That Dangerous Chemical Used to Make Your Soft Baked Pretzel

Soft Pretzels


If you enjoy the occasional big, soft and chewy pretzel, you’re not alone. A carnival and shopping mall favorite, there’s even a fast food chain specializing in pretzels.

But if you’ve ever tried to replicate the look, taste, and mouthfeel of these jumbo pretzels at home, chances are you have failed. That’s because of a secret ingredient used in commercial establishments, but not at home. It is a dangerous chemical that can cause severe burns, blindness, and other agony.

This chemical is called caustic soda, or by other names, lye or sodium hydroxide. It is highly corrosive and used mostly in industrial settings to clean machinery, pulping wood, and dissolving some types of metal.

Why in the world would we want this in our food? Well, technically it is not present in the pretzels when you eat them. But, by dipping the pretzel dough in a water solution with a small amount of lye and then baking them, the resulting crust is crisp and unmatchable.The baking process rids the pretzel of the chemical.

  • Realfoodmama

    Are you going to warn people of the dangers of hominy grits next? This article is stupid.

  • allison

    Why are you warning us, if the baking process rids it of the chemical? Am I missing something here?

  • Jake T

    Thanks for the information. Never knew about caustic soda.

  • Sharon Puett

    I agree Allison.
    While on one hand, I like the Fooducate page/app, I am becoming increasingly annoyed with the alarmist headlines and threads.
    Using lye to cure foods (olives, to reduce bitterness) is a centuries old process.
    And lest we forget, lye is also used to make soap (sodium hydroxide for bar soap and potassium hydroxide for liquid soap.) including organic Castile soap which is one of the best, purest multi-purpose cleaners available. What, we should all stop using soap now?
    Really, junk posts like this one make me want to delete the app off my phone, unlike the page and unsubscribe from Fooducate’s emails.

    • Alison Chan

      Also, KOH or NaOH are used in the production of lutefisk, a scandinavian delicacy.

    • Flora R

      As a chemistry graduate student, things like this really get me frustrated. This is one of the typical concentration matters scenarios added with lack of researching food chemistry. Most sodium hydroxide/lye/caustic soda/ascarite/white caustic/sodium hydrate (fyi, all the same thing) that is used to cure foods is VERY mild. For pretzels, its below 3%. However, while making soap, the staring point is usually around 30% and can go as high as 50%.

      In both cases, chemical reactions render the lye harmless. While making soap, all the harmful effects of a the very strong base are removed as saponification (a chemical reaction between oils and the sodium hydroxide) occurs. Similarly, after pretzels are sprayed/dunked in lye, they are baked and a chemical reaction between carbon dioxide in the oven and the very small amount of lye also render the mild base harmless.

      No need to get scared here! Also so called lye-free methods that just use a different alkali metal (i.e. potassium hydroxide instead of sodium hydroxide) still use a very strong base. But because its “lye-free” (sodium hydroxide), people dont get as scared, which is crazy because they are both very strong bases, and should be used with proper caution in their solution form in the kitchen!

  • Ron

    @FOODUCATE and/or @Hemi Weingarten – Can you follow up on the points Sharon Puett and allison posted? I think they bring up good points (though I did not verify), but I’d rather not be “scared” for no reason.

  • Fooducate

    To our readers that are already familiar with lye – thanks for your comments. For those who aren’t, we thought this article would be interesting to read.

    We’re always happy to correct any factual mistakes our community members find on this blog. That does not seem to be the case today.

    We won’t argue with you over style, headlines, or content decisions. It is what it is. If you have suggestions for topics you’d like to see covered here, please email us at blog at fooducate dot com.


    • Ron

      Thanks for the response and keeping things factual. But as a LOYAL Fooducate FAN, how about adding a link near the bottom of the article that says “To find out more info about Lye, click to the Fooducate Lye page, or link to wikipedia.”. Fooducate IS in my mind THE place to go to be educated about food and how its processed. Please always keep things educational. Adding a more info link at the end of the article would generate even more clicks/page views per user visit :-)

      • Fooducate

        Thanks for the suggestion!

  • Tara

    When I worked at the pretzel store in the mall we just used regular baking soda and water to dip them in. I use the same trick at home and they taste great.

  • SeaKat

    Has anyone ever burned themselves with lye? Or inhaled the fumes? Handling lye is not something to be done casually.

    When making soap, an actual chemical reaction takes place changing the lye. Until that change has taken place, lye can still be dangerous.

    • Jody Sue Pratt

      Yes it can be dangerous and that is why soapers wear protective gear to protect themselves— in cold process soap- your oils and lye and any other ingredients you are adding are mixed and put into a mold(wearing PPE) then the full sapification process takes about 48 hours in most cases– in HOT process — same as before mix it all up(in order– lye is always added to the liquid(water, milk tea whatever first- liquid is not added to lye)– but then the entire mixture is heated(i use a crock pot-I have 2 one for food one for soap) and it goes thru several stages then the entire sapification process is done— it is SOAP before you even pour it.. All soaps need to CURe- To evaporate water- turn to a more milder soap- to increase lather etc..6-8 weeks at least— Melt and pour soap bases are sold in hibby stores have already had the lye added and people don’t have to deal with lye personally..

  • LG1

    The site is called Fooducate (or simply, educating readers about food)- I appreciate the knowledge I have gained with the articles. I don’t feel the post initiated any sense of alarm.

  • Someone

    As long as the baking process gets rid of it I’m fine with pretzels.

  • Sara Thompson

    Food Grade Lye is actually quite easy to purchase for use at home. It’s not even overly expensive/

    • Jody Sue Pratt

      LOL you are just highly monitors because people use it for other things– that are not good– so you get on a FED watch list by buying in bulk-if you make soap— interesting article about dissolving people and making soap from people was going around a few days ago– happened a LONG time ago.. hoping it never happens again.. It is easy and inexpensive– Love to make soap here…But respect it for what it CAN do!

  • Kate H

    Hominy is also made with lye, with no ill effects that I’m aware of. Besides Aunt Annies, Wetzels is another popular pretzel chain.

  • wdshendock

    My son bought pretzels in Berlin nj and after eating one he got severe burning in his mouth and throat , that was two days ago and it has only gotten worse. He called the store and the manager admitted that the lye solution was mad too strong by a new employee ! my son may now end up in the hospital !

  • Alamir

    Lye’s only effect is to higher the pH. It it by no means toxic, and certainly not at these concentrations. In addition, it is used in countless processes in the food and other industries. This article is stupid and pointless. You could worry about the amount of salt and fat in a pretzel, though.

  • E W

    Vinegar neutralizes bases like lye. The hydroxide ion is what makes Lye work in “eating” materials. Really, hospitals and common folk can save themselves quite a bit of time WASTED in stopping the chemical reaction (and resulting damage) by applying or ingesting weak acids like vinegar or citric acid if lye goes where it is not intended.