2.31 oz mixed with ice, 0.93 oz of it pure alcohol
Melt
Stirred: +15 % of the pre-batch, +0.35 oz of water
Served
2.31 + 0.35 = 2.66 oz in the glass
Strength
0.93 ÷ 2.66 = 34.9 % ABV as served
Ethanol
0.93 oz × 29.57 ml × 0.789 g/ml = 22 g · about 151 kcal from the alcohol alone
IN THE GLASS
VANILLIN
FROM RYE · from oak barrel aging
Formula
C₈H₈O₃
Mass
152.15 g/mol
IUPAC
4-hydroxy-3-methoxybenzaldehyde
Bourbon's fingerprint, extracted from the charred American oak the law requires for aging. Same molecule as the vanilla bean's signature, so a well-aged bourbon legitimately tastes like vanilla. Chemistry, not metaphor. Cognac, aged rum, tequila reposado all extract vanillin from oak too. Different barrels, same molecule.
An orange rind, squeezed, throws a spray that catches the light. That's d-limonene boiling off. It's roughly 95% of orange peel oil by mass, and the molecule that puts the "orange" in orange anything. Used industrially as a green solvent because the chemistry that dissolves citrus oils also dissolves greasy machinery. The expressed-peel garnish on a cocktail is delivering vaporized limonene to the rim of the glass.
Rye in place of bourbon: a spicier grain bill and a drier finish. Vanillin comes from the barrel either way; the swap trades corn sweetness for pepper.