchase large, previously used barrels from distilleries or wineries. By large, we mean 53 gallon or 200 litres! By purchasing used barrels the brewery is hoping to impart some of the spirit or wine flavours into their beer, as well as the wood character of the barrel. Unused barrels can also be used for aging beer, giving the rich, wood character without the flavour of another alcohol.
In these size barrels there is a relatively small surface area of beer in contact with the wood meaning that barrel aging at this size can take months or even years. The beer in these barrels will often take on extremely rich, complex flavours which many homebrewers wish to recreate. In a smaller barrel the wood flavour will be imparted much more quickly and so samples should be taken more regularly.
If you are taking regular samples (and you should) then you need to be careful that you aren’t introducing too much oxygen into the beer. In a clean beer, oxygen will quickly stale the beer, giving it a damp paper or cardboard like taste that is unnapealing. In a sour beer, oxygen and acetobacter can quickly turn your beer to vinegar which you want to avoid
One trick that many homebrewers use is something known as a ‘vinnie’ nail. This is simply a nail inserted midway up the head of the barrel. Leaving the nail in plugs up the hole and prevents the loss of any beer but when you pull it out you get a small trickle of beer which you can run into a glass to take samples with. A small hole like this will also help to prevent oxygen getting into and ruining your beer.
What barrels to choose?
This depends on what you are trying to achieve. As previously stated, a larger barrel takes longer to impart flavour but you have the benefit of increased complexity and you loose less beer to evaporation. A smaller barrel imparts less complexity but the aging process is quicker and they require less beer to fill them.
Once you have decided on size you should look at the type of wood you use. Oak barrels are very common and easy to come across. Oak imparts caramel and vanilla flavours into your beer and is traditionally used for darker English or Scottish ales though it’s good to experiment with what’s available. The type of wood you use will affect the flavour of your finished beer and not all woods are suitable for using to age beer on.
Lastly you should consider the alcohol the barrel has been used for. Buying an unused barrel will give you fresh wood characteristics in your finished beer which can be an interesting layer. Aging your beer in barrels used to store spirits or wines will give you even more complexity. Whisky, brandy, sherry, tequila and wine are all common and will all impart great flavours into your beer.
What alternatives do I have to barrels?
For some homebrewers the size, cost or maintenance of a barrel is inhibitive and they require an alternative method of imparting wood flavours into their beers. Luckily, there are several options for brewers, including;
- Oak Chips – Oak chips are a great option. They are readily available from homebrew stores and come in a variety of different levels of toast, giving the brewer plenty of scope for imparting flavour. It is also very easy to soak them in your choice of spirit so you can still get that spirit barrel character. Due to the size of oak chips they provide a large surface area so will flavour your beer rapidly but some of the smaller shavings can be hard to filter out!
- Oak Spirals – These look like oak pegs that have been cut into spirals. They work really well because they provide a large surface area but are easier to get out of the fermenter than chips. They are a little bit harder to come by but work very well.
- Oak Cubes – A middle ground between chips and spirals, cubes are easier to separate from the beer post aging but offer less surface area so require more contact time with the beer.