When growing mushrooms, inoculating a substrate with spores or mycelium can be quite an exciting moment. After spending hours cleaning, pressure cooking and sterilizing equipment, it is frustrating to find contamination in its substrate. All precautions taken, these contaminations are often due to air that you cannot sterilize. Fungal spores and bacteria will then colonize the substrate instead of your culture, thus ruining your efforts. But don't panic, there is a solution! You can get around this problem by using a laminar flow hood. The latter creates an environment with sterile air. The laminar flow hood is equipped with a HEPA filter which cleans the air of any contaminants and then expels sterile air to your work space.