Rev. Rul. 66-173

Polyvinylpolypyrrolidone (known as PVPP), an insoluble homopolymer of purified vinylpyrrolidone meeting the requirements of 21 CFR 121.1110, may be used within the general limitations of 26 CFR 240.524 as a clarifying and stabilizing agent in the cellar treatment of wine in amounts not to exceed six pounds per 1,000 gallons of wine, followed by removal of the material with filtration.

Winemakers desiring to use this material in the treatment of wine may obtain approval of the Assistant Regional Commissioner, Alcohol and Tobacco Tax, by filing notice pursuant to the provisions of 26 CFR 240.1052.

Revenue Ruling 65-137, C.B. 1965-1, 590, which restricted the use of Polyvinylpolypyrrolidone to 2 pounds per 1,000 gallons of wine is hereby superseded.