Topaz was released in 2008 by Hop Products Australia, part of the same breeding stable that produced Galaxy, and developed to fill a specific gap that pure aroma hop didn't cover: genuine high-alpha bittering capacity grown on Australian soil, sparing brewers from needing to import an American or German bittering hop to pair with their Australian aroma varieties.
At 14-17% alpha acid, Topaz delivers efficient bitterness, with a black currant and tropical fruit aroma that carries some of the same general fruit-forward DNA as its more famous sibling Galaxy, even though Topaz was bred primarily for its alpha acid rather than to compete directly on aroma. That dual capability — real bittering strength with a genuinely pleasant, non-neutral aroma — makes it more versatile than a purely functional bittering hop like Magnum. Topaz's alpha is among the strongest and most reliably efficient Australia currently produces commercially, which the IBU calculator will turn into a real figure for a bittering charge. Bravo and Pacific Gem both serve as substitutes given their own black-currant-adjacent character at a similarly high alpha range, though from entirely different growing traditions. Double IPA and Australian-style pale ale both use Topaz, generally as the bittering charge underneath a more aroma-focused Galaxy or Vic Secret late addition. Topaz's alpha ceiling runs above both Pacific Gem's and Galaxy's, why it's the one of the three most often chosen specifically for the bittering role rather than shared aroma duty.