Welcome to brain Stuff, a production of I Heart Radio, Hey brain Stuff, Lauren Boga bam here. If the wassabi that the waiter brings out to a company your sushi could talk, it would have some explaining to do. It's highly unlikely that that pungent green paste is the real thing. It's probably not even close. The wissabi served in American restaurants is actually a mixture of mustard, horseradish, and green
food coloring. That's because real sabi is very expensive, sometimes more than a hundred dollars a pound outside of Japan. Though even in Japan it's rare for restaurants to use it because it's not cheap and it must be freshly graded. The part of the wisabi plant that's used as a condiment is the rhizome. It's a root like stem that grows underground, like ginger or potatoes. The whole plant is actually edible, but the rhizome is especially prized for its
sharp flavors. If you're lucky enough to go to a restaurant serving the real thing, they may even bring the rhizome to the table along with greater so that they can grade it as freshly as possible for you. That's because wassabi starts to lose its kick around fifteen minutes after being graded or cut. Because that amazing kick comes from one of the plant's defense mechanisms, and it's not a permanent feature of the rhizome. You see, Wasabi doesn't
have much scent until it's cut or grated. But when its cell walls are broken, say by the teeth of a hungry herbivore or a chef's knife, compounds from inside and outside those cells mix and undergo a chemical chain reaction that creates pot tasting compounds during one phase of the chain. This is an evolutionary trait meant to deter animals from eating the plant, But suckers, we humans have
decided that we dig that flavor. While imitation with sabi is very hot with a mustard pepper sort of flavor, the real stuff doesn't have the same harshness or burn and tastes more vegetile, earthy, and smooth with just a hint of sweetness. Was Sabi is so expensive because it's hard to cul to eight. It's known as the hardest plant to grow commercially in the world. The best was zabi called Sabo sabi is grown in flooded beds of
gravel or preferably in cool mountain streams. The roots sink down into the soil below, the rhizomes grow in the gravel, and the leaf stems poke up above the water. Lower quality plants are grown in fields in soil called oka wasabi for processing into dried powder for snack crackers and the like. But either way, was sabi's leaves and stems are brittle. It wants temperatures to stay between fifty and seventy degrees fahrenheit that's about eight to twenty celsius, and
like me, it won't tolerate direct sunlight. It doesn't do well in greenhouses, so it can really only be grown in appropriate natural environments. So when restaurants are trying to keep costs down, they substitute the aforementioned horse radish mixture for real was sabi. The reason this works is because both ingredients get their pungency from the same family of herbivore deterrent compounds called isothiot Science nates and scientists are
looking into a sabi's medicinal properties. It appears to relieve allergy symptoms, fight cancer, and inhibit bacterial growth, though more research is needed. The antimicrobial attribute might be why it traditionally accompanies sushi. It's a way of counteracting any possible ill effects of eating raw fish. Today's episode was written by Katherine Whitburn and produced by Tyler Clang. The brain Stuff is production of I Heart Radios How Stuff Works.
To learn more about the history, science, and culture of sabi, check out my other podcast, Saber. We did an episode on it in December, and of course, for more on this and lots of other hot topics, visit our home planet has Stuff works dot com plus for more podcasts from my Heart Radio with the I Heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.