Batching cocktails for a crowd

The best host at a party is the one who is not behind the bar. A bottle of Negroni in the freezer pours twenty drinks in two minutes with no shaker, no stirring and no queue. Batching is arithmetic plus two rules about what to leave out. Get the water right and nobody can tell the difference; Dave Arnold proved it blind.

What you need

• The single-serving recipe you trust, in ounces or milliliters.
• A measuring jug marked in milliliters, a funnel, and a kitchen scale if you prefer weight.
• Still filtered water, chilled.
• Clean glass bottles with airtight caps (swing-top bottles reseal; 750 ml spirit bottles work if cleaned and dried).
• Masking tape, a marker, fridge or freezer space, and plenty of ice for service.

Step 1: choose a drink that batches

Spirit-forward stirred drinks batch best. They hold their shape for weeks, and their alcohol keeps them from freezing solid. The three house examples:

• Negroni: 1 oz / 30 ml gin, 1 oz / 30 ml Campari, 1 oz / 30 ml sweet vermouth.
• Boulevardier: 1.5 oz / 45 ml bourbon, 1 oz / 30 ml Campari, 1 oz / 30 ml sweet vermouth.
• Manhattan: 2 oz / 60 ml rye, 1 oz / 30 ml sweet vermouth, 2 dashes aromatic bitters.

Step 2: scale

Multiply each line by the number of servings, then add 10 percent for the pour that spills and the guest who asks twice. For 12 Negronis: 12 x 30 ml = 360 ml each of gin, Campari and vermouth; call it 400 ml each. That is 1200 ml of undiluted drink.

Bitters do not scale in a straight line. A dash is about 1 ml, and twelve dashes in a bottle read louder than one dash in a glass. Start at two-thirds of the multiplied amount (for 12 Manhattans, 16 dashes instead of 24) and taste.

Step 3: add the water the ice would have added

A stirred drink takes on about 20 percent water on its way to the glass; a shaken drink about 25 percent. A bottle never touches ice, so you pour that water in. The working range from Punch, Death and Co and Difford's is 20 to 25 percent of the undiluted volume: the top of the range for a strong drink such as a Manhattan or Martini, the bottom for a Negroni, which is already lower in proof. Two bar figures to calibrate against: William Elliott at Maison Premiere uses 1.25 oz / 37 ml of water per Martini and 0.75 oz / 22 ml per Negroni.

For the 1200 ml Negroni batch: 20 percent is 240 ml of water. For 12 Manhattans (1080 ml), 25 percent is 270 ml. Pour it in, cap, and invert the bottle a few times.

Before you commit a liter, test one glass: build a single serving, add 0.5 oz / 15 ml of water, chill it in the freezer for an hour, and taste it beside a stirred one. Adjust the water up or down before scaling.

Step 4: chill

Refrigerate at least four hours, or freeze. A batch at 25 to 30 percent alcohol will not freeze in a home freezer; it turns thick and pours like cold syrup, which is the point. Punch's experts set the freezer between 10 and 14 F (minus 12 to minus 10 C). If the bottle shows ice crystals, the batch is too low in alcohol for the freezer and belongs in the fridge instead.

Step 5: label

Every bottle gets tape with: the drink, the date made, the number of servings, the pour size (for these three, 3.5 oz / 105 ml including the water), and the words "contains alcohol" if it will sit anywhere near a kitchen. Add any allergen: vermouth and most wine-based ingredients contain sulfites, and a milk-washed batch contains dairy.

Step 6: serve

Pour straight from the bottle into a chilled glass, or over a single large cube for a drink that will sit a while. The Negroni over a 2 inch cube with an orange peel; the Manhattan up in a chilled coupe with a cherry. No stirring needed.

What never goes in the bottle

• Fresh citrus. Lemon and lime juice start to taste flat within hours and turn bitter within a day. For a Daiquiri or a Whiskey Sour crowd, batch the spirit and syrup, keep the juice in a separate jug squeezed that afternoon, and shake each round to order, or combine the two jugs no more than two hours before service and keep the mix on ice.
• Carbonation. Soda, tonic, prosecco and ginger beer go flat the moment they meet a large volume. Batch everything else, pour the still base into the glass, and top each drink from a cold, fresh bottle. An Aperol Spritz or French 75 is finished glass by glass.
• Egg white and cream. They need a hard shake on the spot and they spoil; see our dry shake tutorial.
• Muddled herbs and fruit. They brown and go bitter in a bottle.

What can go wrong

• The batch tastes watery. Too much water, or wet ice added at service on top of pre-dilution. Use the low end of the range for drinks served on the rocks, because the cube keeps diluting.
• The batch tastes hot and harsh. Not enough water, or it was served warm. Chill longer; a cold drink reads smoother.
• Sediment or haze in the bottle. Vermouth throws a little sediment when cold; fine. Citrus or herb debris means the batch is on its way out.
• The freezer bottle cracked. Glass filled to the brim with a low-alcohol batch. Leave headspace and keep batches below about 20 percent alcohol in the fridge, not the freezer.
• Bitters took over. Scaled in a straight line. Start lower next time.

Responsible service

A batch pours fast and generously, and nobody watches a bottle the way a bartender watches a jigger. Pour a measured 3.5 oz / 105 ml, keep water and food within reach, and set the bottle aside between rounds. Opened vermouth keeps in the fridge for about a month, so a batch built on an old bottle tastes old. Please enjoy responsibly.

Sources

• Punch, "The essential guide to batching and freezing cocktails".
• Death and Co, "How to batch cocktails for a crowd".
• VinePair, "How to batch cocktails at home".
• Simon Difford, "Some cocktails benefit from added water", Difford's Guide.
• Dave Arnold, "Cocktail Science in General: Part 2 of 2", Cooking Issues, 2010.