Batching is one of the best tools you have for speed and consistency during service. It's also one of the easiest to mess up if you don't account for what happens to the drink between the batch and the glass.
The part people skip is dilution. When you shake or stir a cocktail individually, it picks up roughly 20 to 25% water from the ice. That dilution is part of the drink. It softens the alcohol, opens up the flavors, and brings the cocktail to the temperature where it's meant to be consumed. When you batch and chill in advance, you have to account for that dilution intentionally, or you're serving a version of the cocktail that's too strong and too hot.
The 23.5% water rule. For a stirred cocktail batched without ice, add 23.5% of the total volume as water, then chill the batch. For a shaken cocktail, the same principle applies but texture from ice shards matters, so you'll need to account for that differently (see below).
Example: If your total batch volume before water is 1,000 mL, add 235 mL of water. Stir to combine, chill overnight or for a minimum of 2 hours before service.
What you batch vs. what you don't.
Batch sizes that match your pace. Don't make a 5-liter batch if you typically sell 30 of that cocktail per service. Make what you'll use. Overnight batches left in refrigeration hold well for 3 to 5 days for spirit-forward drinks. Citrus-forward drinks with juice should be used same-day.
Every batch needs: cocktail name, date batched, who batched it, and a "use by" date. Not optional. A new bartender finding an unlabeled bottle in the fridge before a shift will either not use it or use it wrong.
Label the format of the pour as well. If the batch is designed for a 2 oz pour in service, write that on the label. This prevents over-pouring that throws off your cost and your guest's experience.
Batching done correctly means faster service, more consistent cocktails, and less cognitive load on your bartenders during a rush. It doesn't work if the math is skipped.