Why Using Lye Is Key to Making German Pretzels | Cook's Illustrated (2024)

Pretzels have been depicted in religious art since at least the Middle Ages, when monks supposedly twisted bread dough scraps to form pious shapes: The gaps between the strands represented the Holy Trinity, and the crisscrossed ropes represented arms folded in prayer. They were also Lent friendly, free of animal products such as eggs and butter that the medieval church forbade during the spring fast, and they occasionally show up in medieval renderings of the Last Supper.

But at Freiburger Münster, the medieval cathedral in Freiburg, Germany, pretzels were incorporated into the stained glass windows lining the nave for a more secular reason: They promoted the bakers guild that helped fund their construction. The twists are prominently displayed in a coat of arms alongside windows with equally glorious emblems of beer pitchers for the brewers, boots for the cobblers, and scissors for the tailors. Devout donations, with a side of advertisem*nt.

“When you go into town, and you’re feeling snack-y, you get a buttered pretzel,” he told me on a video call from his home in Brighton, England.

Lest Krauss’s recollection inspire visions of pallid, floppy, butter-slicked twists from a mall food court, let me be clear: The German pretzel is a more noble beast, as revered in its home country as the baguette is in France. Maybe it’s the alluring chestnut exterior, with that satiny sheen and pretzel-specific mineral-y tang, all results of a quick alkaline bath before baking. Maybe it’s the fine yet satisfyingly chewy crumb. Maybe it’s the versatility: Pair a pretzel with sausage and mustard for breakfast as they do in Munich, enjoy a few with beer, or slice one horizontally and fill it with meat and cheese or simply smear it with butter.

Dunking dough into a strong alkali such as lye is an admittedly curious thing to do, and there are theories as to how this process came about—including one of a baker who mistakenly brushed his pretzel with cleaning fluid and decided to just go with it. But the base agent’s impact on the dough is actually terrific: It boosts flavorful browning by accelerating Maillardization and caramelizing sugars in the dough. It imparts that unique pretzel smell and taste by inhibiting the creation of typical baked-good aroma compounds while spurring the formation of others and also adds unmistakable mineral flavor. And it gels surface starch, so the pretzels bake up smooth and shiny.

The stronger the alkali, the more intense and impressive the results, which is why German bakers use lye; it features a chart-topping pH of 14and produces the ultimate pretzel experience. (Rest assured, you’re not ingesting a dangerous chemical: The oven’s heat completely neutralizes lye and makes it safe to consume.) That said, if sourcing and handling lye isn’t for you, you can use a simmering baking soda solution instead. With a pH of roughly 8.3, it reacts less than lye and yields pretzels that are lighter in color and flavor, but the results are still impressive.

An alkaline bath is what makes a pretzel a pretzel and not just a tanned twist of dough. The base reacts with proteins, sugars, and starches at the pretzel’s surface to intensify browning and give the skin its tight, glossy sheen. It also imparts that saline, mineral flavor.

A simmering baking soda solution is a pantry-friendly option with a moderately high pH that encourages ample browning and pretzel-y flavor. All you do is dissolve ½ cup of baking soda in 8 cups of water, bring the solution to a boil, lower it to a simmer (heating the solution makes it more reactive and effective), and briefly dunk each pretzel in it. Then you salt and bake the pretzels.

After making an inverted U with the dough rope, forming the twist is simple.

1. Cross rope ends once, andthen again.
2. Lift ends and attach them to curve of inverted U at about 10o’clockand 2o’clock. Press ends firmly into body of pretzel.

But if you want the genuine article, you have to do as German bakers do and dip the dough in a room-temperature, food-safe lye solution. (The native name, Laugenbrezel, means “lye pretzel.”) It’s the strongest alkali, and its color, flavor, and textural impact on the dough is simply unmatched. Fifteen seconds in a lye bath plus a hot bake equals deeply bronzed, distinctly saline pretzels that shine like polished mahogany.

Of course, lye is caustic stuff that can burn your skin and discolor surfaces, so it’s important to approach the dipping process with respect and caution. So before baking Ipored over lye safety documents and consulted with our senior science research editor, Paul Adams, to work out safety best practices. Idonned some stout latex gloves and safety goggles and then carefully mixed 40grams of lye crystals into 1,000grams of cold water until the crystals dissolved. (Starting with cold water is important because lye raises the temperature of the solution when it dissolves.) Itransferred each pretzel individually to the bath, let it hang out for 15seconds, and then drained it on a wire rack. Imoved the drained pretzels to a baking sheet, sprinkled them with pretzel salt (a coarse, slow-melting salt), and slid them into the oven.

The surface of these twists was dark, lustrous, and smooth around the plush, chewy crumb. Ibit into one and immediately recognized that characteristic mineral flavor. It was all the convincing Ineeded that lye is worth the effort—and, frankly, once Ihad my dipping station and safety practices in order, working with lye was quicker and simpler than the simmering baking soda dip. (But don’t pass on pretzel making because you’re not comfortable using lye; the baking soda treatment produces perfectly acceptable results, and I’ve included directions for both.)

It’s often said that the German language has a word for everything. The one that came to mind as Isettled down with a pretzel, which I’d buttered liberally in Jürgen’s honor, was “wunderbar.”