In Scoville's method, an alcohol extract of the capsaicin oil from a measured amount of dried pepper is added incrementally to a solution of sugar in water until the "heat" is just detectable by a panel of (usually five) tasters; the degree of dilution gives its measure on the Scoville scale. Thus a sweet pepper or a bell pepper, containing no capsaicin at all, has a Scoville rating of zero, meaning no heat detectable. The hottest chilis, such as habaneros and nagas, have a rating of 200,000 or more, indicating that their extract must be diluted over 200,000 times before the capsaicin presence is undetectable. The greatest weakness of the Scoville Organoleptic Test is its imprecision, because it relies on human subjectivity. Tasters taste only one sample per session.
First, this is not a "bash the good pharmacist Scoville" topic - I <3 the dude and love the scale. It's also led to several hilarious interpretations (the best by Cracked I think http://www.cracked.com/article_19187_the-science-behind-stupidly-hot-peppers-5Bchart5D.html) ....but since it's subjective and relies on something as variable as human taste buds and tolerance for peppers/capsaicin, I always wonder about Scoville units when they get into those ridiculously high stratospheres.
While browsing pepper stuff, I stumbled onto this on the Livestrong site of all places: http://www.livestrong.com/article/447263-peppers-with-most-capsaicin/
I see things like "1,001,304" - how do they determine it down to the single digit unit?!? Seriously - 1,001,304? And how do they tell the difference between 1,001,304 and 1,001,507?
The other part that concerns me about the scale is that while it sounds pretty scientific and they call out one flaw, they seem to potentially ignore another.
Tasters taste only one sample per session
My good friend from Thailand used to take me to all his favorite Thai food restaurants. And man - I know the Thai chili isn't up there with the big boys, but he'd order in Thai, and order "Thai Spicy" . I'd order 3, sometimes 4 stars but i'd try his and those dishes made my eyeballs sweat. Just ridiculous heat. And he'd order a side of Thai chilis, minced - he'd grab a couple big handfuls and sprinkle it alllll over his food.
I asked him how he could do that and he said after a lifetime of eating food that hot he didn't taste it any more. He needed that much to get heat. We in the western world are reared on PB&J and milk, not 5 star massaman curry and peanut sauce.
So more than the interval for the tester between tastings, wouldn't you also have to check their background or lineage? It seems eating copious amounts of capsaicin as a child - in your mother's milk, and her mother's before her may have a cumulative effect? Granted, my method is way less scientific since I'm basing it off one guy at a restaurant, but you can't tell me Thai people don't eat up loads of bigtime fire on a regular basis. I know when you see uploaded videos of people tasting the "new hottest pepper" and rolling on the floor vomiting unholy fire from their shoes it's always, always goofy white dudes. I've never seen one of those with a Thai in it. heh
Anyone have thoughts on this? Is there really no way to chemically test the strength of a hot pepper? Would love any information (or wild speculation, or humor) anyone has on this.