Shellfish and chitosan

We’ve all heard of comments about sulfites or phenolic compounds causing headaches, but I use chitosan and kielsosol for clarifying agents. Chitosan is made from shellfish byproducts — could these cause an allergic reaction (headaches?) to those who are allergic to shrimp or lobster?

Ray Ruthenberg
Woodbine, Illinois

Though I’m no medical doctor (I seem to say that a lot in this column), from what research I was able to pull together, if I personally had a shellfish allergy I would feel comfortable using chitosan products to clarify my wine. I will let you make up your own mind (in conference with your physician of course), but from what I understand, seafood allergies derive from proteins in crustaceans and shellfish, not from materials in their shells.

Chitosan is a manufactured product that is derived from chitin in the shells, a natural polymer. During the manufacturing process, the shells only (no fleshy protein bits) are used, and any protein that could possibly be clinging is removed.

Chitosan is a great flocculating agent in wines. It precipitates solids and is a very efficient clearing agent — basically you add it to your wine, it gloms on to solids and then falls out of solution to the bottom of your container. If you rack cleanly enough (which means giving the solids plenty of time to settle) you should be able to leave the chitosan fining agent, plus the tannins and wine proteins it pulled out, behind in your container.