Craft Cocktail Making: Theory and Structure of Acidity

The dividing line between a cocktail enthusiast and a craft cocktail aficionado is knowledge. Anyone can enjoy a cocktail, and with enough time spent at or behind a bar, attain a good enough working knowledge of brands and flavors of alcohol. Some of these people go on to create a new cocktail, usually starting with a common drink or ratio of spirits to other ingredients and tweaking them to make something pleasant.

Alas, this approach lacks repeatability in creating quality craft cocktails. Craft cocktails are not dump buckets for every neon colored, super sweet liqueur that your distributor is pushing. And they are not made to mask the flavor of alcohol, but to support and sustain it.

Combinations that should work based on the flavors of the components often fail to impress in the glass due to a lack of understanding of those same component's structural elements. Skilled mixologists construct cocktails from some basic building blocks: alcohol, sugar, acidity, and bitterness. A thorough understand of these primary elements can help craft cocktail designers make great drinks with a minimum of waste and trial and error.

Acidity

The cocktail dates back to the earliest parts of the 19th century. The original contained no acidic agents – just a simple mix of spirit, sugar, water, and bitters. But by 1862, Jerry Thomas had entire sections for Sours, Fixes, and Daisies, all of which featured acidity prominently. Certainly, the use of spirit-plus-acidity dates back to the 18th century Punch, which were spirit, water, lemon and sugar, with some other ingredients added for flavoring.

The primary acid in cocktail making is citric acid, a weak organic acid found to varying degrees in all citrus fruit. Limes, lemons, grapefruit, oranges, and even exotic fruits like Seville oranges, yuzu, and bergamots. This is the most common acidulant* in cocktails, with lemon and lime being used much more often than orange or grapefruit juice.

Regardless of the form acidity comes in, it serves the purpose of balancing sweetness in cocktails. When used properly, acidity gives life and refreshment to drinks, lightens their body, and pulls out nuance, in effect acting as a “spacer” between layers of spirit and sweetness. When used improperly and insufficients, cocktails are flat, dull and lifeless, tasting like alcoholic jelly beans.

Lemon juice is the most common source of acidity in cocktails, prized for its neutral flavor and sunny warm aroma. Lemon juice has a pH of around 2.3 – less acidic than lime juice –  so that more must be used to meet a desired level of acidity.

Consider the Jasmine, a cocktail with lemon juice that reveals an interesting quirk that can be useful to cocktail crafters. The Jasmine, invented in 1990 by Paul Harrington, takes a White Lady (which itself is a simple replacement of gin for brandy in a Sidecar), and adds Campari. Campari has a strong flavor of cherry and other red fruit. In this drink, the high proportion of lemon juice makes the flavor of the Campari into one of pink grapefruit. With a little imagination, you can think of it like draining the “shade of red” cherry flavor out of the Campari until it is pink like a grapefruit. Okay, maybe a lot of imagination.

Lime juice is more acidic than lemon juice, with most cultivars having a pH of around 1.8-2. Lime juice also has a strong green/grassy flavor and a bitterness that makes it cut through other flavors in a cocktail. Take the Pegu Club, invented in 1927 in Burma. The Pegu Club modifies a White Lady with lime juice instead of lemon, and some bitters. Here, the lime juice’s grassy notes are front and center, and equal parts of sweet liqueur and lime juice are enough to balance the drink.

Orange juice is more difficult to work into cocktails, as large amounts of it must be used to provide acid balance. Orange juice has over 100 grams of sugar per liter, implying that orange juice will be a dominant source of sweetness and flavor in any cocktail using it as an acidulant. Probably the most famous orange juice cocktail is the Blood and Sand, but even that drink is equal parts Scotch and orange juice, with sweet vermouth and cherry liqueur.

Grapefruit juice is tricky, and should be used with care, as it interferes with a lot of prescription medications. White grapefruits are moderately acid and fairly bitter, with an austere flavor. Pink grapefruits are softer and less bitter, with a red fruit sweetness and some honeyed aromas. Both types of grapefruit juice are high in terpenes, and one fascinating use for that strangely delicious fact is the Shiver, which uses the terpene** explosion of Clear Creek’s Eau de vie of Douglas Fir (which is expensive, hard to find, but tastes fresh young pine needles), and marries it to grapefruit juice and Campari.

Other acid sources include:

The lactic acid found in milk products, which is rounded and soft.
The malic acid found in tree fruit like apples and pears, which is quite acidic, but is buffered by high levels of sugar. Malic acid is also found in wines (including vermouth), along with citric and tartaric acid.
Tartaric acid has an interesting chalky-grape flower aroma and flavor. Try dissolving a pinch of cream of tartar in some warm water and taste it.

Some intrepid cocktail makers use acetic acid found in vinegar to balance cocktails. Acetic acid is a spoilage marker in wines, but when made into a fruit-based syrup called a shrub***, can provide an exotic, heightened aroma to a cocktail. Cocktails containing some form of vinegar are becoming popular again, though the high-toned aroma of acetic acid can be off-putting to some drinkers.

Even though it was not in the original cocktail, acidity has taken a primary role in their construction. Citrus fruit is inexpensive, readily available, and should always be freshly squeezed. Citrus juices oxidize quickly, leading to off flavors and aromas in cocktails. Acidity decreases the texture of a cocktail, increases savoryness (the desire for another sip of a drink), and, when properly employed, brings balance and harmony.

Editors Note: This is the first in a 4-part series on cocktail construction by Kindred Cocktails editor, Zachary Pearson.

Acidity (this article)
Sugar
Bitter
Alcohol

* acidulant: the food science term for ingredients added to increase tartness.

** terpene: pine-like resinous aroma compounds found primarily in conifers and citrus trees.

*** shrub: A fruit-vinegar combination, unrelated Shrubb, a rum liqueur flavored with bitter orange.