Provided, That
Provided, That the class or type thereof shall not be deemed to be altered:
(i) Where such wine (other than grape wine) is derived from fruit or other agricultural products having a high normal acidity, if the total solids content is not more than 22 grams per 100 cubic centimeters and the content of natural acid is not less than 7.69 grams per liter, and
(ii) Where such wine is derived exclusively from fruit or other agricultural products the normal acidity of which is 20 parts or more per thousand, if the volume of the resulting product has been increased not more than 60 percent by the addition of sugar and water solution for the sole purpose of correcting natural deficiencies due to such acidity and (except in the case of such wine when produced from fruit or berries other than grapes) there is stated as part of the class and type designation the phrase “Made with over 35 percent sugar solution.”
(c) Nothing in this section shall preclude the treatment of wine of any class or type in the manner hereinafter specified, provided such treatment does not result in the alteration of the class or type of the wine under the provisions of paragraph (b) of this section.
(1) Treatment with filtering equipment, and with fining or sterilizing agents.
(2) Treatment with pasteurization as necessary to perfect the wines to commercial standards in accordance with acceptable cellar practice but only in such a manner and to such an extent as not to change the basic composition of the wine nor to eliminate any of its characteristic elements.
(3) Treatment with refrigeration as necessary to perfect the wine to commercial standards in accordance with acceptable cellar practice but only in such a manner and to such an extent as not to change the basic composition of the wine nor to eliminate any of its characteristic elements.
(4) Treatment with methods and materials to the minimum extent necessary to correct cloudiness, precipitation, or abnormal color, odor, or flavor developing in wine.
(5) Treatment with constituents naturally present in the kind of fruit or other agricultural product from which the wine is produced for the purpose of correcting deficiencies of these constituents, but only to the extent that such constituents would be present in normal wines of the same class or type not so treated.
(6) Treatment of any class or type of wine involving the use of volatile fruit-flavor concentrates in the manner provided in section 5382 of the Internal Revenue Code.
(7) Notwithstanding the provisions of § 4.21(b) (1), (2) and (4), (c), (d)(4), (e)(5), and (f)(6) carbon dioxide may be used to maintain counterpressure during the transfer of finished sparkling wines from (i) bulk processing tanks to bottles, or (ii) bottle to bottle: Provided, That the carbon dioxide content of the wine shall not be increased by more than 0.009 gm. per 100 ml. during the transfer operation.