Beer and wood have a long history together. Wood has played a part in beer making since the very beginning, as a source of fire, flavor and as a vessel. For hundreds of years, wood provided the heat to kiln malt, which imparted a smoky flavor to almost all beers. Wooden barrels also provided an easy way to transport and serve beer.

In the modern world, wood is no longer needed. Stainless steel now provides the material for tanks for fermenting and kegs for serving. Breweries are powered by steam or gas and malt is kilned with indirect heat that imparts no smoky flavors.

But we can still find beers influenced by wood, and breweries that use wood to impart unique flavors. In a world dominated by “clean beers” — fermented in stainless steel that adds nothing to the taste — these wood-influenced beers are a special treat.

The old way: Before metal tanks, most beer was primarily fermented and aged in large wooden vats. This process is still followed at the 900-year-old Tra­quair House in Scotland, originally a hunting lodge for kings and queens. In the early 1960s, the family discovered a brewery under the chapel dating to the 1700s.

The brewery was restored and the original equipment put back to use, including 200-year-old Russian memel oak vats. The beer is allowed to ferment in these vats before further aging and bottling. The wood is so old that most of the oak’s compounds have been leached out, and it no longer imparts a strong taste. Instead, it provides a smooth, rounded flavor accentuated by a slightly sweet maltiness. Traquair House Ale is a strong, 7.2% Scottish ale with notes of dried figs, plums, vanilla and toasted sweet bread.

THE LAMBIC WAY

This historic method, developed in the Zenne river valley surrounding Brussels, uses wooden barrels and vats to produce sharp, acidic flavors. Lambic is a beer of spontaneous fermentation, relying on natural yeast and bacteria in the air to inoculate the beer. No yeast is added. Once brewed, lambics are cooled in large shallow pans called koelschips (coolships) in rooms that allow outside air to flow in and cool the wort (unfermented beer). Once fermentation begins the beer is transferred into wooden barrels or large wooden tanks called foeders.

Drie Fonteinen is one of the few remaining lambic producers, with hundreds of foeders once used to age Italian wine and French cognac. The wood in these barrels contains billions of yeast and bacterial strains that ferment and age the beer, imparting flavors from tart and acidic, like vinegar, to soft, ripe peach. Drie Fonteinen’s Armand & Gaston Geuze is a blend of 1-, 2- and 3-year-old lambics from various barrels and foeders. The highly effervescent beer is aggressively acidic up front, with tart lemon and key lime notes, but quickly transitions to flavors of white peaches, nectarines and freshly cut grass.

THE NEW WAY

Over the past 30 years, craft breweries have discovered that wooden barrels not yet drained of flavor can add incredible notes to beer. Many beers are now aged in used spirits and wine barrels that are brimming with flavors, not only of the previous liquor stored in them, but also of the wood of the barrels.

At Big Island Brewhaus, head brewer Tom Kerns ages his Golden Sabbath Belgian-style golden ale in American oak barrels that once held chardonnay and bourbon. These freshly emptied barrels still bear strong notes of vanilla, coconut, marzipan and cinnamon. After up to eight months of aging, Kerns carefully blends the contents of the barrels to achieve a unique and robust flavor profile that showcases the oak upfront on the nose. In this beer you can experience the flavors that the wood itself contributes.

Tim Golden, a certified cicerone, shares his obsession with all things craft beer on the third week of each month. He is part owner of Village Bottle Shop in Kakaako.