Fining /(?)/

Fin·ing

Fining

n.
  1. The act of imposing a fin.
  2. The process of fining or refining; clarification; also (Metal.), the conversion of cast iron into suitable for puddling, in a hearth or charcoal fire. (Metal.)
  3. That which is used to refine; especially, a preparation of isinglass, gelatin, etc., for clarifying beer.

Phrases & Compounds
Fining pot
a vessel in which metals are refined.