Question: I don't bake very often and seem to have problems with baking powder. After it has been opened for a few months, it loses its leavening power. Do you have any suggestions on how to handle it?
Answer: Moisture and age are the two biggest enemies of baking powder. Store the powder in as dry an area as possible and be sure the lid is sealed tightly after each use. Use a clean, dry spoon when measuring so moisture will not set off any chemical reaction and lessen the product's potency.
General Foods, manufacturer of Calumet Baking Powder, says that after the can is opened, its product should remain usable for one year. The expiration date printed on the bottom of each can may be used as a guide.
You can test whether baking powder is still effective by mixing one teaspoon of the powder with one-third cup hot water. If the baking powder is still active, it will bubble vigorously.
Q: Whenever I use my baking sheets, a corner pops up and things slide to the side. What causes this? It's so distressing I have quit baking cookies.
A: Lighter-weight baking pans have a tendency to warp when they come in contact with oven heat. You might be more satisfied with a heavier baking sheet or one of the newer sheets that have an airspace sandwiched between two layers of aluminum.
When selecting baking sheets, choose the largest size that your oven will accommodate and still leave one to two inches of airspace on all sides for an even flow of heat. There should be a rim or lip on at least one short side for ease in handling. Some baking sheets have lips on both short sides to make them warp-resistant.
Sheets with shiny surfaces give a standard, light, evenly browned baked product. Darker, duller, enameled or non-stick surfaces absorb more heat and result in a darker product when baked at the same temperature and time. Baking sheets with the sandwiched airspace bake more slowly than conventional types.