Banana cake (test)

Last time I was baking my banana cake, I realised halfway through that I didn't actually have any baking powder - the packet I thought I had turned out to be baking soda. Now, baking powder is (or at least can be) a mixture of baking soda and an acid, so in order to use baking soda in stead of the baking powder the rest of the ingredients have to be sufficiently acidic. This - as I've understood it - is not merely a question of leavening, but also one of taste. Baking soda in a batter with too little acid might result in a somewhat alkaline taste, which is not desirable in any cake I'm familiar with.

For these reasons it's not given that baking soda can be substituted for baking powder, but then a friend of mine pointed out that bananas are in fact somewhat acidic (as per this list) and therefore the banana cake might work out just fine with baking soda..

Naturally, such an idea had to be tested: are bananas sufficiently acidic to make banana cake using baking soda?

Ingredients:
- 100g (3.5 oz) margarine
- 140 g (5 oz) flour
- ²/₃ tsp baking soda
- 200 g (7 oz) sugar
- 2 tsp vanilla sugar
- 3 eggs
- 2 well-ripened bananas
frosting:
- 100 g (3.5 oz) dark chocolate

While the margarine was melted in a small pot, the other ingredients were prepared in 3 separate bowls: the bananas was mashed with a fork, the flour was mixed with the baking soda, and the sugar, vanilla and eggs were whipped to a pale foamy viscous mass. The flour-mix and the melted margarine (which should be too hot) was stirred into the egg-foam and finally the mashed bananas were stirred into the batter as well.

The batter was poured into a greased and floured bread pan and baked at 175 C (350 F) for 52 minutes. After cooling in the bread pan, the cake was moved to a large plate and covered with melted dark chocolate.

After standing for several hours to let the chocolate harden, the cake was tested: it tasted just fine - so, bananas are sufficiently acidic...