Dissolve first
Sift 2 grams of matcha into a small vessel and add 30 to 40 milliliters of cool or room temperature water. Whisk or shake until completely smooth before adding ice or more water. Ice-cold water tends to leave the powder floating in clumps.
Cold shake versus pour over ice
For a cold shake, combine the dissolved matcha base, more cold water, and ice in a sealed shaker and shake hard for 10 to 15 seconds for a light foam. For a quieter pour, dissolve the matcha in a little water, fill a glass with ice, and add cold water or milk on top.
Sweeteners
If you sweeten, add a small amount of simple syrup or honey to the dissolved base before topping with ice, since granulated sugar will not dissolve in cold liquid. Many shops use a 1 to 2 teaspoon syrup pour for a 12 ounce iced drink, but plain iced matcha from a clean drinking grade tin needs nothing added.