Bentonite
The short version
A natural smectite clay — the standard wine fining agent and a clarifier for fruit juices.
It's widely considered safe at the amounts used in food, so we mark it green. The Safety section below has the details.
Where it comes from
A naturally occurring clay formed by weathering of volcanic ash. The dominant world source is Wyoming, USA. The active mineral is montmorillonite, with characteristic swelling between layered aluminosilicate sheets.
How it's used
The classical wine fining agent — adsorbs proteins, polyphenols, and color, then settles out for filtration. Also used for fruit-juice clarification, edible-oil refining (bleaching), and as a binding agent in some supplements. Outside food, common in litter, drilling muds, and as a digestive supplement (sometimes controversially marketed).
Safety profile
ADI not specified — considered safe at typical use levels (residue in finished beverage is essentially zero). Bentonite is filtered out after the fining step. Naturally contains trace heavy metals, so food-grade material must meet purity criteria.
Physical & chemical properties
Off-white to gray fine powder. Swells dramatically in water (3–20× initial volume). Strong adsorption capacity for polar molecules and small proteins.
Regulation worldwide
Permitted globally without restrictive limits.
Educational information only. Not medical or dietary advice.