In large bowl, stir yeast, sugar and warm water. For about 5 minutes, let mixture rest until yeast is dissolved and foamy. Then add salt and mix in flour. Knead until smooth and elastic. If dough is not stiff enough, add more flour.
Place in oiled bowl. Cover and let rise until doubled in size. Portion into 77 g pieces, roll each 35 cm (14 inch) long ropes, and shape into pretzels.
Fill pot with 4 1/2 cups water (1 Liter). Add baking soda. Heat water in pot to where it is almost boiling.
Preheat oven to 215C (420 F) and bring water to boil when ready to cook pretzels. Drop each, one or two at a time into a large pot of boiling water, boiling each for no more than about 15 seconds each, taking care to fully submerge each pretzel. Place on plate.
Prepare a parchment paper lined baking pan or pizza stone. Brush each pretzel with egg wash (1 egg beaten mixed with 1 tablespoon water), and then sprinkle with kosher salt. Bake in oven for 12-15 minutes.