In these days of the explosion of craft beers, it becomes more and more important to determine what truly IS a beer. This is what the Australian government defines as beer (from the recently amended Excise Tariff Act 1921):
Beer means a brewed beverage that:
(a) is the product of the yeast fermentation of an aqueous extract, being predominantly an aqueous extract of cereals:
(i) whether the cereals are malted or unmalted; and
(ii) whether or not the aqueous extract contains other sources of carbohydrates; and
(b) contains:
(i) hops, or extracts of hops, such that the beverage has international bitterness units of not less than 4.0; or
(ii) other bitters such that the beverage has a bitterness comparable to that of a beverage mentioned in subparagraph (i); and
(c) contains not more than 4.0% by weight of sugars; and
(d) has not had added to it, at any time, artificial sweetener; and
(e) may have had added to it, at any time, other substances, including flavours, but only if, in the case of substances that contain alcohol (other than spirit distilled from beer), the alcohol did not add more than 0.5% to the total volume of the final beverage; and
(f) may have had added to it, at any time, spirit distilled from beer, but only if that spirit did not add more than 0.5% to the total volume of the final beverage; and
(g) contains more than 1.15% by volume of alcohol.