Put carrots, ginger, and orange peel into a half-gallon jar.
Add salt and whey and fill the remainder of the jar with water, leaving a 1-inch headspace.
Cover tightly with a lid, and shake well to dissolve the salt in the whey and water.
Remove canning lid and cover with a clean towel or coffee filter.
Secure with a rubber band or canning ring.
Place in a warm spot to ferment for 2 to 4 days, depending on temperature.
The longer it ferments, the more sour it will get. Begin to taste after the first two days and allow to ferment to your liking.
Strain the liquid from the carrots, leaving about 1 cup of liquid in the jar for another round of kvass. To make a second, weaker batch of kvass simply add water and repeat fermentation instructions as above.