Ahtanum is an American aroma hop, named for the Ahtanum Ridge growing area in Washington State's Yakima Valley, developed as a cross related to Cascade's lineage. It runs a comparatively narrow and moderate alpha acid range of 5.7-6.3%, placing it firmly in aroma-hop territory rather than bittering use.
Its character sits close to Cascade's — citrus and floral notes with a distinct grapefruit lean — which makes it a natural substitute in recipes built around Cascade or Amarillo when either of those is unavailable. Ahtanum tends to read slightly more resinous and less overtly sweet-citrus than Amarillo, and slightly more floral than a straight Cascade.
Because of its moderate, stable alpha acid range and clean citrus-floral profile, Ahtanum works well in late-boil and dry-hop additions for American pale ales and session IPAs where a supporting, rather than dominating, citrus character is the goal. Check its exact alpha acid on the current lot's Certificate of Analysis before finalising a bittering-charge weight — the IBU calculator turns that figure into an actual number rather than a guess.
Ahtanum has never reached the same commercial prominence as Cascade or Amarillo, but it remains a reliable, moderately-priced choice for brewers building a citrus-forward pale ale who want a slightly more resinous edge than Cascade alone provides, without reaching for a more expensive proprietary variety, and without the supply swings a single-farm proprietary hop can carry.