Start with a proven ratio
Many sours begin around two parts spirit, one part citrus and one part sweetener. Treat that as a starting point rather than a law: citrus acidity and syrup sweetness vary between batches.
Taste with a clear question
Taste a tiny drop before serving. Is the drink sharp, flat or sticky? Change one element at a time and taste again.
- Too sharp: add a small barspoon of syrup.
- Too sweet: add a few drops of fresh citrus.
- Too strong: allow a little more dilution or mixer.
- Too flat: add citrus, bitters or saline solution.
Record your best version
A 5 ml difference can be noticeable. Note the brand, amount and technique when the balance is right so you can repeat your version exactly.