Safe Mussels. If you’re using raw mussels, check that each one is still fresh by lightly tapping any that are open. If the open mussel then closes shut, it is fresh and good to eat. If it does not close within a couple of minutes, discard it. If you have mussels that were already closed they can be cooked anyway and should open, but if it does not open when cooked, do not force it open as it may be rotten. Mussels produce a strong smell when not safe to eat, so have a good sniff around before cooking!
Pre-cooked Mussels. If you can’t get any raw mussels, supermarkets sell pre-cooked packs that often come in a sauce. These sauces will often blend well with this recipe, but if you’re after a pure hoppy flavour then drain and rinse the mussels before use.