Why Doesn’t Garlic Smell Until You Cut It? The Agronomist Explains

Garlic, the blessing and curse of cardiologists and gourmets, is an ingredient with a thousand facets. Loved for its beneficial properties, it is feared for its persistent breath and the odor it gives off from its skin. But why does whole garlic have no odor? We automatically associate garlic with its scent, hated or loved by people, but in reality, if you think about it, the heads of garlic you buy at the greengrocer's or supermarket have no odor whatsoever. Why then does it have such an intense odor when we eat it?

Whole garlic doesn't have a strong odor because the chemicals responsible for its distinctive aroma are "dormant" inside the cells. When you chop, crush, or chew garlic, you break down the cell structure and release an enzyme called alliinase, which comes into contact with an odorless compound called alliin. This chemical reaction turns alliin into allicin, the molecule that gives garlic its pungent odor. Allicin is highly volatile, meaning it quickly diffuses through the air, reaching your nose almost instantly. The finer the garlic is chopped or crushed, the more of the enzyme is released and the stronger the odor. If you cook it, however, the allicin breaks down into other, milder sulfur compounds, giving garlic a milder, sweeter aroma.

Whole Garlic Has No Odor, But Chopped Garlic "Stinks": Let's See What Science Says

Agronomist Daniele Paci recently explained the phenomenon on his Instagram profile: "Garlic has no smell until you destroy its cells. The smell of garlic is due to a substance called allicin that is not in garlic. In garlic there is a precursor that becomes allicin when it meets an enzyme that transforms it. However, this never happens unless you destroy the cells by cutting the garlic". This step is essential because the precursor and the enzyme are found in two different "places" inside the clove, so only by destroying the cells can we make them meet. And how do we destroy the cells? By chopping the garlic. "When we have a whole garlic clove, in good condition, we don't smell anything. If we want a little smell, we have to crush it. If we want a lot of smell, we have to destroy a lot of cells. We get the most when we grate the garlic" says Paci.

Is there a way to avoid this pungent smell? According to the science communicator, if you don't want the garlic smell, just cook it for a short time at 150-160°F/65-70°C. In this way "the enzyme is destroyed and we no longer have the possibility of creating this smell".

This chemical mechanism is a form of defense of the plant. Allicin has antimicrobial properties and can protect garlic from parasites and predators. It is the same mechanism that is activated with onions, for this reason we start to cry only when we cut them and the more we chop them, the more we risk flooding the house with our tears.