Cold Brew Coffee Slush for Ninja Slushy Maker Mocha Frappe

Ingredient Spotlight

Cold brew concentrate (room-temperature; reserve a small portion and freeze the rest into cubes)

Cold-brew concentrate is coffee steeped in cold or room-temperature water for many hours to extract a strong, low-acid concentrate that’s usually diluted before drinking. It’s a product of modern specialty-coffee methods (popularized in Japan and the U.S. third-wave coffee movement) and tastes smoother and less bitter than hot-brewed coffee, with chocolatey, nutty notes. You can buy bottled concentrates at coffee shops and grocery specialty aisles or make it at home; a quick substitute is very strong hot-brewed coffee or a shot of espresso diluted and chilled.

Ingredient Spotlight

Sweetened condensed milk

Sweetened condensed milk is cow’s milk evaporated and sweetened into a thick, syrupy canned product widely used in Latin American, Southeast Asian and European desserts. It’s intensely sweet and milky with a caramelizable, slightly cooked-milk aroma. Find it in the baking aisle or in Latin/Asian markets; you can approximate it by dissolving granulated sugar into evaporated milk (or use store-bought dulce de leche or canned coconut condensed milk for a dairy-free option).

Ingredient Spotlight

Xanthan gum (optional, a small pinch stabilizes texture)

Xanthan gum is a microbial-fermentation–derived polysaccharide used as a powerful thickener and stabilizer in gluten-free baking and many processed foods. It’s essentially flavorless but can give a slippery or slightly gummy mouthfeel if overused; a tiny pinch is enough to stabilize cold emulsions. You’ll find it in the baking/gluten-free section or online; common substitutes are guar gum (use roughly 1:1) or, for simple thickening at room temperature, a small amount of cornstarch or arrowroot (these don’t work as well cold).