Rhubarb liqueur has a delightful rhubarb flavor (and color), and it's just sweet enough to enjoy on its own. Or, add it to your favorite rhubarb cocktails!
Wash the rhubarb stalks and trim off the leaves and any damaged ends. Discard the leaves (they contain toxic levels of oxalic acid). Chop the stalks into 1/2 to 1 inch pieces.
Combine the chopped rhubarb and sugar in a 1/2 gallon mason jar. Cap loosely and let macerate at room temperature for 24 hours, shaking once or twice. The rhubarb will release juice and the mix will turn deep pink.
Pour the entire 750 ml bottle of vodka over the macerated rhubarb. Don't drain off the released juice; you want it in the mix. Cap the jar tightly.
Infuse at room temperature, out of direct sunlight, for 4 to 6 weeks. Shake gently every few days for the first two weeks, then leave it alone.
Strain through a fine mesh strainer, pressing gently on the solids. Reserve the spent rhubarb for ice cream topping or quick bread batter.
Taste the strained liqueur and add additional sugar (or 1:1 simple syrup) to taste. Most people add another 1/4 to 1/2 cup of simple syrup.
Bottle in clean glass bottles, cap tightly, and store at room temperature out of direct sunlight.
Notes
Sugar ratio: This recipe uses 1 cup sugar (1/2 pound) to 1 1/2 pounds chopped rhubarb, a 1:3 ratio by weight. Some recipes use as much as 1:1, which would be a full 3 cups of sugar total. Sweeten to taste after straining; it's easier to add than to take away.Why sugar before vodka: Rhubarb won't release its red color into vodka alone. The 24-hour sugar macerate draws out both color and juice before the alcohol goes in, which is what gives this liqueur its rose-pink color.Frozen rhubarb: Works fine. Thaw and drain off extra liquid before measuring. The macerate stage will move faster with frozen rhubarb (overnight is enough).Alcohol substitutions: White rum and gin both work well. Whiskey and brandy will dominate the rhubarb flavor.Color tips: Red rhubarb stalks make a vivid rose liqueur; green stalks make a pale gold liqueur. The technique is the same. Sort and use the reddest stalks for the most dramatic color.Shelf life: High alcohol content keeps this liqueur shelf stable indefinitely from a safety standpoint. Plan to use within a year for peak flavor; the color fades and flavor mellows after that.Storage: Room temperature, out of direct sunlight. For a chilled drink, transfer to the freezer about 30 minutes before serving (alcohol won't freeze at this proof).What to do with the strained rhubarb: The macerated rhubarb is sweet, boozy, and still tasty. Use it to top vanilla ice cream, fold into muffins or quick bread batter, stir into yogurt or oatmeal, or freeze for later baking projects.