Commentary for Avodah Zarah 147:11

R. Nahman distinguishes between yayin nesekh, wine which we know was libated, and ordinary wine belonging to gentiles. With the former, the halakhah follows R. Shimon b. Gamaliel only when casks are mixed up. But when it comes to ordinary wine, the rule is always lenient. The mixture may be sold minus whatever amount of yayin nesekh was part of the mixture.