Standard wine other than citrus wine, regardless of the fixed acid level, may be stabilized as a part of the finishing process by the addition of citric acid within the limitations of § 24.246 . Standard wine (including citrus wine) may be stabilized by the addition of fumaric acid within the limitations of § 24.246 .
27 C.F.R. §24.244
Sec. 201, Pub. L. 85-859, 72 Stat. 1383, as amended ( 26 U.S.C. 5382 )