What Stabilizers Do

• If you've ever watched water beading on the windshield of a car, you'll know it has a tendency to flow together into larger drops and eventually a stream. That process slows when the water is frozen, but it doesn't go away. If you froze sweetened, flavored cream without any stabilizers, it might begin with small and delicate crystals but they'd quickly join together to form larger, granular ice pellets. Stabilizers work much the same way as thickeners in gravy, immobilizing the ice cream's water content and thwarting its natural tendency to make large crystals.

The Traditional Stabilizers

• The original stabilizer for ice cream is egg yolks. The oldest and most canonical recipes for ice cream were made from cooked custards, which heated the sweetened cream until the eggs set and thickened the entire mixture. Then it was churned into a smooth, rich ice cream. Premium brands are still often made this way, but mass-market ice creams often use gelatin instead. It's less expensive and lower in fat and calories than eggs, making the finished product both more profitable and more appealing to fat-conscious dessert lovers. But both eggs and gelatin are animal-derived and pose problems for some diners.

The Case for Non-Animal Stabilizers

• You may want to avoid animal-based stabilizers in ice cream for several reasons. For example, eggs are a common allergen and many people must avoid them. Gelatin typically contains pork, which many avoid for religious reasons. Vegan ice creams, made from nut milks or coconut milk, avoid animal-based stabilizers as a matter of principle.

Seaweed Stabilizers

• Oddly, many of the commonly used stabilizers are derived from seaweeds. A common example is carageenan, derived from a type of seaweed called Irish moss. It's often used to thicken chocolate milk and puddings as well as ice cream. Alginates are another class of seaweed-derived stabilizers, which gel in the presence of calcium. That makes them highly useful with dairy products, such as ice cream, which are high in calcium. A third widely used stabilizer is agar agar, which creates a firm gel that's similar to the gel that gelatin forms though with slightly different characteristics. Agar agar is widely available as a vegan gelatin substitute, and the other two can be ordered from online stores.

Carbohydrate Gums and Cellulose

• Several stabilizers are natural carbohydrate gums, similar to the pectin you use to make jam. Xanthan gum, guar gum and locust bean gum are all widely used in ice creams and many other commercial products such as low-fat salad dressings. Xanthan gum is produced by beneficial bacteria grown on a nutritional medium, while the other two are naturally harvested and plant-based. Some forms of cellulose and hemicellulose -- respectively the material of plant cell walls, and the natural adhesive that holds them together -- are also extracted from numerous sources and used as thickeners. The gums are available at health and bulk food stores, but cellulose thickeners are primarily sold as industrial products.