Combine yeast, warm water and sugar with pinch of salt in a dish and leave to foam for 5 minutes. Sift flour and remaining salt in a medium bowl. Add yeast mixture and 3/4 cup water and stir until everything comes together. Knead on a lightly floured surface until smooth.
Place in a slightly oiled bowl and turn to coat, cover with plastic wrap and leave to rise for 1 hour.
Dissolve baking soda in 1 cup cold water. Preheat oven to 400°F.
Punch down dough and cut into 8 pieces. Roll out each piece until approximately 18 inches long and twist into a pretzel shape. Dip pretzel into baking soda mixture and place on parchment covered baking sheet. Sprinkle with coarse salt if desired. Repeat with remaining pretzels.