27 C.F.R. § 25.15 : Alcohol, Tobacco Products and Firearms — ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY — ALCOHOL — BEER — DEFINITIONS —STANDARDS FOR BEER — Materials for the production of beer

(a) Beer must be brewed from malt or from substitutes for malt. Only rice, grain of any kind, bran, glucose, sugar, and molasses are substitutes for malt. In addition, you may also use the following materials as adjuncts in fermenting beer: honey, fruit, fruit juice, fruit concentrate, herbs, spices, and other food materials.
(b) You may use flavors and other nonbeverage ingredients containing alcohol in producing beer. Flavors and other nonbeverage ingredients containing alcohol may contribute no more than 49% of the overall alcohol content of the finished beer. For example, a finished beer that contains 5.0% alcohol by volume must derive a minimum of 2.55% alcohol by volume from the fermentation of ingredients at the brewery and may derive not more than 2.45% alcohol by volume from the addition of flavors and other nonbeverage ingredients containing alcohol. In the case of beer with an alcohol content of more than 6% by volume, no more than 1.5% of the volume of the beer may consist of alcohol derived from added flavors and other nonbeverage ingredients containing alcohol.

27 C.F.R. § 25.15

T.D. TTB-21, 70 FR 235, 1/3/2005