Scoville scale facts for kids
The Scoville scale is a handy scientific tool. It provides a measurement of spiciness in different chili peppers. People record these levels using numbers called Scoville heat units (SHU). The heat comes from special natural chemicals called capsaicinoids. The most famous of these chemicals is capsaicin.
An American scientist named Wilbur Scoville invented the test in 1912. His first method was known as the Scoville taste test. It relied on a subjective assessment from human volunteers who tasted peppers. Today, labs use a modern machine method called high-performance liquid chromatography (HPLC). This test measures the exact chemical pungency without burning any tongues!
Contents
How the Original Taste Test Worked
Wilbur Scoville designed his test to see how spicy a pepper was. First, scientists dried a pepper sample and mixed it with alcohol. This step extracted the hot capsaicin chemicals into a liquid. Next, they blended drops of this spicy liquid into sweetened sugar water.
A panel of five trained human taste testers sampled the mixture. Testers sipped solutions that became less spicy over time. The team added sugar water until three testers could not feel heat. This dilution level gave the pepper its official score in Scoville heat units.
However, the taste test had several big weaknesses. Every human tongue has a different number of heat receptors. Some people can handle spicy food much better than other people. Testers also experienced sensory fatigue after tasting just a few samples. Their mouths quickly became numb to the heat! Because of these issues, scores between different labs varied greatly.
Modern Testing with High-Tech Machines
In the 1980s, scientists switched to a much more accurate machine method. This technique is called high-performance liquid chromatography, or HPLC for short. HPLC separates the capsaicin chemicals from the rest of the pepper. It measures the exact concentration of heat-producing molecules.
The American Spice Trade Association defined these results as pungency units. Scientists measure the chemical amount as parts per million of heat (ppmH). They measure dried pepper mass mixed into a chemical called acetonitrile. The test also measures another spicy compound named dihydrocapsaicin.
Computers turn these chemical numbers back into classic Scoville heat units. Scientists multiply the parts-per-million value by a factor of 16. This provides a fast, reliable score without human guessing.
Heat Ratings of Common Chili Peppers
Capsicum chili pepper plants are very popular in cooking all around the world. Their heat scores range from zero all the way to millions of units. Not every pepper of the same type has the exact same heat. A pepper's heat depends on its seed lineage and growing conditions. Weather, humidity, soil quality, and ripening change how much capsaicin develops. Even fresh peppers with lots of water taste different from dried powders. Some wild peppers like the Guntur chilli and the Rocoto have very wide ranges. Others like the Dragon's Breath pepper are still being tested by plant scientists.
| Scoville heat units | Examples |
|---|---|
| 2,693,000 | Pepper X |
| 1,500,000–2,500,000 | Carolina Reaper |
| 750,000–1,500,000 | Trinidad Moruga scorpion, Naga Viper pepper, Infinity chili, Ghost pepper |
| 350,000–750,000 | Red savina habanero |
| 100,000–350,000 | Habanero chili, Scotch bonnet pepper, Madame Jeanette |
| 50,000–100,000 | Bird's eye chili, Malagueta pepper |
| 25,000–50,000 | Tabasco pepper, Cayenne pepper |
| 10,000–25,000 | Serrano pepper, Aleppo pepper, Cheongyang chili pepper |
| 2,500–10,000 | Jalapeño pepper, Guajillo chili |
| 1,000–2,500 | Poblano pepper |
| 500–1,000 | Cubanelle, Beaver Dam pepper |
| 0–500 | Banana pepper, Friggitello, Pimiento |
| 0 | Bell pepper, Peperone crusco |
Pure Chemicals and Other Spicy Compounds
Scientists can also measure individual spicy chemicals in the laboratory. There is a direct linear correlation between capsaicinoid concentration and heat ratings. Pure capsaicin rates at 16 million Scoville heat units all by itself! Related plant chemicals include nonivamide, nordihydrocapsaicin, homocapsaicin, and homodihydrocapsaicin.
These chemicals trigger a sensor in our body called the TRPV1 receptor. Other plants produce different chemicals that can also feel hot to humans. For instance, ginger contains gingerol, black pepper contains piperine, and cooked ginger has shogaol. Some wild plants in the Euphorbia family make chemicals like resiniferatoxin and tinyatoxin. Resiniferatoxin is so intensely hot that it scores 16 billion heat units! Scientists study these unusual chemicals to learn how human nerves sense heat.
See also
In Spanish: Escala Scoville para niños
- List of capsaicinoids
- Pyruvate scale
