oak alternatives. With the oak barrel being the long-established vessel of choice for the aging of spirits, wine, and beer, the twenty-first-century global explosion in the production of these beverages has created recent barrel shortages. Spirits producers have looked for other choices as occasional scarcity and increasing price pressure have given impetus to finding alternate methods to traditional oak aging.
Carya ovata) and sugar maple (Acer saccharum), this is not a new practice. Among the woods that have been used are those related to oak, such as chestnut (Castanea sativa), formerly used for barrels and by some distillers in Cognac and still occasionally used in Italy for grappa vats, and, in Chile, rauli wood (Nothofagus alpina), a species of southern beech, still used for the large vats in which some pisco is matured. See pisco.Other hardwoods have been used as well, both for barrels and for vats. Batavia arrack, a spirit that rivals cognac in antiquity, was traditionally shipped from Java to the Netherlands in 600-liter leggers made of teak (Tectona grandis), which proved to be strongly extractive over the many months the spirit spent in transit. To this day, teak is used for the large vats the spirit matures in. In Sri Lanka, palm arrack rests in vats of halmilla wood (Berrya cordifolia). See arrack, Batavia.
Nowhere, however, goes farther into non-oak woods for aging than Brazil, which uses a long list of woods of varying degrees of reactivity, from the highly reactive amburana (Amburana cearensis) to the fairly neutral ipê roxo (Tabebuia heptaphylla), for aging cachaça, chiefly in vats. Of all the alternative woods used for aging, some of the Brazilian ones move the farthest away from oak in their effect on spirits. See cachaça.
For various reasons, however, including cost, supply and—in the case of hickory—excessive porousness, these woods are impractical for anything more than local use. Sticking with oak itself, however, there are numerous alternatives to the standard 200- or 250-liter barrel; included among them are oak chips, but also smaller-sized and miniature barrels, full inner staves (new staves placed inside barrels), new barrel heads, and oak powder, or pulverized oak. These are legal for most spirit production, the notable exception being bourbon whisky and other straight whiskies in the United States, which must be aged in new, charred-oak barrels. But most spirits producers follow the PR practices of the wine industry by not speaking about or even admitting to the use of oak alternatives. Here is a look at some of the most common of them.
Small Barrels
Small-format (50 liter, 100 liter) barrels do not offer a price savings to distillers, but the increase they offer in the spirits’ contact with wood, relative to volume, often provides the more significant advantage of rapid infusion of barrel character, allowing new producers to speed products to market. To that end they are embraced by a significant percentage of new distilleries, particularly small ones. Yet something is lost in the haste. Extraction of wood components, regardless of barrel treatment or level of char, is dependent upon numerous factors: solvent alcohol levels and barrel surface to liquid volume are only two of them. Time and temperature are also critical components of the innumerous series of reactions that is barrel maturation. As industry consultant David Pickerell notes, to accomplish the same set of reactions, “you would have to raise the temperature so high that it’s not technically feasible. The reaction would be the same but nobody has figured out how to speed up time. You wind up with a hole in your product.” See maturation and oxidation.
Fruit Wood
Those missing pieces include esters that would otherwise be formed through continuous reactions between wood acids and wood sugars; many of the absent characteristics include fruits and flowers. Distillers often include fruit wood among their adjuncts in an effort to provide similar aromas and flavors.
Wine Barrels
The use of port, sherry, and Madeira barrels has a legacy in the whisky industry, even though the bourbon industry historically planted its flag with new charred oak. The Canadian, scotch, and Irish whisky industries have not labored under such constraints; placing an already-aged spirit for a few months in a used fortified wine barrel provides flavor that can be, and is, used to mask green wood elements that derive from oak alternatives that often require some amelioration.
Additions (such as Innerstaves, Stavettes, Oak Spheres, and Sticks in Barrels and Tanks)
Here too, the wine industry has had success, though as with all oak adjuncts, these processes have not been publicized or even widely discussed. Using barrel staves inside non-oak (usually stainless steel) containers is still infrequent in distilleries, but producers have long employed the insertion of staves into older barrels or, more traditionally, the replacement of portions of older barrels (such as barrel heads) with newer wood. Such activities can be summed up with the phrase “barrel maintenance,” and no one thinks less of the producers for doing so. Some distillers find it expedient to “improve” existing barrels by shaving, toasting, or charring a barrel head (or sometimes the entire barrel) or simply inserting new, charred barrel heads. In each case, the wood additions are toasted to the same specifications of any standard barrel and serve to “refresh” any used and depleted barrels.
Oak Chips
These are popular tools within the wine industry. Most wines available in retail stores in the lowest price bracket are fermented with oak chips, if they exhibit oak characteristics at all. Both chips and powder can be easily added to a fermenting vessel, and many winemakers believe that few consumers are able to discern a difference from the sensory notes provided by oak barrels. Longevity seems to be a limiting factor, but wines at such price points are unlikely to be placed in someone’s cellar for long aging.
With the explosion in brown spirits production, such adjuncts are more and more common, even if few in the industry are likely to include those tools in a public tour of the distillery, especially when barrels are so photogenic. In truth, many of the early efforts with these products have arguably been ham-fisted. But oak powder is increasingly used to boost familiar if disrupted notes that consumers assume derive from the accustomed 200-liter barrel.
Cognac production regulations of 1921 speak directly to the use of oak chips, demonstrating that they were at least occasionally utilized at that time, while inner staves date back to the mid-nineteenth century and “are quite mastered,” according to one distiller, reflecting the confidence that they are artfully and subtly deployed when perceived as necessary.
Boisé
A traditional and common component of many brandies is this infusion of old oak, and it is legally controlled and defined by French law for use in all French brandies. This extract can mimic a fairly complete barrel expression, including some of the esters that mark the positive benefits of time in barrel, at least to a degree. But the use of boisé and “petits eaux” (the barrel-aged water used to reduce the spirit to bottling proof) does not contravene the laws and has demonstrably contributed to the success of the wider French brandy industry. See boisé.
Other Oak Infusions
Today, many micro-distillers are utilizing wood infusions created by pressure-cooking wood chips in spirit; this is being described by traditional producers, fairly, as heavy-handed, creating a new kind of boisé characterized by excess bitterness and imbalance.
The wine industry required years of experimentation before its current successes with such adjuncts as described here, so slow improvement is forgivable as long as it is measured and ongoing. As such alternates can reduce costs significantly, distillers will assuredly continue their efforts and experimentation.
Many critics find spirits utilizing these oak alternatives, particularly those aged in small barrels, as lacking in the same constellation of flavors, aromas, and textures that traditional aging offers. But the larger consumer market may not be so discerning.
See also élevage; maturation; and oak.
Bortoletto, Aline M., and André R. Alcarde. “Congeners in Sugar Cane Spirits Aged in Casks of Different Woods.” Food Chemistry 139 (2013): 695–701.
Buxton, Ian, and Paul S. Hughes. The Science and Commerce of Whisky. Cambridge: RSC, 2015.
Jackson, Ronald. Wine Science, Principles and Applications, 4th ed. San Diego: Academic Press Elsevier, 2014.
Jeffrey, David W., et al. Understanding Wine Chemistry. Chichester, UK: Wiley, 2016.
By: Doug Frost