Crater Lake Hazelnut Espresso Vodka was built to do one thing in a cocktail shaker that neutral vodka cannot: act as a fatty, aromatic bridge between bourbon’s charred oak tannins and fresh espresso’s dark roast lipids. Getting the substitution right requires a precise dosing ratio, a 90-second espresso rest, and 15 seconds of piston-force shaking. This guide covers the complete protocol.