The next morning....
Strain the kvass mixture, squishing the liquid out of the bread cubes.
Add 1/8 cup sugar and 1/8 cup sourdough starter.
Mix well and leave to ferment for 2 to 3 days.
I tasted the mixture at this point - it was sweet and sour at the same time. Very interesting.... I am looking forward to tasting the end result of this experiment.
Kvass: Part I