“Baking soda isn't unsafe to eat after the best-by date,” says Vu ... Read More: Baking Soda vs. Baking Powder: A Pastry Chef Explains the Difference To test baking soda for freshness ...

Self-raising flour is widely available in UK supermarkets. Outside of the UK and USA, it is not commonly used. Self-raising flour will not keep for very long. The baking powder absorbs moisture ...