Baking Soda and Baking Powder:
The pH of baking soda (not baking powder, but ordinary carbonate of sodium) is somewhere between 8 and 9, depending on this and that. So it is slightly basic. On the other hand, how it alters the pH of a dish in which it's an ingredient is complicated because baking soda is a buffer. Not to whine, but doesn't really seem fair to have other hands and complications in something which should be as unambiguous as cooking chemistry
The most common form of single acting baking powder is a combination of sodium carbonate (baking soda) and potassium bitartrate (cream of tartar). Potassium bitartrate is acidic; that is, it has a low pH. The usual ratio for baking powder is two parts cream of tartar to one part soda. When the baking powder is mixed into solution, the cream of tartar creates a sufficiently acidic environment for the carbon dioxide to separate from the sodium in the bicarb, create bubbles, and thereby lighten the pancakes or whatever. In short, baking powder is essentially baking soda with its own acid.
You can make your own single acting baking powder quite easily if you follow the simple ratio. Will it taste fresher, better? Try it and see.
Double acting baking powder adds a second source of acid which actively reacts with the source of carbon dioxide with (sufficient) heat.
As far as I know, neither baking powder nor baking soda do anything to facilitate browning of any sort, including the Maillard reaction.
A Potato Pancake By Any Other Name:
Potato pancakes are a popular part of nearly every Northern European cuisine, there's nothing especially German about them... but there's nothing especially not German either. There are traditional variations, for instance the use of olive oil Berndy wrote about, but those don't seem to belong to any particular country. The biggest distinction is between pancakes made with grated or ground potatoes and, in my experience, you tend to see ground batter as a more high-end, i.e., economic presentation than regional. For instance, if I were making potato pancakes to serve with caviar as an app, I'd use ground.
For the little it's worth, I use double acting baking powder in my recipes. As several other people have said it adds loft and creates an airier texture.
I can see the benefit of the bake ahead and then fry method for high volume, but not for ordinary household or high-end restaurant use. It is a way of getting a crisp outside texture and preventing them from absorbing too much grease; but results in a mealy pancake, which is something I don't favor. It's a compromise you have to make sometimes, at large Hanukkah parties for instance, but one best avoided if possible.
All in all, the most important step in making good potato pancakes of any sort is getting all the "potato water" out of the gratings. That's true whether you're going to make the batter from gratings or go one step further and grind (or puree) them.
Here is one of my recipes along with some -- well, a lot -- of thoughts. The result is a very light pancake; at least as "light" as those things go.
Potato pancakes, smoked salmon and caviar make an excellent app for a romantic dinner. And champagne. Did I mention champagne?
Happy Valentine's Day,
Edited by boar_d_laze - 2/17/13 at 10:44am