You may find that your strawberry jam will not set immediately. First-time jam makers often run into this issue, but it is easy to solve. Before you open your jar, make sure that the jam has already cooled down. Sometimes, the reason why it’s not setting immediately is that it’s still too hot. However, if your jam is still runny even after fully cooling, you can put it back in the pot and continue cooking it until it’s thick. A good test to make sure it's thick enough is to stick some on the back of a frozen spoon. If it doesn’t drip off, it’s ready