What's the Difference Between Gelato and Ice Cream?
[Photographs: Robyn Lee, unless otherwise noted]
After “what’s your favorite ice cream?”, the question I get asked the most as an ice cream maker is “what makes gelato different from ice cream?” How does gelato get that soft, elastic texture and slow-to-melt milkiness compared to ice cream’s richer, creamier body?
It comes down to three factors: fat, air, and serving temperature. The more complicated answer? Things aren’t always clear cut: this is food, not phylogeny, so individual recipes can blur the lines between the two. But there are some basic differences to keep in mind.
How Ice Cream Works
Gelato fresh from the churn at Il Laboratorio del Gelato, NYC. [Photograph: Laura Togut]
All ice cream is mostly water, and as water freezes, it forms hard, crunchy ice crystals. Besides great flavor, the ultimate goal of ice cream making is to keep those crystals as small as possible through added ingredients and technique. Here’s how ice cream makers fight crystallization:
- Emulsifying fat into a base (or using already emulsified ingredients, like cream and milk) sticks fat molecules in between water molecules, literally getting in the way of ice as it freezes.
- Sugar also forms a physical barrier to crystallization, just like fat. When dissolved in water, it forms a syrup with a lower freezing point than plain water, and the sweeter a syrup is (i.e. the higher the concentration of sugar), the lower the freezing point becomes. As water starts to freeze in a syrup, the unfrozen water becomes, in effect, a more concentrated syrup. This process continues until you have a bunch of small ice crystals in a sea of syrup so concentrated that it’ll never really freeze.
- Air is incorporated into ice cream during the churning process. Just like a light, fluffy angel food cake is easier to cut into than a dense fruit cake, a more aerated ice cream is easier to scoop, and has a fluffier, less dense texture.
- The temperature ice cream is stored at also has an obvious effect: colder ice creams are harder and more solid, while warmer ones are softer, with a looser texture.
There are some other tricks to keep ice cream soft, such as alcohol, starch, protein (in egg and milk), and natural stabilizers like guar gum and carageenan, but the top four above are the big factors at play.