(a) General. Still wines may contain not more than 0.392 gram of carbon dioxide per 100 milliliters of wine; except that a tolerance to this maximum limitation, not to exceed 0.009 gram of carbon dioxide per 100 milliliters of wine, will be allowed where the amount of carbon dioxide in excess of 0.392 gram per 100 milliliters of wine was due to mechanical variations which could not be completely controlled under good commercial practices. Such tolerance will not be allowed where it is found that the limitation of 0.392 gram of carbon dioxide per 100 milliliters of wine is continuously or intentionally exceeded, or where the variation results from the use of methods or equipment not in accord with good commercial practices.

(b) Notice required. Proprietors intending to add carbon dioxide to, or retain carbon dioxide in, still wines to be shipped to the United States shall submit a notice to the appropriate TTB officer. The notice shall show the name and address of the proprietor and shall identify the method or process, the kinds (class and type) of wine, and the type of equipment to be used. A corrected notice shall be filed if there is any change (except for minor changes) in the information contained in the notice.

(c) Filing and disposition of notice. The notice required by paragraph (b) of this section shall be submitted in quadruplicate to the appropriate TTB officer, who shall retain one copy, forward one copy to the Secretary, and one copy to the revenue agent at the proprietor's premises, and return one copy to the proprietor. The proprietor shall keep the notice available for examination by revenue agents.