Buyers must distinguish between the three main types: Kappa, Iota, and Lambda. Kappa carrageenan forms strong, rigid gels in the presence of potassium ions, making it ideal for meat processing and firm dairy products. Iota carrageenan forms elastic, freeze-thaw stable gels with calcium, perfect for puddings and creamy textures. Lambda carrageenan does not gel but acts as a high-efficiency thickener for instant beverages and sauces. Always specify the refined vs. semi-refined grade; refined is clearer and used for high-end food/pharma, while semi-refined is cost-effective for pet food or industrial use.