27 C.F.R. § 24.202
In the production of wine from dried fruit, a quantity of water sufficient to restore the moisture content to that of the fresh fruit may be added. If it is desired not to restore the moisture content of the dried fruit to that of the fresh fruit, or if the moisture content is not known, sufficient water may be added to reduce the density to 22 degrees Brix. If the dried fruit liquid after restoration is found to be deficient in sugar, sufficient pure dry sugar may be added to increase the total solids content to 25 degrees Brix. After addition of water to the dried fruit, the resulting liquid may be ameliorated with either water or sugar, or both, in such total volume as may be necessary to reduce the natural fixed acid level of the mixture to a minimum of 5.0 grams per liter; however, in no event may the volume of the ameliorating material exceed 35 percent of the total volume of the ameliorated juice or wine (calculated exclusive of pulp). Pure dry sugar may be used for sweetening. After complete fermentation or complete fermentation and sweetening, the finished product may not have a total solids content that exceeds 35 degrees Brix.
27 C.F.R. §24.202
26 U.S.C. 5387