An Old Fashioned at a busy bar takes longer than it should. The math is built into the drink — sugar in the glass, bitters, a measured pour, a slow stir over ice — and on a Saturday night that math takes two and a half minutes. A bottled Old Fashioned takes ten seconds. The sugar is dissolved, the bitters are blended, the dilution is dialed; the bartender pours, expresses the peel, and moves on.
Bourbon is the only choice that matters
An Old Fashioned is roughly 90 percent whiskey by volume. The bottle's character is whatever the whiskey's character is — there is nowhere else for it to come from. Pick a 100-proof bourbon with shoulders: Old Grand-Dad Bonded, Wild Turkey 101, Buffalo Trace if you can find it. Anything thin or hot will be thin and hot in the bottle for a month.
Demerara, not simple
The sugar in an Old Fashioned should be demerara syrup at 2:1 — twice the sugar to one part water by weight. Simple syrup at 1:1 will work, but the drink reads thinner and the molasses notes of demerara are the entire point of the modern Old Fashioned vocabulary. The /ingredients/ page has a recipe for rich demerara at the ratio this bottle expects.
Dilution: 17 percent water
Old Fashioneds are notoriously under-diluted by inexperienced bartenders and over-diluted by experienced ones. A measured 17 percent water by volume in the bottle puts the drink in the right place at the moment of pour, and a single large cube continues to soften it across the sip.
Cap, refrigerate at least two hours. Overnight is better. Label the bottle with the batch date; refrigerated, it holds 60 days without measurable change.
Service
Pour 3.1 oz over a single large cube in a double Old Fashioned glass. Express an orange peel over the surface — twist it firmly so the oil sits visibly on the drink — and drop it in. A brandied cherry is optional and traditional; a maraschino cherry of the wrong sort is a deal-breaker.