Scoville Scale, table and Heat levels

Capsaicin is an 8-methyl N-vanillyl 6-nonenamide, in whose name the relationship to vanilla can already be discovered. This is not by chance because both have their origin quite certainly on the Yucatán Peninsula in the Gulf of Mexico.

A different ratio of capsaicin and dihydrocapsaicin accounts for a different perception of spiciness in humans. In addition to these two main capsaicinoids, there are others, such as nordihydrocapsaicin, homocapsaicin, and homodihydrocapsaicin, which can also contribute to the pungency of chillies, but to a lesser sharpness.

Often the ratio of capsaicin and dihydrocapsaicin is balanced. However, we perceive the heat level of habaneros and rocotos differently for the same total amount of both capsaicinoids. Rocoto pods tend to have lower levels of capsaicin than habaneros. Thus, habanero can burn like hell, while a rocoto seems mild.

The unit of measurement for the scale is SHU, which stands for “Scoville Heat Units.” Sporadically, you can find the abbreviation SCU, which is the same thing, only without “Heat”.

Today, the amount of capsaicin is determined with an HPLC (High Pressure Liquid Chromatography) measuring instrument. In German, this instrument has the long name “High Pressure Liquid Chromatography”. In these instruments, the liquid is broken down into its individual molecules and their quantity is determined. The result is displayed as a curve on a monitor. Here you can read which molecule is present in the corresponding concentration. Those who want to buy such a Scoville measuring device for the degree of sharpness should plan on 10.000 Dollar and more.

But it’s also easier. Even today, the method of the inventor of the Scoville scale can be applied by anyone. Wilbur Scoville worked for the Parke Davis Pharmaceutical Company in 1912. In order to make his studies on capsaicin comparable, he needed a resilient measurement method. And this is as simple as it is easy to understand.

In an American journal for pharmacists, he described his actual measurement method in just four sentences:

This is the method I used. One gram of ground chilli is soaked overnight in 100 ml alcohol.
Then it is shaken and filtered. Drinking water is added to the (hot) alcohol until no pain is felt on the tongue.
– Wilbur Scoville

Wilbur Scoville stated in his publication that he measured one Japan Chilies each with 20,000 and 30,000. Zanzibar Chilies with 40.000 and 45.000 and Mombasa Chillies with 50.000 and 100.000.

If one chili is twice as hot as another, twice the amount of water is needed to neutralize the heat. This means in reverse, the Scoville Scala is linear.

Less accurate is the degree of sharpness. This is a subjective perception of how sharp the chili is perceived by yourself.

Sweet peppers without pungency has a 0 Scotch Bonnet a 10. The extremely pungent varieties, like the currently the hottest chili in the world, Carolina Reaper get up to three plus behind the ten. So for the Trinidad Scorpion Butch T, Moruga and Carolina Reaper there is a 10+++.

The hotness of chillies can vary depending on cultivation, harvest, and processing. This may mean that the hotness of a chilli variety in practice differs from the values given in the table.