You can keep cocoa powder for a long time if you store it correctly! Kept in a place that is cool, dry, and dark, it will last for up to 2 years with very little loss of flavor. Make sure that it is stored in an airtight container. You can leave it in the tin you bought it in, as long as the lid fits tightly. Although you might think that keeping cocoa powder in the fridge or freezer would help preserve it for longer, the opposite is true. Moisture has an adverse effect on its texture and can cause it to spoil more quickly.