I’ve been putting alcohol into seltzer for a while now, which is why the sudden popularity of hard seltzer caught me by surprise. Any seltzer can be hardened by the addition of booze, but pouring a shot into a can of Polar or La Croix isn’t going to make it taste like a White Claw. You can, however, get pretty close by adding a little bit of sugar.
You see, unlike “innocent” seltzers, spiked seltzer contains a little bit of sugar—about a gram—just enough to take the edge off the ethanol. Armed with this knowledge, there’s no reason you can’t replicate the effects at home (using the alcohol you already own), and you can switch up the liquor. Since we’re aiming for an ABV of around 6%, you’ll need one and a quarter ounces of 80 proof booze, along with half a teaspoon of simple syrup. If you want to up the flavor factor, shake some bitters in there. (Though I love Polar and La Croix, I have to admit they taste like you’re looking at a fruit real hard while sipping on seltzer.) You can even build it right in the can. To make your own hard seltzer, you will need:
1 8-ounce can of your favorite seltzer
1 1/4 ounces of 40 proof liquor (Vodka is the most adaptable)
1/2 teaspoon of simple syrup (Make a small amount in a mug)
Bitters to taste (Fruit-flavored bitters work best)
Open the can of seltzer and pour an ounce and a quarter out. Drink it. Mix the syrup in with the liquor, then slowly funnel it into the can. Give the contents of the can a stir with a straw, and take a sip. If you want more than a whisper of fruit flavor, add some grapefruit, lime, cranberry, or grapefruit bitters.
Link:https://skillet.lifehacker.com/how-to-make-your-own-spiked