The relevant section of the regs for labeling claims on whiskies, 27 CFR 5.22(b)(1)(i), reads: Subparagraph (iii) continues: 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. Eric 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.