I used this method before i acquired a flow hood, it works well if you are doing innoculations or making casings. This method is not recommended for Agar or grain to grain transfers. It is important to work quickly as the tray/rack cools fast.
Of course, this is only one aspect of sterile technique; you will want to practice other aspects as well.
Of course, this is only one aspect of sterile technique; you will want to practice other aspects as well.