6 (1/4-ounce) packages dry yeast

1 and 1/2 cups sugar

2 cups hot water

2 cups seltzer

1/3 cup oil

3 and 1/2 tablespoons kosher salt

4 eggs, plus 1 additional egg yolk, for brushing

1 3-pound bag extra-fine, pre-sifted whole-wheat flour (I use Shibolim; if presifted flour is not available, you can sift it yourself)

1 cup wheat germ

1 and 3/4 cups white flour, such as Glicks

Gefen Sesame Seeds, poppy seeds, or everything spice, for sprinkling (optional)