Crisped rice is a processed rice product. Typically, manufacturers sell it as a breakfast cereal or add it to sweets, such as chocolate candy bars or crispy rice bars. There are a few ways to process the rice grains, including a process called gun puffing. Gun puffing produces a softer, puffier product than baking or frying the prepared rice grains. Most people buy crisped rice cereal to use as a cereal or in cooking, but there are recipes available for homemade crisped rice.
Making crisped rice is similar to making popcorn out of corn kernels or making puffed wheat. The starchy grains pop or puff up when the moisture inside heats up quickly. Popcorn naturally has a high moisture content, which facilitates the process. Rice is a much drier grain; therefore, the first step to making crispy rice is to introduce moisture into the rice grains.
Generally, commercial food processors increase the rice's moisture content by steaming the grains. Recipes for home cooks frequently suggest cooking the rice and then drying it in a medium hot oven. The oven baking dries the surface of the rice while leaving the internal moisture intact. Introducing the moisture-laden rice grains to high heat creates the popping process.
Home cooks usually fry the prepared rice in hot oil to bring the sudden and drastic temperature change required to quickly expand the trapped moisture and enact the puffing process. Commercial food companies use hot oil or hot ovens. Another process, called gun puffing, creates a softer puffed rice product. Food processors accomplish this by pressurizing the moisture-laden rice grains and then quickly releasing the pressure, which puffs the grain.
One of the attractions of the crisped rice is the noise it makes when immersed in a liquid. It reacts, making a crackling or snapping noise. It is a complex process, whereas the dried, altered grains of starchy rise have shrunk unevenly in the drying or puffing process. The uneven surfaces create a stress within the piece of rice. As the liquid rehydrates it quickly, it creates more stress and makes a crackling noise.
Food manufacturers and home cooks use crispy rice in recipes. One of the most popular foods is breakfast cereal. Many candy manufacturers add the crisped rice into chocolate bars to add a crunchy, light texture to the chocolate. One of the most popular domestic recipes creates a snack bar using the rice, a marshmallow product or corn syrup, and butter or oleomargarine. This recipe is popular because the limited amount of liquid and the coating of the marshmallow or corn syrup preserves the crunchy texture of the crisped rice.