Furcellaran is extracted raw seaweed Furcellaria lumbricalis and the liquid extract is purified by filtration. The liquid extract may be converted into flaky furcellaran by evaporation of water to yield by drum drying. Proper release of the dried material from the dryer roll requires addition of a small amount of roll-stripping agents (foo doil).
Also the furcellaran can be isolated from the liquid extract by precipitation of the furcellaran with potassium chloride. This process gives pure and concentrated product.