Pretzels, whether soft and chewy, hard and crunchy, salted, sweet, or gluten free, all have the same distinct deep brown color. But how is this deep pretzel color achieved? If all the ingredients are the same as traditional white bread, what gives pretzels their unique color and flavor? The answer, simply stated, is a chemical process called the maillard reaction.
Pretzel dough is made quite similarly to regular bread dough, using water, flour, yeast, sugar, butter, and salt. The ingredients are first mixed together, then the dough is kneaded, and finally left to rest while the yeast goes to work rising the dough. Once the dough has risen, it is rolled and shaped into the classic pretzel twist shape. However, unlike regular bread, before baking, the pretzels undergo a special step. This step is to boil the shaped pretzel dough in a high alkaline, or basic, solution. This may seem like an odd process if one does not understand why it needs to take place, as stated by Culbertson, “As I started reading recipes, I came across a cooking technique I have never applied in my kitchen – boiling the bread dough in baking soda before baking. But why?!” (2017 p.1) But as she later discovers, “It turns out this step plays an important role in a process called the Maillard reaction.” (Culbertson 2017 p. 1) The reaction, discovered by French chemist Louis Maillard in the early 1910’s, can be defined as “...a heat-activated reaction between small sugars and amino acids.” (Friedrich 2014 p. 1) Dipping the dough into a alkaline bath such as lye or baking soda “...alters the ratio between sugar and protein, because lye breaks proteins present in the dough into smaller bits.” (Friedrich 2014 p. 1) These “smaller bits” being the small amino acid chains, which then join with the sugars in the dough, and ultimately undergo the maillard reaction when placed under heat. This combination of amino acids and sugars in the pretzel dough are what “...create the flavor compounds at the pretzel's crust.” (Friedrich 2014 p. 1) The result is a golden brown, richly flavored pretzel, that could not have been created without the wonder of the maillard reaction.
References
Culbertson, S. (2017). Making Pretzel Buns And The Maillard Reaction. Scibertson.
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Friedrich, P. (2014). For a Proper Pretzel Crust, Count on Chemistry and Memories. NPR.
-pretzel-crust-count-on-chemistry-and-memories.
