Abstract: The invention relates to a heat transfer liquid which comprises 2 to 12 parts by weight of water, at most 4 parts by weight of urea and/or formamide and/or dimethyl formamide, at most 7 parts by weight of ammonium nitrate and optionally ethylene glycol at most of the same volume than that of the above-listed components as major components with at most 0.3% by weight or by volume of corrosion inhibitors calculated for the total weight or volume of the liquid.Using the heat transfer liquid of the invention the drawbacks derived from the application of glycol can be completely or in most part eliminated and a non-toxic heat-transfer liquid suitable for isopiestic drying can be also prepared.