What Is Sea Moss?

A Guide to Buying and Using Sea Moss

Bowl of Irish Moss (aka Sea Moss)

lmaldris01 / Getty Images

Sea moss, also known as Irish moss or carrageen moss, is a species of red algae that is primarily used to make carrageenan, a thickener and stabilizer commonly used in ice creams and other processed foods. It's often used as a vegan and vegetarian substitute for traditional gelatin, which is made from animal byproducts. 

What Is Sea Moss?

Sea moss (Chondrus crispus) is a dark red plant that grows on rocks along both coasts of the Atlantic ocean. One of its main structural components, making up the cell walls of the plant, is a type of carbohydrate called carrageenan. This carbohydrate, a cellulose, is extracted by boiling the plant, causing it to absorb water and form a jelly. This jelly is in turn used as a thickening and emulsifying ingredient in desserts, yogurts, sauces, salad dressings, pates, and vegetarian hot dogs, to name just a few. 

Because it binds well with proteins, it is especially useful in thickening dairy products, which is why it is so frequently used in making ice cream, cream cheese, and yogurt. It's often used in chocolate milk to keep the cocoa particles from separating from the milk and settling on the bottom of the container. 

Sea moss is just one type of seaweed that contains carrageenan that can be extracted for use in food. 

To extract carrageenan from sea moss, the plant is first cleaned and washed to remove sand and other debris, then it's cooked in a solution of potassium hydroxide, an alkali that helps to strengthen the gel. After another round of washing and drying, the cooked seaweed is ground up finely and then processed with either alcohol or potassium chloride, which dissolves the carrageenan so that it can be extracted. It also undergoes color removal. The concentrated gel is then dried, milled into a powder, and packaged.

Sea moss can be processed in different ways to produce different types of carrageenan, some that are soft and pliable, some that are hard and brittle, and others that don't jell but instead are used as thickeners. 

How to Use Sea Moss

The most common way to use sea moss in the kitchen is in the form of carrageenan powder, which is mainly used to thicken liquids. So for example, if you were making a cheesecake, you might use carrageenan powder instead of gelatin powder. If so, you'd add the carrageenan powder along with the sugar, salt, and other dry ingredients. Next, you'd blend the dry ingredients with the liquid ones, such as the egg yolks, milk, and cream cheese, then blend until smooth, pour the mixture into your pie shell and bake. 

In other cases, you might have to dissolve the carrageenan powder and heat it to form a gel before adding it to your recipe. 

It is also possible to create a gel by cooking dried sea moss, although it will likely retain its seaweed flavor and color, and it may also have a coating of salt from the ocean. 

Carrageen moss
 Efesan / Getty Images
Irish moss
 Ablokhin / Getty Images
Irish moss
 Efesan / Getty Images

What Does It Taste Like?

Sea moss itself has a seaweed-like flavor, but the carrageenan that is extracted from it is flavorless.

Sea Moss Recipes

You could substitute carrageenan made from sea moss in many recipes that call for gelatin.

Where to Buy Sea Moss

Carrageenan is available at specialty food stores and health food stores and online outlets that carry vegan and vegetarian products. Dried sea moss is also available from health food stores and online merchants. 


Dried sea moss will last for a year if kept sealed and stored in a cool, dry place. Carrageenan powder can be stored for a similar amount of time as long as it's sealed and kept cool and dry. If you make a gel from the carrageenan powder, or by cooking the sea moss itself, you should use it right away, although you could store it in the refrigerator for two to three days.