Recycling of substandard bread, technological waste and bread from the distribution network is a promising way of waste management and raw materials saving. In order to optimize the old bread recycling process and to improve the quality of finished products, a new resource-saving technology for rye–wheat bread was developed. It was found that use under 25% of bread crumbs instead of flour was possible in a liquid sourdough with a moisture content of 70%. When old bread dosage increased from 50 to 100%, acid accumulation slowed down, the lifting force deteriorated, the viscosity increased, which may makes it difficult or impossible to pump the sourdough in industrial technological process. The liquid sourdough made with 25% of old bread had a better lifting capacity and contained more alcohol and volatile acids than the control. The quality of bread made using sourdough with 25% of old bread was comparable in quality to control bread made using traditional sourdough. Liquid rye sourdough with recycled old bread allowed the bread shelf life extension by slowing down the bread staling. No effect on mold rate was found when using recycled old bread in sourdough.