I am the son of a retail baker who retired in 1965. I believe that it was in his shop, so this is an old memory, that Dad told me that one needs to be very careful about the amount of baking soda in a cookie formula because it is a determining factor in the spread of a cookie. I believe that at the time he was talking about ‘lunch box’ cookies, i.e., oatmeal, chocolate chip, ginger molasses, etc.
I tried a Google search to confirm this, but it is not easy to construct one that does not deliver many false positives or no answers at all. Has anyone seen this phenomenon explained by gurus like Harold McGee or Shirley Corriher?
I was recently baking biscottini and confirmed the phenomenon to my satisfaction. When I was done, I was mildly put off by the residual taste from the soda, (1/4 tsp, rounded, per 3/4 cup of flour.) It led me to ask the question, are there alternative ingredients that would promote spread. I use one basic dough recipe and vary the flavoring ingredients. I’ve always noticed that if I use melted chocolate the loaves spread more. Perhaps it is the fat content in the chocolate?
Does the soda function as a leavening agent here? Would ammonium bicarbonate work as well? It should leave no residue as it disproportionates into ammonia and carbon dioxide, both gases which would bake out in a hot oven. There remains the question of whether or not it would promote spread. It does not seem to do so in my springerli formula, which uses quite a bit.
For reference, here is an example of the biscottini formula (I am open to suggestions regarding formatting columns):
as fxn as oz
0.38 cup sugar (2.75 oz) 3/8 2.75
0.25 stick unsalted butter, room temperature 1/4 1
0.5 egg large eggs, beaten 1/2
0.5 tsp grated dried orange peel (softened in warm brandy) 1/2
0.25 tsp baking soda (use a rounded tsp full) 1/4
0.13 tsp salt 1/8
0.75 cup all purpose flour 3/4
0.31 cup hazelnuts, toasted, husked, coarsely chopped 5/16 1.
0.22 cup dried tart pie cherries, chopped and softened in brandy 7/32 1.06
0.19 lb bittersweet or semisweet chocolate 3/16 3
0.13 tsp vanilla
0.13 tsp rum, and a few drops of rose water to taste
All batches were ½ egg batches - use a ‘full’ 2 cl shot glass full per batch ~ 25 ml if your large eggs are ~50 ml. Beat the egg and add the vanilla, rum, and rose water to it. One can mix several eggs and add proportionate amounts of flavor to them to simplify the measuring. For the record, vanilla/rum/rose is the flavor that says ‘bakery’ when you smell it.
Slicing – start with a ‘wavy’ serrated knife and finish with a razor sharp knife – steel it regularly
For those biscottini which are chocolate, I used 3 oz of melted Guittard L’Etoile du Premiere 58% pastilles.
Every batch was flavored with 2 heads (dried) of English lavender, ground in a mortar with 0.125 t of salt, with 0.25 t of cinnamon and anise seed powder and 0.125 t of mace added at the end. Each was also flavored with 0.5 tsp of dried Trovita orange peel softened with hot brandy.
Pay attention to the protocol, cream sugar and butter, mix in eggs carefully, mix in the spices, mix in half of the flour, add the fruit and nuts (be careful to exclude any excess brandy used to soften the fruit) and mix then add the rest of the flour and knead lightly
Position 1 rack in center of oven and preheat to 325 F. Beat sugar and butter until well blended. Beat in egg just until blended. Mix in orange peel, baking soda and salt and spices. Add ½ of the flour, and the hazelnuts and dried cherries; stir until well blended. Add remaining flour, stirring until well incorporated. Knead until it can be rolled. Divide the dough into 3 equal portions. Start a rolled log by hand and then finish it by rolling it between a 4” wide piece of wood and the countertop until it is the length of a cookie sheet. Bake on parchment. Bake 15 - 20 minutes at 325 F, or until the top of the loaf is firm to the touch. Remove to a cooling rack for 10 minutes. Using long wide spatula, transfer the logs to a cutting board. Using a razor sharp knife, cut the warm logs crosswise into 1/2-inch-thick slices. Arrange the slices cut side down on 2 baking sheets. Bake them for 10 minutes. Turn them over and bake bake them again until light golden, about 10 minutes longer. Transfer to a rack and cool completely. They are especially nice if they are coated at one end with a wipe of molten Guittard L’Etoile du Premiere 58%.
Here are the additional varieties I made for Christmas 2010: Azteca (sliced almond, Zante currants, smoke dried Habañero and jalapeño chiles or chipotles - be careful) in the chocolate base, Britannica (pine nuts and quadruple English lavender), pine nut and chopped candied lemon peel, dried pear with pistachio nuts and candied ginger, Bing cherry with hazelnuts, and candied lemon peel and sliced almond with chopped chocolate pastilles.