Wilbur Scoville and a hidden passion for chilis at Google

A Google Doodle celebrates the pharmacist who developed an objective scale for spiciness and proves that while some things can't be measured, chili peppers can be scored easily.

Wilbur Scoville, who was born 151 years ago Friday, developed the Scoville organoleptic test, the first test to assign spicy foods a number based on the heat-inducing sensation they produce, the Telegraph reported. A New England native, Mr. Scoville's pharmaceutical work was lauded in his lifetime, and the Scoville scale he created is still used today.

The Scoville scale ranges from zero – a green bell pepper – to 16 million Scoville Heat Units, according to the Telegraph. Scoville originally based it on how many cups of water would be needed to dilute a given pepper to zero tasteable spiciness.

The Google Doodle invites visitors to play a game based on Scoville's theorized "research methods." Scoville eats a pepper, and the visitor must guess how much ice cream he needs to counter its heat. The peppers become progressively spicier, and each user is assigned a spiciness rating based on scale.

Anyone who has ever encountered a hot curry or plate of enchiladas knows there is nothing imagined about the potentially debilitating power of spicy food, nor dispute that the "mild" salsa verde mild produced a lesser mouth-burning sensation than a "hot" salsa beside it. At the same time, most would not immediately agree that the salsa or the curry deserved a number on an objective scale, especially if they began reaching for the water pitcher while their neighbor went back for third helpings.

To counter this, modern scientists have refined Scoville's scale somewhat and now use high performance liquid chromatography, Twilight Greenaway reported for Smithsonian Magazine.

“It’s easy to get what’s called taster’s fatigue,” Dr. Paul Bosland, professor of horticulture at New Mexico State University, told Smithsonian Magazine. “Pretty soon your receptors are worn out or overused, and you can’t taste anymore."

This system counters "taster's fatigue" by analyzing the concentration of capsaicin – the pepper's heat-inducing compound – in a given chili pepper, Smithsonian Magazine reported. The parts capsaicin per million, multiplied by 16, is roughly equal to the Scoville rating that tasters could provide, or at least "close enough," Bosland said.

Scoville's rating system may not account for variation among pepper-tasters, but the variation of heat level among peppers has an objective explanation. Peppers that grow in a "stressful" environment, suffering from heat waves, low water, or poor soil during the cultivation period, produce more defensive capsaicin, which means they taste spicier, Danise Coon of the Chile Pepper Institute at New Mexico State University said in a website release.

For example, a jalapeño grown in New Mexico is generally hotter than an otherwise similar jalapeño grown in California. Tasting that variation, however, can require a palate refined by experience.