It's a beer world after all!
The past decade has witnessed an explosion in the amount and variety of craft beer aged in wood, from hefty
sours to bourbon-barrel beauties. The techniques for barrel aging have remained the subject of oral history—
passed from brewer to brewer as a time-honored secret or learned the hard way through trial-and-error.

Wooden barrels have been the vessel of choice for beer fermentation and conditioning for more than two
millennia, with fully-enclosed barrels dating back to 800–900 BCE. Over that time, brewers have embraced a wide
variety of approaches to barrel use, coating them internally with brewer’s pitch to prevent the beer coming into
contact with the wood, or leaving them uncoated to impart wood flavor to the beer. The rise of industrial production
in the twentieth century led to the widespread use of steel in commercial breweries, largely due to its improved
capacity for cleanliness and sterilization. But for many breweries in Europe, the lineage of using wooden vessels to
ferment and age beer is a long and unbroken one.

So why are barrel-aged beers now in such vogue? Some credit Goose Island’s Bourbon County Stout, which
ushered in the most recent era of barrel aging in spirit barrels to impart flavors from liquor. The Chicago brewer
first released its hefty Russian imperial stout in 1992, and over the past two decades the beer has become one of
the most highly rated and regarded in the country. Others, such as Russian River’s Vinnie Cilurzo, began
experimenting with beers aged in wine barrels in the mid-to-late 90s, integrating his family’s winery experience with
his own passion for brewing. But the U.S. barrel-aging trend didn’t hit full steam until the early 2000s, as a general
cultural interest in artisanal products pushed more and more North American craft beer enthusiasts to seek out the
unique experience that these small-batch brews afforded.

One of the more interesting elements of the barrel-aging trend is the ecosystem that craft beer breweries have
built with their barrel suppliers. Many of these barrel-aging programs are a product of place, with Goose Island’s
(Chicago, Illinois) proximity to the bourbon-producing state of Kentucky facilitating a natural and symbiotic
relationship, while Deschutes Brewery’s proximity to Willamette valley wineries makes its barrel-aged beer a similar
part of the local terroir. Still others, like New Belgium Brewing, have approached wood-aged beer as a natural
extension of their mission to explore traditional European beer styles.

Barrel programs can be broadly characterized by their focus on either sour beer or non-sour beer that is typically
spirits-barrel focused, and many breweries produce both. Scale can vary, from local breweries with a handful of
barrels to full-scale production programs. By the time most brewers put beer into barrels, it has been fully
fermented in steel tanks, and the barrel is simply used to add character as the beer conditions. There are some
exceptions where brewers conduct primary fermentation in wooden tanks, but production breweries typically
demand more efficiency than that would allow.

Brewers using spirits barrels have a singular option for their beer conditioning—first-use (and sometimes second-
use) barrels that have contained spirits. For those brewing sour beers, there are more options—barrels or large
oak foeders—depending on whether the goal of the brewer is to extract flavor from the barrel or simply use the
wood vessel as the ideal environment for souring bacteria like Lactobacillus and Pediococcus and funky yeast
such as _Brettanomyces. _Foeders are ubiquitous among Belgian sour beer producers, and the wood capacity of
brewers like Rodenbach, with almost 300 foeders, dwarfs even the largest U.S. wood-aged brewer.

A decade ago, acquiring barrels was less challenging for a brewer interested in barrel aging. Distillers in the U.S.
often use barrels only a single time (sometimes forced to by law, in the case of bourbon), and for many years the
used barrels were seen as by-products without value. But the rapid growth of the barrel-aged craft beer market,
combined with the extended time that spirits like Kentucky bourbon typically spend in barrels, has led to more
market constriction.

Barrels are best when used immediately after a vintner or distiller empties them, and excessive processing or
sanitizing regimens can take valuable flavor out of the barrel or break down the wood itself.  he choice to keep a
barrel or retire it is generally made on a case-by-case basis.

Most brewers engaged in barrel aging have a limited number of “base beers” undergoing the aging process, and
the finished beers they release are blends of these base beers, often subject to additional conditioning with
additives such as fruit, cocoa nibs, or coffee either in barrels or in steel after the barrel-conditioning process.
There is no perfectly prescribed amount of time for a beer to spend in a barrel. It’s a subjective process that’s
based primarily in routine tasting and sensory analysis, but as a general rule barrel aging with spirits is much
faster than souring. Brewers know when the beer is ready by regularly tasting the contents of each barrel and
taking notes.


Hope you found this month's column of interest.  If you have any questions about beer or brewing
or just want to submit a word for me to discuss here just
e-mail it to me.

Thanks and Cheers!
Barrel Aging Beer
A new column by
Jack O'Reilly
Jack O'Reilly attended the
famous Siebel Institute/ World
Brewing Academy in Chicago.
I'm very excited to be part of the BeerNexus team.  I think my many years in the
beer business both as a brewer and manger will enable me to explain and
investigate many topics of interest for those who really love craft beer.
Hope you join me every month.  
More by Jack: #1, #2, #3, #4, #5, #6, #7, #8, #9, #10, #11, #12, #13, #14,
#15, #16, #17, #18, #19, #20, #21, #22, #23, #24, #25, #26, #27, #28, #29, #30,
#31, #32, #33, #34, #35, #36, #37
Techniques and insights
for the serious ceft beer
fan and home brewer