A balanced at-home sweet and sour mix made from fresh lemon and lime juices and a 1:1 simple syrup. Use in sours, margaritas, and other cocktails that call for sour mix for a brighter, fresher flavor than store-bought mixes.

1) Make the simple syrup: combine 1 cup (200 g) granulated sugar and 1 cup (240 ml) water in a small saucepan. Heat over medium, stirring until the sugar dissolves and the mixture is clear. Bring just to a gentle simmer for 30–60 seconds, then remove from heat and cool to room temperature.
2) Juice the citrus: squeeze about 1 cup (240 ml) fresh lemon juice (≈4–6 lemons) and 1 cup (240 ml) fresh lime juice (≈8–10 limes). Strain through a fine-mesh sieve to remove seeds and excess pulp if you prefer a smoother mix.
3) Combine: in a clean container or bottle, combine 1 cup (240 ml) cooled simple syrup, 1 cup (240 ml) lemon juice, and 1 cup (240 ml) lime juice. Stir or shake until fully blended. Taste and adjust: add up to 1–2 tablespoons more syrup if you prefer sweeter, or a splash more lemon/lime if you prefer tarter.
4) Chill and store: transfer to a sanitized airtight bottle or jar and refrigerate. Shake before each use, as separation may occur.
Optional pasteurization for longer life: warm the finished mix gently to 160–165°F (71–74°C) for 15–30 seconds (do not boil) and immediately cool in an ice bath, then bottle. Note: heat will slightly change the fresh flavor.