Abbreviation for rectified grape must concentrate. Rectification is a thermal separation process for separating a homogeneous solution of two or more substances by repeated distillation or countercurrent distillation. This results in a concentration of all soluble substances. The result is a product without the caramel taste caused by heating in other processes. It is produced by partial dehydration using various methods. This is also the difference to concentrated grape must. It is mostly produced by vacuum evaporation of grape must at very low temperatures to prevent the undesirable caramel taste (therefore fire heat is obsolete). Production by the chemical process of ion exchange is subject to strict EU regulatory guidelines. A relatively new process is spinning cone column, but this is not permitted within the EU. Wines treated in this way in the USA may, however, be marketed in the EU.