Wasabi Fun Facts

This is primarily pulled from Wikipedia and is super interesting.

• Wasabi, or Japanese horseradish, is a plant of the family Brassicaceae, which also includes horseradish and mustard.  A paste made from its ground rhizomes is used as a pungent condiment for sushi and other foods.  The plant grows naturally along stream beds in mountain river valleys in Japan.  The oldest record of wasabi as a food dates to the 8th century CE.  Due to issues that limit the Japanese wasabi plant’s mass cultivation, the western horseradish plant is generally used in place of the Japanese horseradish.  This version is commonly referred to as “western wasabi” in Japan.
• Wasabi favors growing conditions that restrict its wide cultivation (it is intolerant of direct sunlight, requires an air temperature between 46°F and 70°F, and prefers high humidity in summer).  This makes it impossible for growers to fully satisfy commercial demand, which makes wasabi expensive.  Therefore, outside Japan, it is rare to find real wasabi plants.  Due to its high cost, a common substitute is a mixture of horseradish, mustard, starch, and green food coloring or spinach powder.
• In some restaurants, the paste is prepared when the customer orders, and is made using a grater to grate the stem; once the paste is prepared, it loses flavor in 15 minutes if left uncovered.  In sushi preparation, chefs usually put the wasabi between the fish and the rice because covering wasabi until served preserves flavor.
• Fresh wasabi leaves can be eaten raw, having the spicy flavor of wasabi stems, but a common side effect is diarrhea.
• It is similar in taste to hot mustard or horseradish rather than chili peppers in that it stimulates the nose more than the tongue.  Because the burning sensations of wasabi are not oil based, they are short lived compared to the effects of capsaicin in chili peppers, and are washed away with food or liquid.  The sensation is felt primarily in the nasal passage.
• Inhaling or sniffing wasabi vapor has an effect like smelling salts, a property exploited by researchers attempting to create a smoke alarm for the deaf.  One deaf subject participating in a test of the prototype awoke within 10 seconds of wasabi vapor sprayed into his sleeping chamber.  The 2011 Ig Nobel Prize in Chemistry was awarded to the researchers for determining the ideal density of airborne wasabi to wake people in the event of an emergency.
• The major constituents of raw wasabi root are carbohydrates (23.5%), water (69.1%), fat (0.63%), and protein (4.8%).
• As the demand for wasabi is higher than that which is able to be produced within Japan, Japan imports copious amounts of wasabi from the U.S., Taiwan, Korea, Israel, Thailand, and New Zealand.  In North America, Wasabi is cultivated by a handful of small farmers, the most prominent of which is King Wasabi, in Forest Grove, Oregon.
• Wasabi is often grated with a metal oroshigane, but some prefer to use a more traditional tool made of dried sharkskin (fine skin on one side and coarse skin on the other).  A handmade grater with irregular shark teeth can also be used.
• Here’s a photo of horseradish: