I'm looking at highly rated bagel recipes. I'm surprised that many (if not most) of the recipes call for sugar in the water the bagels are boiled in instead of baking soda. That has me a bit puzzled. I always thought that the water is supposed to be alkaline, like lye in the water in old-fashioned pretzel recipes, that it is the alkalinity of the water that give bagels (and soft pretzels) their distinctive chewy texture. What am I missing? Will sugar really create that texture?
The main purpose of adding things to the boil are to promote browning and flavor. The texture of the crust is more a product of gelatinizing the starches by boiling, using a high oven temp, and using a good amount of steam during baking.
You can increase browning two main ways, by promoting the Maillard reaction and/or promoting caramelization. Baking soda, lye, or sodium carbonate baths increase the Maillard reaction, and increase surface gelatinization by breaking down some starch, but also give the bagels a "pretzely" taste. You can also promote the Maillard reaction by adding protein to the surface by using an egg or milk wash. Sugar (white or dark), honey, and malt added either to the boil and/or the dough increase surface caramelization and also lend a subtle glaze.
Personally, I always use malt incorporated both into the dough and into the boil. It adds a subtle sweetness and cereal flavor that complements the bagels. I find the pretzel taste from an alkaline bath off-putting. When I don't have malt I use honey, molasses, or brown sugar. I don't use an egg wash either, if you want to add toppings just place the bagel into the topping right out of the boil... they'll stick without anything else.
baking soda (or even better, baked baking soda...see:
is commonly used at home to make soft pretzels. I would use sugar, unless you want that distinctive pretzel flavor for your bagels.
I think that maybe the sugar is what gives the bagels their delightful glaze once they are baked. I don't know, have never used anything but sugar when dunking my bagel dough! Haven't made them in awhile though.... do you brush on some beaten egg before sprinkling them with your toppings or not? Hmm.... anyway, my bagels always turned out good with sugar in the water.
I did make raisin bagels for the first time too, and i had them boiled in baking soda and sugar water even though recipe called for malt syrup or honey, and I had neither. (I had no clue at that time why I was boiling the slightly risen dough and now I know.) Then i brushed them with a canola oil (or avocado or any other mild oil will do) with a pastry brush. Figured that egg or oil would give the same effect. I do think that the chewy taste came from the sugared and baking soda water boiling, and the glaze by the brushed on oil and helped by the surface created by boiling.