Wasabi Heat: Exploring Scoville Units and Spice

How Hot Is Wasabi?

I don’t know about you, but when I eat sushi, my soy sauce turns a delicious shade of brown thanks to all the wasabi I use. The zing that bright green paste adds to a perfect piece of tuna sashimi or a delectable dragon roll just can’t be beat.

However, everyone is different and some people just can’t stand the nose clearing blast wasabi delivers.

But whether you love it or hate it, we’ve all had the experience of taking that first bite and getting the sensation of heat we know so well.

But is wasabi truly spicy or not?

The answer might surprise you.

Wasabi is not “hot” or “spicy” when compared to peppers like jalapeno, chili or habanero peppers, even though it may feel like it is. The reason for this comes down to how our we sense the “heat” in our mouths or our nose which alerts our brain that something painful is happening.

Let’s take a closer look at the difference between wasabi and chili peppers.

Wasabi and the Scoville Scale (Scoville Units)

If you don’t know what the Scoville Scale is, don’t worry, it’s very simple. It is named after Wilbur Scoville who in 1912 developed a method to test the spiciness of chili peppers.

Peppers contain capsaicin, which is the component that causes a sensation of heat when we taste it. From delectable cheeses to salsa with zip, capsaicin is naturally oily and is present in all peppers. The oiliness causes the heat from peppers to bind to receptors on our tongues.

The Scoville Scale only applies to peppers.

Wasabi is not a pepper but rather, a root, derived Wasabia japonica plant. So, if wasabi isn’t measured on the Scoville Scale, what makes it taste, or seem, hot to humans?

Name Description
Scoville Scale A measurement system for the spiciness of chili peppers, developed by Wilbur Scoville in 1912. It measures the presence of capsaicin, the component that causes the sensation of heat in peppers.
Wasabi A root derived from the Wasabia japonica plant, which is not a pepper and thus not measured on the Scoville Scale. The heat in wasabi is caused by different component.

Why Is Wasabi Different From Chili Spice?

While we sense the heat from peppers thanks to capsaicin, the sensation that we get from eating wasabi is caused by another chemical known as allyl isothiocyanate. Once introduced into our bodies, we can feel burning sensations, cough, choke or even shed tears as a reaction to it.

The difference comes down to the receptors that the capsaicin and allyl isothiocyanate both target in our bodies.

Capsaicin targets TRPV1 which is responsible for regulating body temperature and also is what causes uses to feel heat or sensations of scalding pain. In contrast, allyl isothiocyanate targets TRPA1 which is responsible for feeling pain, itching and cold in humans. When it comes to food, TRPA1 is responsible for protecting us from environmental irritants that cause us to cough, choke or tear up.

So even though wasabi doesn’t trigger our “heat sensing” gene, to us, the effect is basically the same. It’s an irritant to our system and we react in a similar way that we would when we eat an extremely spicy pepper.

In addition to the gene response, the way that capsaicin and allyl isothiocyanate enter (and remain) in our bodies is also different.  As mentioned earlier, capsaicin is naturally oily and its this oiliness that causes the chilli residue to linger on our taste buds, prolonging our agony.

In contrast, allyl isothiocyanate is a volatile chemical so once it enters your mouth, it rapidly disperses, usually through our noses. The good news is that, unlike with chili peppers, the burning sensation doesn’t last very long since the allyl isothiocyanate quickly dissipates and relief soon follows.

Name Description
Capsaicin The component that causes the sensation of heat in peppers, targets TRPV1 receptors that regulate body temperature and feeling of scalding pain.
Allyl Isothiocyanate The component that causes the sensation of heat in wasabi, targets TRPA1 receptors that responsible for feeling pain, itching and cold in humans. It quickly dissipates and relief soon follows.

Why Does Wasabi Clear the Sinuses?

Actually, wasabi doesn’t clear the sinuses no matter how much it might seem that way when we are eating it!

There has been research conducted on this topic and it was discovered that sometimes, it can lead to increased nasal congestion, or perhaps worsen it. 

The researchers discovered that the wasabi tricks the brain into perceiving that less congestion is occurring when the opposite was true.

How Hot Is Wasabi Compared to Peppers?

As discussed earlier, any comparisons to peppers is misleading since the way perception of heat in the human body is measured differs between the two.

Scoville units for various peppers measure how intense the spice of peppers is to humans. A few examples of those are:

Jalapeno peppers which have Scoville Heat Unit measurements ranging from 2,500 to 10,000.

Habanero peppers have a Scoville Heat Unit measurement that ranges from 100,000 to 300,000.

Ghost peppers have the highest Scoville Heat Units of these three, coming in at a range of between 750,000 to 1,500,000.

Since wasabi cannot be measured in the same way, it’s simple inaccurate to make comparisons such as these.

Name Scoville Heat Unit Measurement
Jalapeno peppers 2,500 to 10,000
Habanero peppers 100,000 to 300,000
Ghost peppers 750,000 to 1,500,000
Wasabi Not Measured (Not a pepper)
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