As if on cue, my good friend Gerhard writes in from Vienna to say:
I have one question about the cookie recipe… it features baking soda, but no acids (like vinegar, lemon juice, sour milk products etc.blablablah). How will that one work… you write that brown sugar is acidic?
btw: Chocolate Chips are unknown here. We use big bars of baker’s chocolate, which is a very low quality version of chocolate that contains a lot more sugar. Nothing semi-sweet here… except the high-quality chocolates for Gourmets.
I remember living in Britain, way back when, and hearing tales of other American students in Europe whose families would send them bags of chocolate chips in the mail. As far as I know, it’s not impossible to find chocolate chips on the Continent (Nestlé claims to serve a chip market there), just very difficult.
As far as the leavening question goes, brown sugar is indeed acidic. Not the sugar itself, but the molasses that the brown sugar contains. It’s acidic enough to react with the the full teaspoon of soda without leaving a “soapy” alkaline taste behind.