The relevant section of the regs for labeling claims on whiskies, 27 CFR 5.22(b)(1)(i), reads:
‘‘Bourbon whisky’’, ‘‘rye whisky’’, ‘‘wheat whisky’’, ‘‘malt whisky’’, or ‘‘rye malt whisky’’ is whisky produced at not exceeding 160° proof from a fermented mash of not less than 51 percent corn, rye, wheat, malted barley, or malted rye grain, respectively, and stored at not more than 125° proof in charred new oak containers; and also includes mixtures of such whiskies of the same type.
Subparagraph (iii) continues:
Whiskies conforming to the standards prescribed in paragraphs (b)(1)(i) and (ii) of this section, which have been stored in the type of oak containers prescribed, for a period of 2 years or more shall be further designated as ‘‘straight’’; for example, ‘‘straight bourbon whisky’’, ‘‘straight corn whisky’’, and whisky conforming to the standards prescribed in paragraph (b)(1)(i) of this section, except that it was produced from a fermented mash of less than 51 percent of any one type of grain, and stored for a period of 2 years or more in charred new oak containers shall be designated merely as ‘‘straight whisky’’. No other whiskies may be designated ‘‘straight’’. ‘‘Straight whisky’’ includes mixtures of straight whiskies of the same type produced in the same State.
So to be labeled "rye whisky", the stuff in the bottle must be distilled to 160 proof or less from a mash of at least 51% rye, then barreled in charred new oak at no more than 125 proof. (Note that there's no age requirement.) To be labeled "straight rye whisky", the stuff in the bottle must meet all those requirements and then also have been aged for at least two years (in those same charred new oak barrels).
I searched the regs pretty thoroughly and did not find anything that indicates there's a ceiling on the proportion of rye that can be included in the mash of something labeled "rye whisky" or "straight rye whisky", so it's likely that Anchor's ryes that aren't labeled "straight" lack that designation, as eje suggested, because they're aged in something other than charred new oak.
Edit: Oh, I forgot to mention -- the 79% cap slkinsey mentioned probably came from confusing the regulatory destinction between "bourbon whisky" and "corn whisky" as having something to do with rye. The regs stipulate that bourbon be made from a mash of at least 51% corn, but then further state that anything made from 80% corn or more cannot be called bourbon and must instead be called "corn whisky". But none of this 80%-cap stuff has anything to do with rye.
Edited by E. M. Pashman, 10 January 2007 - 03:47 PM.