1Place the warm water in the bowl of a stand mixer and sprinkle the yeast on top. Set aside until the yeast has dissolved and the mixture is slightly bubbly, about 5 minutes. (If the mixture does not bubble, either the water was not at the correct temperature or the yeast is old.) Meanwhile, coat a large mixing bowl with a thin layer of vegetable oil and set aside.
2Place the flour, sugar, and measured salt in a large bowl and whisk briefly to break up any lumps. Once the yeast mixture is ready, dump in the flour mixture, place the bowl on the stand mixer fitted with a dough hook, and mix on the lowest setting until the dough just comes together, about 1 minute. Increase the speed to medium and knead until the dough is elastic and smooth, about 8 minutes.
3Form the dough into a ball, place it in the oiled mixing bowl, and turn to coat in the oil. Cover the bowl with plastic wrap and let the dough rest in a warm place until it doubles in size, about 30 to 35 minutes. Line 2 baking sheets with parchment paper and coat the paper with vegetable oil. Place a piece of plastic wrap (the same length as the baking sheet) over the oil on each sheet and press to coat; set the baking sheets aside.
4Once the dough has risen, punch it down and knead it until it’s smooth and springs back when poked, about 1 minute. Using a dough scraper or knife, divide the dough into 16 equal pieces (about 1 1/2 ounces each). Place the pieces spread apart underneath the plastic wrap on the prepared baking sheets (8 per sheet).
5Working with 1 piece at a time, roll a 16- to 18-inch-long rope. Hold one end of the rope in each hand and cross the two ends. Cross them again to form a twist. Lay the twisted end over the opposite side of the rope and press gently to adhere. Lift up the oiled plastic wrap, transfer the pretzel to the baking sheet, and cover. Repeat with the remaining dough pieces, fitting 8 pretzels per baking sheet.
6Let the pretzels rise in a warm place until almost doubled in volume, about 15 to 20 minutes. Meanwhile, heat the oven to 425°F and arrange a rack in the middle. Bring the 6 cups of water to a boil in a large saucepan over high heat and set 2 wire racks nearby.
7When the pretzels are ready, remove the plastic wrap. Stir the baking soda into the boiling water (the water will foam up) and place 2 pretzels, bottom side down, in the water. Boil for 1 minute, flip using a slotted spoon, and boil 1 minute more. Remove with the slotted spoon and place on one of the wire racks. Repeat with the remaining pretzels.
8Sprinkle the pretzels evenly with salt. Bake 1 sheet at a time, rotating halfway through the baking time, until golden brown, about 8 to 10 minutes. Transfer immediately to a rack to cool.