(a) Effervescent wine may be made on bonded wine premises. Where the effervescence results from fermentation of the wine within a closed container, the wine is classified and taxed as sparkling wine or as hard cider, as applicable. In such wine, the use of carbon dioxide, nitrogen gas, or a combination of both, is permitted to maintain counterpressure during transfer and bottling. Wine carbonated by injection of carbon dioxide is classified and taxed as artificially carbonated wine or as hard cider, as applicable. (For wine to be classified and taxed at the hard cider tax rate, it must meet the requirements set forth in § 24.331, including the limitation of not more than 0.64 gram of carbon dioxide per 100 milliliters.)

(b) Effervescent wine and any wine used as a base in the production of effervescent wine may not have an alcohol content in excess of 14 percent by volume. However, wine containing more than 14 percent alcohol by volume may be used in preparing a dosage for finishing effervescent wine.