Malt whisky is whisky that is made from a fermented mash produced primarily from a malted grain. Unless otherwise indicated, it is generally assumed that the primary grain is barley, although whisky is also made using malted rye or other grains. A whisky made from malted rye is usually called a rye malt whisky instead of just a malt whisky.
If the product is made exclusively from a single grain at a single distillery (along with other restrictions), it is called a single malt whisky. Although this ordinarily refers to whisky made from malted barley, at least one brand of "single malt" whisky is made from rye.
The exact definition of a "malt whisky" and a "single malt whisky" and the restrictions governing its production vary according to the regulations governing the marketing of whisky in the local jurisdiction.
In the United States Code of Federal Regulations, the Standards of Identity for Distilled Spirits define a "malt whisky" as a whisky produced at an alcohol by volume (abv) level not exceeding 80% from a fermented mash of not less than 51% malted barley grain and stored for aging in charred new oak containers at less than 62.5% abv. The regulations also define a "rye malt whisky" in a corresponding manner using rye grain. If such a whisky has been aged for at least two years, contains no added coloring and flavoring, and has not been blended with neutral spirits or other types of whisky, the additional adjective straight can be applied, as in "straight malt whisky" and "straight rye malt whisky". If the whisky is not totally straight but at least 51% of its content is "straight malt whisky", the word "malt" can still be used, but the product must be described as a "blend", as in "blended malt whisky" or "malt whiskey – a blend". There is no aging requirement for the parts of a blended whiskey other than the part that is straight whiskey – e.g., the product may contain neutral spirits that have not been aged and have been made from other types of grain.
In Scotch whisky regulations, malt whisky must be made using at least some barley and must be aged for at least three years, the use of new barrels is not required, the distillation and aging can use higher levels of alcohol by volume (which can result in a "lighter" but less flavorful whisky), and (E150A) caramel coloring can be added (but no other additives are allowed).
Canadian whisky regulations are generally more liberal, allowing the addition of flavoring agents as well as caramel, and not specifying the use of any particular type of grain when making malt whisky. There is no maximum limit on the alcohol level of the distillation or aging for Canadian whisky, so the bulk of the distilled content (often more than 90 percent) may be neutral spirits or near-neutral spirits rather than "straight" whisky. Similar to the regulations for the aging of Scotch, the aging requirement for Canadian whisky is three years, and the use of new barrels is not required.
- Old Potrero Single Malt Straight Rye Whiskey bottle photo.
- "Standards of Identity for Distilled Spirits, Title 27 Code of Federal Regulations, Pt. 5.22" (PDF). Retrieved 2008-10-17.
- The Scotch Whisky Regulations 2009, The National Archives, 2009.
- The Scotch Whisky Regulations 2009: Guidance for Producers and Bottlers, Scotch Whisky Association, February 12, 2009.
- "Canadian Food and Drug Regulations (C.R.C., c. 870) – Malt Whisky (B.02.013)". (Access date March 25, 2015.)
- "Canadian Food and Drug Regulations (C.R.C., c. 870) – Canadian Whisky, Canadian Rye Whisky or Rye Whisky (B.02.020)". (Access date December 15, 2010.)