Making your own horseradish takes just four ingredients: horseradish root, vinegar, salt, and courage. The goal is to get from root to jar as quickly as possible, minimizing the time you spend holding your breath, clenching your eyes, and stumbling out of the kitchen gasping for air. But if you like horseradish, you’ll enjoy the challenge. No store-bought brand can mess with your pleasure/pain center quite like the stuff you make fresh. My dad famously made horseradish from home-grown root, yet it was Mom who consumed it with the most gusto. She heaped it onto her gefilte fish, laughing through her tears about how well it cleared her sinuses. As my neuroscientist daughter points…