Beer. Beer, ale, porter, stout, and other similar fermented beverages (including sak and similar products) of any name or description containing one-half of one percent or more of alcohol by volume, brewed or produced from malt, wholly or in part, or from any substitute for malt. Standards for the production of beer appear in 25.15.
27 CFR § 25.11
When used in this part, where not otherwise distinctly expressed or manifestly incompatible with the intent thereof, terms have the meanings given in this section.