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The 3 Best Cocktails To Put in a Flask

The 3 Best Cocktails To Put in a Flask

Flasks are perfect for whiskey and other straight spirits. But sometimes you want something that brings different flavors and a lower ABV. Enter the flask cocktail.

When it comes to times that it’d be nice to have a cocktail in a flask, I’m thinking first of weddings. There are plenty of other events you might want to have something on hand to sip on (tailgates, backyard barbecues, movie dates, and outdoor concerts, for example), but weddings are the main one where it’ll be socially acceptable and most practical for you to keep slipping your hand into your inside pocket to enjoy the cocktail of your choice that may or may not be outside the confines of what the wedding bar can offer.

Before you go pouring whatever you just shook up into your flask, keep in mind it’s not as straightforward as pouring a spirit in there. There’s a whole lot of flavor reasons why cocktails are served cold, and any metal container sitting next to your body for a period of time will be decidedly not cold. (So yes, Martinis are out.) Fresh citrus also doesn’t do so well as it sits around and gets warm and increasingly less fresh–and if your flask is aluminum instead of 100-percent steel, the acidity in citrus could cause aluminum to leech into your drink.

You will, however, still want to stir or shake your cocktail before you put it in the flask, otherwise you miss out on that all-important dilution.

There’s also the issue of cleanliness. Flasks have smaller openings and tighter, wider insides than you can reliably clean with a brush. That’s not usually a problem, since most of the straight alcohol you’re putting into it is itself extremely unfriendly to any kind of mold or grime that might otherwise grow on a drinking vessel. Under normal circumstances, the interior of a flask only really needs a good rinse with hot water, and maybe a quick pass with a soapy sponge over the mouth, before you can confidently throw it back into circulation.

A cocktail is a different story. Even all-spirit cocktails use a sweetened liqueur. Putting a cocktail in the flask introduces sugar, drastically increasing the risk of mold or sticky buildup. It’s not an immediate danger or even one that’s all that high stakes or unsolvable. Rinsing it out right away, or even the next day or two, with soap and warm water will solve most of your issues.

It’s a small ask for the joy of having a homemade cocktail in your pocket if you know the right drinks to put inside.

Recipes are scaled to fit inside an eight-ounce flask, though the exact proportions may need to be played with a bit to fit your specific flask.

The Best Cocktails To Put In a Flask

Old Fashioned

Old Fashioned

I’m going to trust that the average Cool Material reader will know what I’m talking about when I say that sometimes, in very limited situations, occasionally, bourbon might, just maybe, be a little tough to drink. If only for the reasons that it can absolutely destroy your breath and those of us who are single might find that a bit of a handicap at one of these flaskable events. Putting an Old Fashioned in your flask still keeps your cred as a bourbon drinker (or rye drinker if you prefer the traditional rye Old Fashioned over a bourbon Old Fashioned). It just has the benefit of also rounding out the edges of what might make an extended bourbon session tougher to handle. It’s also one of the most customizable cocktails out there, so you can match it to your preferences with any number of solid Old Fashioned variations.

Flask Old Fashioned recipe:

  • 4 ounces bourbon or rye whiskey
  • 2 ounces simple syrup
  • 4 dashes Angostura bitters

Stir all ingredients with ice to dilute, then pour into your flask.



The Sazerac is a classic American cocktail. It is the official cocktail of New Orleans and was named after a brand of Cognac (the original recipe calls for brandy, but rye whiskey is more common now). It’s similar to an Old Fashioned, but with a stronger flavor thanks to the absinthe rinse.

Flask Sazerac recipe

  • 4 ounces rye whiskey
  • 1 ounce absinthe
  • 2 ounces simple syrup
  • 2 dashes Peychaud’s bitters

Stir all ingredients with ice except for the absinthe. Pour the absinthe into your flask, swirl it around to give a good rinse, and then dump it. Pour the cocktail into your flask.

warday's cocktail

Warday’s Cocktail

Warday’s Cocktail is like a gateway cocktail for people who want to get more into gin but are a little reluctant to leave the big flavors of barrel-aged spirits behind. Calvados is the traditional brandy of choice, but in a pinch any apple brandy will do. The drink is on the dry and herbal side like a boozy gin cocktail, but the apple brandy and sweet vermouth do enough to make it tangential to a Manhattan.

Flask Warday’s Cocktail recipe

  • 2 1/4 ounces gin
  • 2 1/4 ounces sweet vermouth
  • 2 1/4 ounces Calvados or other apple brandy
  • 3 dashes Yellow Chartreuse

Add all ingredients into a cocktail shaker. Shake until the outside is frosty, then strain into your flask.

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