Nanotubes and hot sauces

Hot sauce aficionados may be familiar with the Scoville Scale, used to express the heat of a sauce or pepper. The other day, my friend Antonia sent me an article explaining that the process of determining a Scoville rating might be significantly refined, thanks to carbon nanotubes:

The well-established Scoville method – currently the industry standard – involves diluting a sample until five trained taste testers cannot detect any heat from the chilli. The number of dilutions is called the Scoville rating; the relatively mild Jalapeño ranges from around 2,500-8,000, whereas the hottest chilli in the world, the ‘Naga Jolokia’, has a rating of 1,000,000. High performance liquid chromatography (HPLC) can also be used but this requires bulky, expensive equipment and detailed analysis of the capsaicinoids.

In Compton’s method, the capsaicinoids are adsorbed onto multi-walled carbon nanotube (MWCNT) electrodes. The team measures the current change as the capsaicinoids are oxidised by an electrochemical reaction, and this reading can be translated into Scoville units. The technique is called adsorptive stripping voltammetry (ASV), and is a relatively simple electrochemical method.

The Scoville Scale is pretty easy to understand. A sauce with a rating of 1000 can be diluted 1:1 with water to produce a sauce with a rating of 500. Tabasco sauce, of the sort ubiquitous in diners, has a rating of between 2,500 and 5,000. Dave’s Insanity Sauce – the spiciest one in my kitchen – has a rating of about 180,000. Even taking the upper estimate of Tabasco’s potency, that means one tablespoon of Dave’s is equivalent to about half a litre of Tabasco.

Of course, those who truly wish for their epithelial cells to signal as much heat and abrasion as is theoretically possible can do better. Blair’s 16 Million Reserve, which consists of a little bottle of pure capsaicin crystals, weighs in at 16,000,000 Scoville heat units. One tablespoon is thus akin to 1.31 litres of Dave’s Insanity Sauce, or 47.16 litres of Tabasco. Just the thing you need if you want to turn a bland chili dinner for your million person standing army into something a bit more interesting.

Author: Milan

In the spring of 2005, I graduated from the University of British Columbia with a degree in International Relations and a general focus in the area of environmental politics. In the fall of 2005, I began reading for an M.Phil in IR at Wadham College, Oxford. Outside school, I am very interested in photography, writing, and the outdoors. I am writing this blog to keep in touch with friends and family around the world, provide a more personal view of graduate student life in Oxford, and pass on some lessons I've learned here. View all posts by Milan