Today I'm revealing my secret to party planning: the easiest way to serve cocktails to a crowd. Batching up cocktails in advance provides you, as the party host, a way to offer guests well-made cocktails, but frees you up to otherwise enjoy the party, and not feel compelled to make drinks to order. It's a win-win.
How and Why to Bottle a Cocktail
The idea is simple: Instead of making cocktails one at a time, I suggest that you make up a bunch of servings of your favorite cocktails (in bottles or pitchers) in advance before your guests arrive. Keep them well chilled, and you can either serve them yourself or allow guests to help themselves.
One option is to decide on a signature cocktail, prepare it in advance, and have it prechilled. As guests arrive, you greet each one with a glass of your signature cocktail, poured straight from the bottle. No fuss, and everyone can move on to having a good time, host included. After the first drink, you can serve more premade cocktails, or move on to wine or beer. Even if you decide to hire a bartender for your party, you may want to ensure the drinks are all good by mixing up the recipe in advance.
Now, let's take note of a couple of things before we begin.
How Far In Advance?
If your batched cocktails will include fruit juice, you need to prepare them the day of the party. Juice is volatile and goes bad quickly. You might get away with batching up your cocktail the night before, but no earlier.
If your drink has no fruit juice or other fresh ingredients, you're fine. You can batch it up days in advance; just be sure to keep it in the refrigerator, especially if it contains vermouth, which is a wine-based ingredient that oxidizes if left at room temperature.
The Role of Water
Water is an essential ingredient in a cocktail. It softens the flavor of the drink and rounds out the rough edges of the spirit. Ordinarily, you add water to a cocktail as you prepare it, in the form of ice: as you stir or shake a drink, the ice melts and both dilutes and chills the cocktail. A well-made cocktail will be about one fifth to one quarter water.
So you can add water to your batched cocktail in two different ways. One option is to mix up the batch and then when it's time to serve the cocktail, stir or shake it over ice just before serving.
But I think it's better to add the right amount of water in advance and then keep the cocktail very well chilled. This makes it easier if guests are serving themselves—all they need do is pour. This also means you can be sure the water in the cocktail is tasty (whether that's straight from your tap or filtered) and you won't taint your drink with off flavors from storebought ice.
Batching requires some simple math in advance, but hey, I'm going to do that for you!
All you'll need to do at party time is chill the batched cocktail very well and serve—or let guests serve themselves.
What You Need
First, get bottles or lidded pitchers. These don't need to be fancy—empty wine or liquor bottles would work—but it's a party, so it's fun to class it up a bit and get a few swing-top glass bottles.
My recipes are based on making 32 ounces in each batch, so each bottle serves 8 four-ounce cocktails. Swing-tops in this capacity can be found in stores and online; in a pinch, you can reuse 1L wine or liquor bottles.
You might want a separate bottle or pitcher for mixing the batch, but it's not necessary—you can mix each batch directly in the bottle that you'll pour the cocktails from.
What you will need, though, is a measuring cup. I'll be providing volumes in ounces, so you might find it helpful to have a clear plastic angled measuring cup, like this one.
Finally, a funnel will certainly make your life easier, so grab one of those while you're at it.
Before we go to the recipes, just a hint of theory first. (Yawning? You can skip ahead to the recipes.)
With regard to martinis, I love a ratio of 3 or 4 parts gin to 1 part vermouth. Here, to make the math easier, I've used a 4:1 ratio. Your batch is going to be 32 ounces, and water will fill up about one fifth of the batch, or 6 ounces. So your gin and vermouth together should fill 26 ounces. Your gin-to-vermouth ratio is up to you, if you want to tinker—just make sure it totals 26 ounces. If you're going with 4 to 1, that's 20 ounces of gin and 6 ounces of vermouth.
Manhattan: I'm assuming a classic ratio of 2 parts rye to 1 part sweet vermouth.
Margarita/Sidecar/Sour: The ratio is 3 parts spirit (tequila, cognac, whiskey) to 2 parts triple sec and 1 part citrus juice.
Proportions are up to you, so long as they equal about 26 ounces before you add the water. The water shouldn't be adjusted much, though—it's necessary in order to mimic the dilution that would happen with stirring or shaking, and to give the cocktail its proper balance and bring out the flavors in the alcohol. Plus, it's just responsible. Though a boozier cocktail might sound fun in theory, but it'll liquor up your guests all the faster, and at some point, they need to find a way home, unless you're very generous and you're hosting them for the night.