Phantasm thiol powder also: Phantasm, Thiol precursor powder
Sauvignon Blanc grape skins → tropical thiol release in fermentation. Limited supply, big impact.
What it is, in plain English
Phantasm is a powder made from freeze-dried Marlborough Sauvignon Blanc grape skins. Sauvignon Blanc grapes (especially Marlborough's) are unusually rich in thiol precursors — bound molecules that release as free thiols (3SH, 3SHA) during yeast fermentation. Free thiols are responsible for tropical fruit aromas (passionfruit, guava, grapefruit) in both wine and beer. When Phantasm is added at the whirlpool, the thiol precursors enter the wort and get unlocked during fermentation, dramatically boosting tropical-fruit character. Best paired with thiol-releasing yeast strains (Berkeley Tropics, Omega Cosmic Punch, London III). Supply is limited and dependent on the annual NZ Sauvignon Blanc harvest.
The technical version
Sauvignon Blanc grape skins are freeze-dried and milled into a fine powder rich in cysteine- and glutathione-bound thiol precursors (specifically Cys-3SH and Glu-3SH). These bound molecules are flavor-inactive on their own. During fermentation, certain yeast strains express enzymes that cleave the bonds and release free thiols (3-sulfanylhexan-1-ol = 3SH; 3-sulfanylhexyl acetate = 3SHA), which carry intense tropical aromas at very low concentrations.
How brewers use it
Add at whirlpool, dose between 4-12 g/L (6 g/L is the sweet spot per Escarpment Labs / Phantasm.NZ). Higher doses provide more potential thiol release but yeast strain choice ultimately limits how much gets converted. Pair with thiol-positive yeasts: Escarpment Thiol Libre, Berkeley Tropics, Omega Cosmic Punch / Luna / Yuzu, Lallemand Verdant. Mash hopping with thiol-containing hops (notably Saaz, then Cascade) can stack with Phantasm. Light Munich-style malts work well as a base — lower kilned malts preserve the precursor environment. New Image Brewing in Colorado has documented dialing in 'Phanny Pack' iterations to optimize specific recipe parameters.
Who uses it
WeldWerks (Greeley, CO) and New Image (Arvada, CO) are the public Phantasm champions. Treehouse, Other Half, and most top-tier hazy producers have used it. Hop Culture and PorchDrinking covered the early-adoption wave. Phantasm has been called the closest thing to a true 'cheat code' in modern hazy brewing.