Bring the water to a boil, you can divide it into two parts. Cut the bread into pieces and fry in a dry pan until black.
Remove water from the heat and add raisins and whole bread. Cover the container and leave overnight.
Mix sugar with yeast. Remove the bread from the pan and add sugar to the water. Cover the pan with foil and leave for another 6 hours, stir every 2 hours. Then strain the kvass through cheesecloth.
Bottle, seal tightly and refrigerate. Let stand in the refrigerator for 2-3 days.
Have a nice drink !!!