If you experiment with cocktails often, there are a few ingredients you\u2019ll see over and over. Particularly common are vermouth and bitters. They form the composition of countless classic cocktails from the Manhattan to the Alaska, the Bobby Burns, Adonis or Rob Roy.\r\n\r\nWhile the craft bitters boom of recent years has led to volumes being written about bittering-agents in cocktails, the role of vermouth is often overlooked.\r\n\r\nSo how did this fortified wine become such an integral part of so many drinks?\r\nVermouth, defined\r\nVermouth starts with a base of wine or grape must. In Europe, regulations mandate that the final product be at least 75% wine, with an alcohol by volume (abv) of 14.5\u201322%.\r\n\r\nThe wine base is fortified and aromatized with ingredients like citrus peels, herbs, spices and a bittering agent. Traditionally, the bittering component is wormwood, but these days you\u2019ll find non-European offerings labeled vermouth (or colloquially lumped into the vermouth category) that achieve bittering through mugwort, cinchona bark or a variety of roots and other ingredients. However, for many purists, along with E.U. regulations, if it doesn\u2019t have wormwood, it\u2019s not vermouth.\r\n\r\n\r\n\r\nPart of the fun of vermouths are the wide range of flavor profiles you\u2019ll find. Wine acts as a canvas for producers to create limitless combinations of herbs and aromatics, and there\u2019s a staggering array of bottlings.\r\n\r\nHowever, for the purpose of the at-home bartender, we\u2019re breaking down three categories of vermouth that are commonly called for in cocktails: sweet, dry and blanc/bianco.\r\nSweet vermouth\r\nAs its name suggests, these red vermouths are usually the sweetest offerings. In cocktails, they\u2019re commonly used as a more aromatic replacement for other sugar-based options. The primary difference between an Old Fashioned and a Manhattan? The former uses a sugar cube where the latter uses an ounce of sweet vermouth.\r\n\r\nWhile some sweet vermouth is still made from a red wine, it\u2019s more common these days for producers to use white grapes, with the red coloring coming from caramelized sugars.\r\n\r\nClassic cocktails that use sweet vermouth include the Manhattan and Negroni.\r\n\r\n\r\nDry\r\nAs with traditional wine, a dry vermouth has less sugar. This can range from extra-dry to dry offerings, though other factors like barrel aging can sometimes affect the perception of sweetness without increasing the total grams of sugar.\r\n\r\nDry vermouths often showcase more herbal, floral or citrus notes like lemon peel. They are also often used by bartenders in spirits-forward cocktails like the Martini or El Presidente to add a touch of acid.\r\nBlanc/Bianco\r\nCalled \u201cblanc\u201d vermouths in France and \u201cbianco\u201d in Italy, these often tend to split the difference between sweet and dry vermouth and can be comparable to an off-dry wine.\r\n\r\nIn cocktails, blanc/bianco vermouths are used in drinks where a small amount of sugar may be desired to balance bitter ingredients that could create undesirable astringency, but where sweet vermouth may be too cloying. A great example of this is the White Negroni, where a bianco vermouth makes up for the absence of Campari\u2019s sugar.\r\n\r\nWorth noting, some cocktails like the Corpse Reviver #2 or Vesper Martini may call for ingredients like Lillet Blanc or Cocchi Americano, which fall under the vermouth-adjacent category of fortified aromatic wines that don\u2019t specifically contain wormwood. However, these drinks would be equally well served by substituting blanc/bianco vermouths.\r\nWhy is vermouth so common in cocktails?\r\nVermouth is often said to \u201cbring out the flavors\u201d of a cocktail base like whiskey or gin, but what does that really mean?\r\n\r\nIt\u2019s a theme we touch on again and again in Bartender Basics: dilution.\r\n\r\nReducing the alcohol-by-volume of a drink by cutting a high-proof spirit with a lower-proof fortified wine reduces the taste of ethanol, or that boozy, stinging-the-back-of-your-nose perception of alcohol that can overwhelm your ability to appreciate more subtle flavor and aroma compounds. It\u2019s not unlike adding a splash of water to Scotch\u2014the reduced booziness allows you to pick up on notes of caramel, vanilla, peat or oak rather than simply alcohol.\r\n\r\nThis also helps illustrate why \u201cdry,\u201d when used in the context of cocktails, isn\u2019t always the same as in wine. If you make a Martini with a full ounce of bone-dry vermouth, the cocktail doesn\u2019t become sweeter. It simply tastes less boozy. Of course, dilution could be accomplished by stirring or shaking a cocktail with ice. Vermouth\u2019s unique, complex and varied aromatics dilute drinks while creating new flavors and dimensions.\r\n\r\n\r\n\r\nPlaying with different types of vermouth isn\u2019t unlike experimenting with herb and spice combinations when cooking, to find what brings out desirable flavors in your main ingredients. Fan of a Moscow Mule? Try making a Boulevardier with a vermouth that offers ginger notes. Enjoy Palomas in the summertime? Reach for a grapefruit-forward vermouth in your next Negroni.\r\n\r\nVermouth is also common in spirits-forward drinks to include an element of fruit in a cocktail without juices. Owing to its wine base, vermouth creates the best middle ground between distilled spirits and drinks in the sour family that incorporate higher citric acid and pure fruit juices, like a gimlet (lime) or whiskey sour (lemon).\r\n\r\nSo why is vermouth so often found in cocktails? Versatility. There are few other ingredients that can combine such a range of flavor, aroma and textural profiles into a single pour. Vermouth allows you to create a cocktail that gives the impression of a staggering number of ingredients, using fewer bottles.