Summertime is the season for cooling jellies, and one of the most popular kinds in Japan is kanten. Overseas, this is known as agar-agar, but here kanten and agar are confusingly considered to be two distinctly different substances.
Three types of gelling agents are commonly used in the Japanese kitchen: gelatin, agar and kanten. Both agar and kanten are derived from seaweed, and neither, unlike gelatin, will dissolve at room temperature. And since they are both vegetable-based, they are ideal for vegans and vegetarians — unlike gelatin, which is derived from animal-based collagen.
The main difference between the two is the texture. Agar-based jelly has a wobbly, soft, gelatin-like texture and "mouthfeel" — not surprisingly, since it is specifically manufactured to resemble gelatin. Agar is made with carrageenans, a family of polysaccharides derived from various red seaweeds including Irish moss, and locust bean gum, which gives it its texture.