Beer on Wood

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Being nostalgic beings, brewers look at beer’s rich history as inspiration for their next beer or as a guidelines for their wildly imaginative brews. More and more brewers are reverting to traditional technology and are eagerly exploring the possible interactions between maturing beer, permeable wood, and microorganisms. The interplay between wood and beer is very complex. Today, we are investigating the two main effects of oak on beers; namely barrel-aging using bourbon barrels and barrel-fermenting with wine barrels.

Barrel-aging.

By law, bourbons must be aged in new American barrels which are heavily charred to depart smoky flavors. The result is a charred oak barrel permeated with bourbon. The most popular beer styles using the bourbon barrel-aging process are dark, malt-accented, and reasonably muscular beers that are able to stand up to the potent influence of bourbon.

When a brewer refers to barrel-aging, they’re talking about beers that have been fully fermented and attenuated ‘clean’ (no live bacteria) beer. You could drink the beer as-is but is placed in bourbon barrels to add flavor to the beer or to smooth out the alcohol in a beer, not to act as a fermentation vessel. Many would consider this the 5th ingredients in beer. The beer could age in the barrel up to 1 year or more and is usually blended with other barrels for the best and balanced taste.

At Blue Supreme, we have a few barrel-aged beers. La Renaissance by De Dochter van de Korenaar, is a barrel-aged IPA. De Dochter, the brewer, used all English malt and hops and matured the beer in Puligny Montrachet barrels. The dry white Burgundy’s acidity and earthiness complements well with the beers bitterness. Before bottling, its further dry hopped to exude a crispy, fresh hop flavor, resulting in a complex beer with wine like characteristics and herbal and citric hop aromas. The brewery wanted to explore the true taste of original IPA that travelled from England to colonial India. Such beers was held in barrels and oak would play a part in its taste.

Barrel-fermentation.

Wines have a more mellow flavor than spirits, so wine oak barrels allow the beer to shine. Wine is also low enough in alcohol that bugs such as Brettanomyces and Lactobacillus can survive within the staves. Although Brettanomyces growth is one of the reasons that winemakers have to retire their barrels after a period of time, brewers are able to use these barrels exclusively for sour and wild ales—which is, beers fermented with wild yeast and bacteria other than Saccharomyces, the “clean” brewer’s yeast.

But , what is fermentation? Beer fermentation is when the yeast and bacteria convert grain-derived starches and sugars into alcohol, CO2, and other flavorful and aromatic compounds such as acids. Different yeasts and bacterias perform this task differently, and the conditions surrounding these organisms would significantly affect the end product.

Brewers would brew a base beer in stainless steel tanks first then transfer the beer it into the wine barrels. The yeast and bacteria dwelling on the walls of the staves will further ferment the beer, creating depth and flavor. These beers are most commonly described as refermented in the barrel or mixed fermented or wild ales. Additionally, brewers can add wort to a barrel or other wooden vessels and allow naturally present bacteria and yeast to ferment it, such as Belgium lambic producers. This beer would are described as a lambic-style or spontaneously fermented beer.

All our beers under the sour and funky section are a result of mixed fermentation by wild yeast and bacteria in wooden barrels. Such fermentation creates nuanced, vinous and balanced acidic beers. To beat the hot Hong Kong weather, we recommend the Cuvee Sofiee Rabarber by Brouwerij Alvinne.  The a blond sour beer fermented with rhubarb in barrels, resulting in wine like characters of dry fruitiness and refreshing acidity.

 

 

 

Ted Lai