Instructions for baked baking soda. To bake baking soda, spread it out on a small baking dish and place in a 250 degree oven for 1 hour. The heat of the oven chemically alters the baking soda to make it behave similarly to lye. It will keep indefinitely in a covered container at room temperature.

Instructions for the pretzels:

In the bowl of a stand mixer or in a large mixing bowl, dissolve the yeast in the warm water. Stir in the barley malt syrup and set aside to bloom until foamy, 5 to 7 minutes. Add the flour, beer, butter and salt and stir. Begin kneading on medium-low speed, or by hand on an un-floured work surface. After about 1 minute the dough will form a ball. It should be quite firm and may be slightly tacky, but not sticky. (If it is sticky, add more flour, 1 tablespoon at a time. If it's too dry to come together, add more water, 1 teaspoon at a time.) Continue kneading on medium-low speed until smooth and elastic, 5 to 7 minutes.

Put the dough in a large bowl that has been lightly greased with butter. Cover the bowl tightly with plastic wrap and place in the refrigerator to rise for at least 8 hours, and up to 24 hours, for optimal flavor.

Line two 12-by-17-inch baking sheets with parchment paper; set aside. Turn the dough out onto an un-floured work surface and firmly press down to deflate. Cut into 8 equal portions. Work with 1 portion at a time and keep the rest covered with a damp cloth. Pat the piece of dough down to form a rough rectangle. Beginning on a long side, roll the dough up tightly, forming a little loaf. Pinch the seam together. Shape the dough into a rope by rolling it against the work surface with your palms and applying mild pressure, working from the center of the dough out to the ends. If you need more friction, spray the counter with a little water from a squirt bottle or drizzle a few drops of water and spread it with your hand. Once you can feel that the dough rope doesn't want to stretch any farther (usually when it is between 12 to 16 inches long), set it aside to rest and begin shaping another piece in the same manner. Repeat this process with the remaining pieces of dough.

Return to the first dough rope and continue rolling it out to a length of 24 to 28 inches, leaving the center about 1 inch in diameter and thinly tapering the ends by applying a little more pressure as you work your way out. Position the rope into a U shape, with the ends pointing away from you. Holding an end in each hand, cross the ends about 3 inches from the tips and then cross them again. Fold the ends down and press the tips into the U at about 4 and 8 o'clock. Place the pretzel on one of the prepared baking sheets and cover with a damp cloth. Repeat this process with the remaining dough, spacing the pretzels at least 1 inch apart.

Allow the covered pretzels to rise at warm room temperature until increased in size by half, about 30 minutes. (The pretzels can be refrigerated at this point, with the whole tray covered tightly with plastic wrap, for up to 8 hours before dipping and baking them.)

Position one rack in the upper third and another rack in the lower third of the oven and preheat it to 500 degrees. Wearing rubber gloves, put the lye or baked baking soda in the bottom of a wide, shallow stainless-steel pot and fill it with 6 cups of water. (Avoid nonstick and other metal surfaces, such as aluminum and copper, which will react with the lye. Be careful not to splash the alkaline solution on your skin or eyes.) With the hood vent on high, warm the solution over high heat just until you see wisps of steam, and then carefully remove the pan from the heat and wait until the steam subsides. While the solution is still hot, use a large skimmer to dip the pretzels, one or two at a time. Soak for about 20 seconds, carefully turning once after 10 seconds. Lift the pretzels from the solution, drain off excess liquid and return them to the baking sheets, spacing at least 1 inch apart. Repeat with the remaining pretzels. If using baked baking soda, lightly brush the pretzels with the egg mixture. Sprinkle generously with salt.