In a large mixing bowl, combine the warm water, sugar, and yeast. Let it sit for 5 minutes until foamy.
Add the flour, salt, and melted butter. Mix until a dough forms.
Knead the dough for 8–10 minutes until smooth and elastic.
Place the dough in a lightly greased bowl, cover, and let it rest and rise for 1 hour, or until doubled in size.
Preheat the oven to 425°F (220°C) and line two baking sheets with parchment paper.
Bring 8 cups of water to a gentle boil and carefully stir in the baking soda.
Divide the dough into 8 equal pieces and roll each into a rope about 18 inches long. Tie each rope into a knot and tuck the ends underneath.
Boil each pretzel knot in the baking soda bath for 20–30 seconds, then remove with a slotted spoon and place on the prepared baking sheets.
Brush each knot with the egg wash and sprinkle with coarse pretzel salt.
Bake for 15–18 minutes, or until deep golden brown.
Brush the hot pretzel knots with melted butter if desired.
Cool for 5 minutes before serving.