27 CFR §5.143

1. (a)The class whisky. “Whisky” or “whiskey” is distilled spirits that is an alcoholic distillate from a fermented mash of any grain distilled at less than 95 percent alcohol by volume (190° proof) having the taste, aroma, and characteristics generally attributed to whisky, stored in oak barrels (except that corn whisky need not be so stored), and bottled at not less than 40 percent alcohol by volume (80° proof), and also includes mixtures of such distillates for which no specific standards of identity are prescribed.
2. (b)Label designations. The word whisky may be spelled as either “whisky” or “whiskey”. The place, State, or region where the whisky was distilled may appear as part of the designation on the label if the distillation and any required aging took place in that location (e.g., “New York Bourbon Whisky” must be distilled and aged in the State of New York); however, blending and bottling need not have taken place in the same place, State, or region. However, if any whisky is made partially from whisky distilled in a country other than that indicated by the type designation, the label must indicate the percentage of such whisky and the country where that whisky was distilled. Additionally, the label of whisky that does not meet one of the standards for specific types of whisky and that is comprised of components distilled in more than one country must contain a statement of composition indicating the country of origin of each component (such as “Whisky—50% from Japan, 50% from the United States”). The word “bourbon” may not be used to describe any whisky or whisky-based distilled spirits not distilled and aged in the United States. The whiskies defined in paragraphs (c)(2) through (6) and (10) through (14) of this section are distinctive products of the United States and must have the country of origin stated immediately adjacent to the type designation if it is distilled outside of the United States, or the whisky designation must be proceeded by the term “American type” if the country of origin appears elsewhere on the label. For example, “Brazilian Corn Whisky,” “Rye Whisky distilled in Sweden,” and “Blended Whisky—Product of Japan” are statements that meet this country of origin requirement. “Light whisky”, “Blended light whisky”, and “Whisky distilled from bourbon (rye, wheat, malt, rye malt, or other named grain) mash” may only be produced in the United States.
3. (c)Types of whisky. The following tables set out the designations for whisky. Table 1 sets forth the standards for whisky that are defined based on production, storage, and processing standards, while Table 2 sets forth rules for the types of whisky that are defined as distinctive products of certain foreign countries. For the whiskies listed in Table 1, a domestic whisky may be labeled with the designation listed, when it complies with the production standards in the subsequent columns. The “source” column indicates the source of the grain mash used to make the whisky. The “distillation proof” indicates the allowable distillation proof for that type. The “storage” column indicates the type of packages (barrels) in which the spirits must be stored and limits for the proof of the spirits when entering the packages. The “neutral spirits permitted” column indicates whether neutral spirits may be used in the product in their original state (and not as vehicles for flavoring materials), and if so, how much may be used. The “harmless coloring, flavoring, blending materials permitted” column indicates whether harmless coloring, flavoring, or blending materials, other than neutral spirits in their original form, described in § 5.142, may be used in the product. The use of the word “straight” is a further designation of a type, and is optional.