from Cocktail Codex by Alex Day, Nick Fauchald and David Kaplan with Devon Tarby

Cocktails and sherry have a long shared history. Sherry was used extensively in mixed drinks starting in the late nineteenth century, when it was as common a base ingredient as other spirits. In addition to sherry-based Flips, drinks like the Sherry Cobbler were stars of the era's cocktail boom. Sherry's popularity faded (along with that of other European wines) when the vineyards were devastated by phylloxera (a rootstock-eating aphid) at the turn of the twentieth century. Add to that a lapse in production during World Wars I and II and American Prohibition, and sherry all but disappeared from the radar in the United States.

But now that high-quality sherry has made a triumphant comeback, it's become a valuable ingredient in cocktails. We've found that each style of sherry can bring a host of interesting contributions to a drink: fino offers dryness and salinity; amontillado lends aroma and a beguilingly dry finish; oloroso contributes density and a raisiny flavor; and Pedro Ximénez has a juicy sweetness. Sherry can range from bone-dry to supersweet, the result of two differing methods of aging: biological and oxidative.

All sherry is aged in oak barrels, but in contrast to other wines, where casks are filled to the top to limit the influence of oxygen, sherry casks are filled only four-fifths full. This allows a layer of yeast, called flor, to develop on the young wines inside the cask, creating a protective barrier on top of the wine that prevents oxidation. Meanwhile, the flor feeds off of the sherry as it ages, consuming some components and contributing others, giving sherry its distinctive flavor and texture. This is called biological aging, and it produces the driest forms of sherry: fino and manzanilla. It's also the first step in making amontillado and palo cortado sherries, which are subsequently aged in the presence of oxygen - in other words, they then undergo oxidative aging.

Other sherries never develop flor and are intentionally kept in casks with enough room for oxygen to interact with the sherry. Over time, the sherry oxidizes, developing nutty flavors, and as vapors evaporate out of the cask, the sherry becomes more concentrated. This is how richer sherries are made, such as oloroso and Pedro Ximénez.

Aside from biological and oxidative aging, sherries and a handful of other wines, such as port, are aged differently than most wines and spirits, using a process known as solera aging. While many wines, beers and spirits are aged in barrels after distillation, then later bottled or blended (or even aged again in different casks), in solera systems, wines (and occasionally other spirits, such as rum or brandy) are aged by mixing multiple vintages in the same barrel, a process known as fractional aging. Solera systems were traditionally comprised of several stacked layers of barrels, with new wine being introduced into the top layer of barrels, and each layer beneath holding progressively older blends. Today, the barrels often aren't stacked, but the process remains the same: several times a year, some of the sherry from the oldest barrels (the solera for which the system is named) is bottled and replaced with the blend in the next-oldest barrels, which is in turn replenished by the blend in the next-oldest barrels, and so forth, with new wine, called sobretabla, being used to top off the uppermost barrels. None of the barrels is ever completely drained, and because of this, sherry from a solera can have trace amounts of extremely old wine, in some cases stretching back centuries. In addition to being very cool, this also produces wines that are amazingly consistent from year to year - a rarity in the wine industry. 

How We Use Sherry in Cocktails

We generally approaching using sherry in cocktails in four ways:

1. As a simple substitution for a similar ingredient; for example, fino sherry in place of a dry vermouth, or oloroso sherry in place of a sweet vermouth.
2. As the drink's sole base, building a cocktail's flavor on the traits of a particular style or bottle of sherry.
3. As a split base, typically with slightly more sherry than spirit (1 or 1.5 ounces sherry plus 1 ounce spirit) - a winning combination as a base for both citrusy and spirituous cocktails, as in the Fair Game, La Valencia and Fuji.
4. In tiny, nearly imperceptible amounts as a seasoning, an approach that works especially well with salty finos or amontillados.