Built in the glass: +5 % of the pre-batch, +0.33 oz of water
Served
6.5 + 0.33 = 6.83 oz in the glass
Strength
0.8 ÷ 6.83 = 11.7 % ABV as served
Ethanol
0.8 oz × 29.57 ml × 0.789 g/ml = 19 g · about 131 kcal from the alcohol alone
IN THE GLASS
DIACETYL
FROM WHITE RUM CANE · the butter note
Formula
C₄H₆O₂
Mass
86.09 g/mol
IUPAC
butane-2,3-dione
The butter note. Wanted in oak-aged Chardonnay and certain ales (English bitter, Czech pilsner) where a controlled amount adds body; unwanted at high concentrations, where it slides into movie-theater-popcorn territory. Yeast produces it as an intermediate during fermentation and reabsorbs it during conditioning. A rushed beer that skipped its conditioning rest often carries diacetyl as an off-flavor the brewer didn't intend.
A purine alkaloid that blocks adenosine receptors in the brain, so the tiredness signal never lands. Coffee, tea, cocoa, mate, guarana, kola: all unrelated plants, all evolved caffeine independently as an insecticide. Humans inherited a tolerance for what bugs can't handle.
Lemon's defining note: technically a mix of two geometric isomers (geranial and neral) that read as the same aroma to the nose. Lemon peel, lemongrass, lemon verbena, and Indian chai all carry it. In cocktails it's what a lemon twist contributes that lemon juice can't: the volatile expressed from the oil glands, not the acid from the pulp.
White rum, lime and cola. Coca-Cola, new to Havana around 1900, met Bacardí rum and a slice of lime. Citral from lime cuts cola's phosphoric acid and caramel, and ethyl esters from white rum sustain.
PROVENANCE
Created in Havana after the Spanish-American War; American soldiers stationed in Cuba brought Coca-Cola with them, and bartenders combined it with the local Bacardí rum and lime. The name, 'Free Cuba', was the war cry of Cuban independence fighters. The drink became globally famous through 1940s American GIs in WWII and the 1945 Andrews Sisters song 'Rum and Coca-Cola.' Cuba Libre uses lime; the lime-less version is simply 'rum and Coke.'
