What is baking soda bath?

A boiling water bath with baking soda dissolved in it, used to give pretzels their signature dark mahogany crust and chewy bite. Standard ratio is ½ cup baking soda per 8 cups water. Briefly simmering shaped pretzels in the alkaline bath (30 seconds per side) gelatinizes the surface starches, which produces the distinctive sheen and chew. The bath's alkalinity is the key — boiling water alone won't give pretzels their character. Boiling the baking soda for a few minutes before adding the pretzels increases the alkalinity (~10× more, as bicarbonate partially converts to sodium carbonate), producing even darker, more flavorful crusts. Commercial pretzel makers use food-grade lye (1-4%), which is much more alkaline still — baking soda is the safe home equivalent.