OAK-BASED EXTRACT PRODUCTION TECHNIQUE Russian patent published in 1995 - IPC

FIELD: wine production. SUBSTANCE: a not less than 80-years old trunk of oak tree is stored in the natural conditions for 6 months until its moisture content reaches about 20 percent. Then its top and the part distanced about 40-50 cm from its butt end are sawed away. Then the trunk is chopped into chips in two stages: first it is chopped into 2-3 cm chips and after into 1.0-1.5 cm chips. With the chopping finished, the mass is subjected to extraction at the temperature of 110-115 C and pressure of 3 atm for 5-6 hours in a block of successive order diffusers. From diffusers number 2,3 and 4 diffusion juice is taken to be evaporated to obtain liquid extract. The extract obtained is thickened until its moisture content reaches 18-20 percent; then it is dried up to a 6-8 moisture percent. EFFECT: higher efficiency.