This question is somewhat similar to these two ones – does chocolate powder expire and how long does chocolate powder last? However, they have different emphases. Typically, you would ask this question only when you’ve found something wrong with the cocoa powder or it still looks good even after the printed date. That’s to say, this question focuses on safety while the latter two on quality. Obviously, it is important to tell them apart before answering it.
Usually, the “best-by” date labeled on package and storage methods determine the shelf life of any foods. Cocoa is no exception. In general, providing that a good storage is ensured it lasts for 2 years when unopened while it last for 1 year when opened. Even so, there’s more to say about this topic since, as briefly mentioned above, safety and quality is two different concepts.
Firstly, it is recommended to be used before the best before date. Just to be clear, it doesn’t necessarily mean that it will go bad after it expires. Usually this deadline focuses on the quality and flavor more than the safety. In other words, the aroma and texture of cocoa powder will gradually disappear over time since it is still somewhat exposed to air, opened or unopened. This is because no manufacturer is able to keep it in a 100% airtight container. So, when it is properly stored, it is still safe although its taste and flavor have somewhat changed.
Secondarily, when it starts to spoil or go rotten. You’d better discard it right away since the consumption of spoiled cocoa may make you ill or, worse still, involve other severe health risks. Generally, you can tell spoiled cocoa by the look and the smell. If these methods fail, your taste buds will give you a more reliable answer if it still looks good and smells good.
Thirdly, if it has been added with powdered milk or other dairy products, for example instant white hot chocolate mix, it tends to be easier to go bad. That’s to say, it often has a shorter shelf life.
Finally, in order to make cocoa powder last as long as possible, you really should put it in a dry, cool place. And you’d better use it prior to the expiration. In addition, throw it away once it has lost the chocolate taste.