The Complete Handbook of Marshmallows

Chapter 1: Understanding Marshmallows

At its most fundamental, a marshmallow is a foam: a stabilized suspension of gas bubbles within a continuous matrix of sugar and water. While it is sold and consumed as a candy, understanding it as a structural material is the only reliable way to predict how it will behave when you cut it, melt it, coat it, or store it for two weeks in a warehouse. A marshmallow is not a homogenous solid. It is a network of sugar syrup that is aerated with microscopic air bubbles, and the physical properties of that network are what define its performance in every application.

The core components of this foam are simple. Typically, the base is a hot syrup made from sucrose (standard table sugar) and a glucose syrup. The glucose syrup, often called corn syrup, is not a sweetener but a structural additive. It is a mixture of shorter and longer glucose chains, most critically dextrose, maltose, and higher saccharides. Its primary function is to disrupt the crystallization of sucrose. If a marshmallow were made from sucrose alone, it would rapidly convert into a grainy, highly unstable crystalline mass. The glucose syrup creates a smooth, amorphous, and glassy matrix with a much lower viscosity and a more stable structure over time.

The second essential component is the aerating agent. In traditional marshmallows, this is gelatin. Protein-based gelatin molecules denature and unfold in the hot syrup and form a loose network of chains. When the syrup is whipped,