Baking soda solution for pretzels
Submitted by KitchenBarbaria... on April 30, 2011 at 3:41 am

From cooking science expert Harold McGee, a method of modifying baking soda to get a better pretzel
Source: http://www.curiouscook.com/site/2010/09/achieving-a-distinct-flavor-with...

Baking soda
Just spread a layer of soda on a foil-covered baking sheet and bake it at 250 to 300 degrees for an hour. You’ll lose about a third of the soda’s weight in water and carbon dioxide, but you gain a stronger alkali. Keep baked soda in a tightly sealed jar to prevent it from absorbing moisture from the air. And avoid touching or spilling it. It’s not lye, but it’s strong enough to irritate.

Baked soda is also strong enough to make a good lye substitute for pretzels. In order to get that distinctive flavor and deep brown color, pretzel makers briefly dunk the shaped pieces of raw dough in a lye solution before baking them. Many home recipes replace the lye with baking soda, but the results taste like breadsticks, not pretzels.

Baked soda does a much better job of approximating true lye-dipped pretzels. Just dissolve 2/3 cup (about 100 grams) in 2 cups of water, immerse the formed raw pretzels in this solution for three to four minutes, rinse off the excess dipping solution in a large bowl of plain water, and bake.

Excerpted from the NY Times; see the originating link for more detailed information
NY TIMES link