HARD PACK is a frozen mix of cream or milk, sugar, and (sometimes, as in the case of our custard-based recipes) egg that’s been vigorously agitated, or “churned,” to introduce air. The mixture is then frozen and served at subzero temps.
SOFT SERVE skips the deep freeze; it’s sold directly from a churning and cooling machine and served at around 20°F, much warmer than hard pack.
GELATO really just means “ice cream” in Italian. But it’s churned more slowly than American ice cream, giving it a dense, gooey texture. And more milk in the mix means gelato has lower butterfat—4 to 8 percent compared to 10 to 20 percent in hard pack stateside.
FROZEN YOGURT starts out as cultured milk, a.k.a. yogurt, and is then flavored and churned like any ice cream. Fro-yo has a lower fat content than hard pack (since no cream is used), plus a yogurty tang.
SHERBET is made from fruit flavoring, water, and sugar mixed with only a tiny bit of dairy (cream, milk, buttermilk, or egg whites) for low butterfat content, 1 or 2 percent.
SORBET is a dairy-free mixture of fruit, water, and sugar (and much less air, since water and juice lack the fat globules that trap air inside dairy-based blends).