While most sour cream is gluten-free, the best sour creams are ones made with only cultured milk or cream and enzymes. Some brands will add fillers, like modified corn starch, guar gum, and carrageenan, to make the sour cream thick. These ingredients are not needed to make a good sour cream. The best brands of gluten-free sour cream are Daisy, Cabot, and Organic Valley.