Whiskey (sometimes spelled whisky) is an amber-colored distilled spirit made out of fermented grain (most often rye, wheat, corn, or barley). Most whiskeys are aged in wooden casks before bottling and have a minimum of 40 percent alcohol by volume (ABV). There are many different whiskey types, usually distinguished by their place of origin, types of grain, blending process, or aging process, and each will vary in flavor. However, whiskey is commonly described as warm, spicy, sweet, caramelly, or toasty.

The word whiskey comes from the Gaelic “uisce beatha” or “uisge beatha,” meaning “water of life.”

There are a few simple ingredients that comprise whiskey:

• Grain mash: Most alcohol-making begins with an agricultural product that will undergo a fermentation process. A fermentable whiskey base is usually a mixture of grains, like malted barley, rye, corn, or wheat, which often dictate the flavors and designation of the final product. For instance, the mash bill in rye whiskey should contain at least 51 percent rye, while Kentucky bourbon must have at least 51 percent corn.
• Water: After the distillation process, whiskey makers will add water to the product to achieve the desired alcohol by volume.
• Optional additives: According to US regulation, whiskey can have up to 2.5 percent added flavors (whiskey with no added flavors is classified as “straight”). Many whiskey brands choose to add botanicals, spices, flavorings, or color during distillation or aging to achieve distinctive character or appearance in their liquor.
• Time: Before bottling, whiskey is aged in wooden casks or barrels after distillation to bring out different flavors and colors. In the US, whiskey has a minimum aging requirement of two years, though many producers age the spirit for around 10 to 12 years.

Most whiskey makers follow a few basic steps to produce whiskey:

1. Combine the base ingredients. To make a fermentable base, whiskey makers will mix grains—like wheat malt, flaked maize, or rye—with water and yeast. They then heat and stir the mixture (sometimes called “whiskey mash”) to make sure it’s well combined and ready to ferment.
2. Ferment the base. Whiskey makers then store their base mixture for a specified amount of time—from one to two weeks—to fully ferment the mixture. During this step, the compounds begin to break down and produce a simple, natural alcohol called ethanol or ethyl alcohol.
3. Strain the mixture. Once fermentation is complete, whiskey makers strain off the liquid from the fermented solids. They’ll discard the solids and use the liquid (ethanol) to make vodka.
4. Distill. Distillation is a process that purifies a liquid by heating and vaporizing it, then collecting the vapor as it recondenses into a liquid. The resulting liquid is considered purer (since it leaves behind many impurities when it evaporates) and more alcoholic.
5. Collect and sort the distillate. The liquid that whiskey distillers have after distillation isn’t all the same—as ethanol distills, the resulting liquid changes. The first 35 percent of a distillation results in an ethanol product that contains methanol or acetone and can be highly volatile or toxic—containers of this liquid are called the “foreshots” and the “heads,” and distillers usually throw them out. The following 30 percent contains the “hearts,” which are the best product. The final 35 percent are the “tails,” which are impure but can be kept and redistilled for a little more development.
6. Age the liquor. After distilling, whiskey goes through an aging process in which whiskey makers store the spirit in wooden barrels for at least two years. Distilleries use different aging methods, including new oak barrels, white oak barrels, charred barrels, or barrels soaked in wine or sherry.
7. Dilute. To ensure the proper alcohol content, whiskey makers test and dilute their product with filtered water before or after aging (sometimes both).
8. Bottle. The final step is the bottling process, in which whiskey makers add the final product to labeled bottles. Once the whiskey is bottled, it stops aging.

There are many different types of whiskey, usually distinguished by their place of origin, types of grain, blending process, or aging process:

1. Blended whiskey: A blended whiskey is a mixture of whiskeys, potentially produced by different distilleries.
2. Bourbon whiskey: Bourbon is American whiskey, often (though not exclusively) produced in Kentucky, containing at least 51 percent corn in its mash bill or grain makeup. Bourbon must be aged in newly charred oak barrels if produced in the United States, making for a typically nutty flavor profile and a mellow, caramelized sweetness.
3. Canadian whisky: This type of whisky must be produced and aged in Canada, have a minimum of 40 percent ABV, and age at least three years in wooden barrels no larger than 700 liters. Canadian whiskey can also contain caramel and other flavorings or additives, leading to diverse tastes between brands.
4. Irish whiskey: A spirit must be produced from malt, cereal grain, and barley and distilled, aged, and bottled in Ireland to qualify as Irish whiskey. Irish whiskey must be aged in wooden casks for a minimum of three years. The more muted, malt character of Irish whiskey shines most when the spirit is aged in less conventional vessels like sherry casks or rum casks.
5. Japanese whisky: Whisky is bottled in Japan, but it isn’t necessarily distilled or aged in the region. Some Japanese whisky draws immediate comparisons to Scotch whisky, while other producers are continually evolving, harnessing the unique qualities of indigenous Japanese oak.
6. Rye whiskey: Rye whiskey contains at least 51 percent rye in its mash bill. Like bourbon, rye must be aged in newly charred oak barrels if produced in the United States. In general, rye is lighter-bodied than many other whiskeys; you can identify it by its tingly spiciness.
7. Scotch whisky: Scotch must be distilled, aged, and bottled in Scotland. Scottish law mandates that scotch be aged in oak casks for a minimum of three years. Scotch malt whisky producers traditionally operate in five specific Scottish regions: the Highlands, the Lowlands, Campbeltown, Islay, and Speyside. Scotch receives its smoky character from peat—a dense moss lit on fire to dry out the malted barley from the distillation. Unless a recipe calls for a particular scotch by producer or style, a blended scotch will be your best bet for most cocktails. Use a single-malt scotch if you're drinking it neat or on the rocks.
8. Single-malt whiskey: A single-malt whiskey comes from a single distillery and only contains one type of malted grain. A single-malt whiskey bottle may include whiskey from several different casks—unless it’s a single cask whiskey.
9. Tennessee whiskey: A subtype of Bourbon, Tennessee whiskey is filtered through sugar maple charcoal before it is aged. This filtering method is the Lincoln County Process, and it is what gives Tennessee Whiskey its own unique flavor.