Why does garlic have a metallic smell when cooked?

[diggleblop]

Sometimes I notice a metallic smell when I have garlic bread in the oven. I think to myself, “I know I didn’t wrap that bread in foil before I put it in my toaster oven.” Sure enough, it was the garlic making that foil-esque smell when it’s being cooked. This isn’t the first time either. I basically have two questions about garlic though:

1. Why does it have a metallic smell when cooked?
2. Why is it so sticky when it’s smashed and I put it in whatever I’m making. My fingers are awful sticky after messing with garlic.

[Polycarp]

1. Allicin, the “active ingredient” in garlic so to speak, is, like chlorophyll and hemoglobin, an organometallic compound – sort of. The “netal” in uestion is the semimetal selenium. Selenium oxide has a distinct metallic odor.

2. I believe the inside of each (fresh) clove has an essential oil component. When peeling cloves of garlic for cooking, I never notice any sense of oiliness, but when handling slivered or coarse-minced garlic, I do get that slick, oily feeling on my fingers.

[Napier]

What in the world is a “metallic odor”? They almost all have such a low vapor pressure, it ought to be hard to smell them - and even mercury doesn’t seem to me to have any smell.

[jovan]

@Napier

What in the world is a “metallic odor”? They almost all have such a low vapor pressure, it ought to be hard to smell them - and even mercury doesn’t seem to me to have any smell.

In the news recently:

In the process of conducting research on iron plumbing infrastructure and drinking water quality, two Virginia Tech researchers in the College of Engineering uncovered that the smell of iron when you touch metal is really not iron at all.

(…)

In their paper, Dietrich and Glindemann explain the source of the “metallic” odor that is generated when a person picks up keys, coins or metal objects. The odor results from a metal induced oxidation of skin lipids so it is surprisingly a type of human body odor. The compounds people smell are actually aldehydes and ketones, and not any iron containing compounds.

(…)

One of the products produced when skin comes in contact with metal is octeneone (OEO). Humans can smell OEO at concentrations as low as 5 parts per trillion, which indicates humans are highly evolved for detecting this compound. “The fact that iron metal produces a whole host of “smelly” organic molecules when humans touch it or acid attacks it was unexpected.