Andrea Slonecker, author of Pretzel Making at Home, says when it comes to the invention of the pretzel, "we don't know really what's true." She shares the pretzel's origin story and how to make the iconic snack at home.
The invention of the pretzel
David Leite: Pretzels are so ubiquitous here in America, but of course they have a very rich and foreign history. How did it all begin? How did it get here to America?
Andrea Slonecker: It's believed that they were invented in the year 610 by monks along the Mediterranean, somewhere where Italy and France now meet. It's believed that they were first invented as little rewards for children for learning their prayers. A monk tore off a piece of dough, shaped it into this twist that was meant to represent a child's arms crossed over his chest in prayer (which is how people would have prayed back then), and gave it to the children if they learned the scripture.
There is another plausible theory, though -- there's a lot of folklore and a lot of legends. We don't know really what's true, but another theory is that pretzels were sustenance for monks during the Lenten fast. The three holes in the pretzel were meant to represent the holy trinity.
Pretzels came to America in the 19th century with the Dutch immigrants who settled in Pennsylvania. Pennsylvanians eat 12 times as many pretzels as the rest of the country. I did go there to research the book of course for that very reason. They have a lot of pretzel bakeries in Pennsylvania. The Italian immigrants in Philadelphia adopted this curious bread that they had never seen. They started baking them in Philadelphia and selling them on street corners.
Hard pretzels were invented in America in the Pennsylvania Dutch country when a young apprentice baker forgot a batch of pretzels in the oven overnight. The ovens went cold, but the pretzels remained in there and hardened overnight. The baker decided to try selling them the next day. Thus, America’s favorite snack food was invented.
DL: How did this interest in home pretzel making start?
Pretzel Making at Home
AS: About 5 years ago, I began seeing pretzels on menus at various restaurants around the country. They were in artisan bakeries being used as the sandwich bread. I really was curious about why I started seeing it everywhere. I started researching pretzels. That led me to start tinkering in my kitchen with baking them myself.
What really makes it a pretzel I think is the fact that it's dipped in an alkaline solution before baking. That's what gives it that really amazing crust, that characteristic flavor, that leathery texture and that dark color that we expect with a pretzel.
DL: Traditionally in Germany they use lye, which is an alkaline solution that can be caustic. But you found a very ingenious way of substituting that.
AS: I was really lucky at the time that I started researching pretzels. The amazing food scientist Harold McGee had just come out with an article in The New York Times about how to basically create a substance that is similar to lye in your home kitchen, but not quite as caustic and much more readily available. That is by taking baking soda, spreading it out on a baking pan and putting it into the oven at about 250-300 degrees Fahrenheit for about an hour. That changes the chemical properties in the baking soda to make it behave more similarly to lye. [Ed. note: More on Slonecker's technique here.]
Slonecker's recipe:Pennsylvania Dutch Hard Pretzels
DL: After the baking soda comes out of the oven and it cools, what do you do with it to make the pretzels?
AS: You begin with the dough. You shape it into that iconic shape, then you dip it in an alkaline solution (the baked baking soda and water). It's a small percentage of baking soda to water. You dip the pretzels into the solution, put them on a baking sheet, pop them in the oven and then you have freshly made pretzels.
In Germany they come in knots, sticks, rolls, twists and all sorts of different shapes that are used for making sandwiches or just for eating with butter at breakfast. Even in America I've seen croissants dipped in a lye solution and baked or pretzel pigs in a blanket. You can come up with all sorts of different pretzelized creations.
That is by taking baking soda, spreading it out on a baking pan and putting it into the oven at about 250-300 degrees Fahrenheit for about an hour. That changes the chemical properties in the baking soda to make it behave more similarly to lye.
The most benign substitute for lye is baking soda. You'll get a little bit of browning and some chew, but don't expect it to taste very pretzel-y. You can also used baked baking soda, which is a stronger alkali than baking soda but not as caustic as lye.
Lye has a pH of around 13 whereas baking soda has a pH of around 8. This extra alkalinity accelerates the Maillard reaction, allowing that caramelization to develop on the exterior of the pretzels. That ultra deep color and slightly crispy, crunchy exterior crust is only made possible with lye.
Lye is a stronger alkaline than baking soda or sodium bicarbonate, with a pH reading ranging from around 13 to 14. Its base of sodium hydroxide is created commercially by the electrolysis of sodium chloride solution, as well as reacting calcium hydroxide with sodium carbonate, according to the FDA.
In this method, you're replacing lye with baking soda, both of which are alkalies. However, lye is much stronger than baking soda. Heating up baking soda in the oven turns it from sodium bicarbonate into sodium carbonate, making it a slightly stronger alkali that'll better replace the lye.
The main way that you can make soap without handling lye is by using melt-and-pour soap. The part of it that's real soap has already been through saponification (oils reacting with lye) and is safe to use and handle straight out of the package.
While straight baking soda works OK, using baked baking soda will help you achieve a richer, deeper color and better texture without having to use food-grade lye. To make pretzels with baked baking soda, simply swap it 1:1 for regular baking soda in your favorite soft pretzel recipe.
Dipping the dough in a lye solution gives traditional German pretzels their characteristic salinity; chew; and smooth mahogany exterior, but the strong alkali (sodium hydroxide) is corrosive and can burn your skin, so it must be handled with caution.
Well, the cheery ladies were very clear with me: they do NOT use lye. No sodium hydroxide/poison/caustic soda—none whatsoever—in their pretzels. (They do, however, dip their pretzels in a baking soda solution.) So there you have it.
In a deep bowl, wearing rubber or latex gloves, make a solution of ½ cup lye and 10 cups water (or 1 part lye to 20 parts water); pour lye carefully into water to avoid splashing. Dip each pretzel in solution, turning it over for 10 to 15 seconds, and place back on baking sheet. Sprinkle pretzels with salt.
To prepare a lye bath for pretzels, fill a large liquid measuring cup with four cups of cold water.Add the water to a heavy, plastic container and carefully mix with two tablespoons of food-grade lye until fully dissolved.
It's very easy, and inexpensive, to prepare a homemade version as a substitute. You only need two ingredients for homemade lye water: Baked baking soda and water. Mix them at a 1:4 ratio. Then you're ready to use it!
Caustic soda is sodium hydroxide which is lye - they are the exact same thing; just different names. The reason behind the different names is mainly to do with the chemical name being “sodium hydrate” and the chemical itself is “caustic or corrosive”, leading to being known as caustic soda.
This is usually glycerine – a natural product of saponification – so they are basically adding something that was created using lye, but they do not add the lye themselves to avoid having to say they use it. In the end, you are not getting lye on your skin in either case.
Lye is a strong alkaline product used to make soaps and cleaning products and in the chemical industry. It comes in two forms, caustic soda and caustic potash. Caustic soda is sodium hydroxide with the chemical formula NaOH and caustic potash is potassium hydroxide with the chemical formula KOH.
The dipping stage normally takes just 10-15 seconds of exposure to the hot alkaline solution which is about 200°F. Traditionally the solution was a mixture of sodium hydroxide and water. Today, most production involves the use of sodium carbonate and bicarbonate solutions which are not as caustic as NaOH.
Since you can't really find lye at the grocery store, you can use a baking soda bath to get the same results. The chemical reaction takes place in the baking soda bath, and after baking in the hot oven you'll get that beautiful brown crust that pretzels are so famous for.
Like lye, baking soda is an alkaline substance, and when mixed with water and brushed over the pretzel dough, it changes the pH of the dough and gelates the surface starch. In the oven, the starch gel hardens and the alkaline baking soda makes browning happen fast.
Introduction: My name is Corie Satterfield, I am a fancy, perfect, spotless, quaint, fantastic, funny, lucky person who loves writing and wants to share my knowledge and understanding with you.
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Andrea Slonecker Photo: David Reamer 
Pretzel Making at Home 
Slonecker's recipe:Pennsylvania Dutch Hard Pretzels 