October 26, 2013 | 1
It took me a while to come around to garlic. Now, I find it delicious, whether powdered on pizza, fire-roasted, swirled into curries and casseroles, or chopped fresh onto french fries. So, once you’ve handled garlic, how do you get that pungent odor out of your fingertips?
Mark Lorch, of Chemistry Blog and Try This at Home, proposed a “citizen scientist” experiment yesterday, based on the old wives’ tale that stainless steel surfaces could remove garlic smells.
Well, let’s try it out!
Before we get into the data, a brief foray into sulfur chemistry. Perhaps element 16 gets a bad rap, since volatile odors from rotten eggs, geysers, and flatulence all contain sulfurous compounds. Names like brimstone and vitriol (sulfuric acid) surely don’t help. But sulfur compounds pop up everywhere, from soaps and stain-resistant fabrics to the cores of metabolically important enzymes. Sulfur-sulfur bonds curl your hair, while sulfur-based drugs cure bacterial infections.
Getting back to garlic, we’re testing whether allicin (see above), a partially-oxidized disulfur compound responsible for the stinky smell, somehow interacts with metal surfaces. I’ve recruited a willing volunteer, and the following materials:
After hand-washing, I smeared each palm with a freshly-cut clove for 30 seconds. Trust me, the garlic smell could be readily detected, even at a distance!
Next, we rubbed each palm in circular motions with a stainless-steel dinner spoon and a wooden spoon, again for 30 seconds:
The result? Still stinky! We didn’t notice any major differences between the wood- and steel-rubbed palms.
Now, this is just for fun. We’re not running multiple controls, performing statistical analysis, or closely controlling variables. But my chemist brain said “OK, let’s try some more metals!” In quick order, I found some iron / carbon (hand warmers), copper (a penny) and some titanium (a ring). Like last time, we left these metals in contact with garlic oils for 30 seconds:
Results? The iron and copper surfaces stunk; we actually thought they smelled worse than the skin samples! Strangely, though, the titanium ring smelled only faintly of garlic. Interesting…and completely unexpected.
Readers, if you’d like to try this experiment, write in with what you find, either here or at Mark’s place. With more trials, we can plan some more ‘scientifically rigorous’ studies.
Update: See this 2009 NY Times article for the initial intriguing result.