When it’s 10 p.m. and the grass is still steaming, you need something tropical and clean to revive you, without the hard work of a frozen froufrou drink. A straightforward grown-up cocktail is in order.

Infused vodkas are simple, require a minimum of planning, and far outshine the shelves of flavored vodkas available. Two of the best and most versatile are ginger-infused and grapefruit-infused.

For the ginger infusion, peel and slice a 2- to 3-inch piece of fresh ginger into chunks and submerge it in a 750-milliter bottle of your favorite vodka. Place in the refrigerator and let sit 4-5 days, shaking occasionally.

To infuse the grapefruit flavor, carefully peel the rind from an entire grapefruit with a vegetable peeler (impress your friends and family by doing so in one continuous piece — you’ll have to point this out to them frequently), and proceed as above.

How to drink it? Ice-cold and neat — that’s the best way. Or you can get fancy:

Lime-Ginger Martini (serves one)

2 ounces of ginger vodka

Juice of 1 lime

1 teaspoon of simple sugar syrup

Shake ingredients with ice and strain into glass. Garnish with a lime twist.

Grapefruit and Blood-Orange Cocktail (serves one)

2 ounces of grapefruit vodka

Scant « ounce of Cointreau or triple sec

Splash of blood-orange juice

Splash of sparkling water

Shake vodka, Cointreau and juice together with ice and strain into glass. Top with a splash of sparkling (carbonated) water. Garnish with an orange slice.