Recipes engineered for perfection—what exactly does that mean? We take you inside Cook’s Illustrated’s science experiments.
Most recipes for sticky toffee pudding call for softening the tough, papery skins of dried dates by soaking them in baking soda–laced water. But we couldn’t help but wonder whether this actually made a difference. Were we adding an extra step where we didn’t need one?
To verify the validity of this practice, we compared dates that had been soaked in baking soda–water to dates soaked in plain water.
When we took the dried fruits out of their respective water baths, the dates soaked in baking soda–water were indeed soft and tender, while the skins of the plain water dates were leathery.
So we proved that baking soda made a difference, but why? It turns out that the skins of dried dates contain pectin, an acidic compound that acts as a glue, holding the cells of the date skin together. Soaking the dates in alkaline baking soda water sparks an acid-alkaline chemical reaction. When an acid and an alkaline come in contact, they react to form sodium salts (not to be confused with table salt). The sodium salts are soluble in water and thus get washed away from between the cells of the date skins, weakening and softening them.
MAKE IT NOW: Our recipe for Large Sticky Toffee Pudding is free through April 23rd, 2013.