Food Snob wrote:
> Blair P. Houghton wrote:
> > * - theoretically for capsaicin, log(16000000) = 7.204; for measured
> > values of naturally occurring peppers, log(855000) = 5.932
>
> The hottest I've ever heard of were Red Savina habaneros, which came
> in at 580,000. There's one that's 855,000 now?

Maybe, maybe not. The "Naga Jolokia" was reported to be 855,000, but
apparently it's been declared unverified:

http://www.fiery-foods.com/dave/assam_chile2.asp

The verified range now seems to be up to 300,000, and the Red Savina
only comes in at about 260,000:

http://www.fiery-foods.com/dave/heatlevels2001.html

> Have you ever used Pure Cap? Great for adding heat w/o altering
> flavor. It is right around 500,000.

Must be a brand name. Pure capsaicin is 16 million Scovilles.^ If I
want to add heat without altering flavor I'll use cayenne, but I never
want to add heat without altering flavor.

--Blair

^ - The human tongue is on average sensitive to 60 ppb capsaicin
in water*, or roughly 1 part in 16 million by weight.**

Thus, one gram of pure capsaicin is barely detectable in
16,000 liters of water (16 cubic meters; a circular
pool 4 feet deep and 13 feet across).

The "Scoville" rating of a pepper can be interpreted as the
amount of water that must be added to 1 gram of fruit paste
(including skin, flesh, membrane, and seeds) to reach the
minimum level of detectability of the sensation of "heat".
If the fruit is pure capsaicin, that number is 16 million
grams of water. If the fruit is 1 part capsaicin in 16
million parts fruit by weight, that number is 1 gram water.

So in general the Scoville rating can be scaled to give
parts per million, the concentration of capsaicin
to total weight.

For example, a jalapeno at 5000 Scovilles is 5000/16000000
or 300 ppm***. 300 ppm of 1 pound (454 grams) is 100
milligrams***. Thus the total weight of capsaicin in a pound
of jalapenos is about a tenth of a gram. Added to 9 lbs of
tomatoes this would make a sauce with 10 milligrams per
pound, or 30 ppm, or 500 Scovilles.

The American Spice Trade Association has improved the
measurement method for capsaicin to measure the chemical
concentration with a chromatograph rather than relying on
tasters, and gives values for it directly in ppm. If you
see an ASTA rating, multiply by 16 and you will know the
Scoville rating. Inversely, divide the Scoville rating by 16
to get the ppm concentration.

* - sugar water, actually.

** - however, when comparisons against control samples are
made, the tongue can tell the two apart when the one with
capsaicin is at a concentration of 1 part in 26 million or
about 40 ppb.

*** - no method of measuring concentration of capsaicin has
ever been better than 12% accurate (Scoville's method had a
50% range, reflecting the tolerances of the human tongue and
various testers' tastes), so the numbers given are never
better than 1 significant figure, and we should round our
result number to 1 significant figure as well, making it
about 300 ppm. Similarly, we will round 141 mg to 100 mg
when we calculate the weight of capsaicin as
454*5000/16000000.