Gelato differs from ice cream in that it has a lower butterfat content, typically gelato contains 4-8% versus 14% for ice cream. Gelato generally has slightly lower sugar content, averaging between 16-22% versus approximately 21% for ice cream. Non-fat milk is added as a solid. The sugar content in gelato is precisely balanced with the water content to act as an anti-freeze, that is, to prevent the gelato from freezing solid. The types of sugar used are sucrose and dextrose and invert sugar to control the apparent sweetness. Typically, gelato and Italian sorbet contain a stabilizing base. Egg yolks are used in yellow custard-based gelato flavors, including zabaione and creme caramel.