For this you need a 5 – 6 quart non-metal container. Put bran and corn meal in. Add yeast (or solid leftovers from previous batch of borsh).
On top of this, add boiling or very hot water to the top. After it cools off, add one sliced lemon (with peel), oregano as well as the bread. Then, mix this concoction every morning and evening with a long-handled wooden utensil. Taste it after a few days, and if it is sour enough, place container in a cool place so that the liquid clears. The solid stuff will sink to the bottom. Then put the clear liquid in bottles and keep them in a cool place.
The solids are to be kept in the same container and after you finish the borsh in the bottles, you can start again. You only add boiling water on top of it. Note: Don't leave the clear borsh to sit on the solids or it will turn bitter.