Can you smell that? Mmmmm, garlic.

A few nights back, I went to an Indian restaurant with my family. I do enjoy Indian food, but my favourite would have to be garlic naan! I also love garlic bread and garlic pizzas (are you sensing a theme here?).


Mmmmmm… But maybe not raw.

The garlic naan on this particular night, however, was a little bit tooooo garlicky. Some family members complained that it was spicy, as though pepper or chilli had accidentally been placed on top. However, this was just the effect of too much garlic! The chemical component of garlic which is responsible for this burning, spicy taste, is allicin.

Interestingly, allicin is not present naturally in garlic. When garlic is crushed or cut, enzymes then convert the compound alliin to allicin, which provides that well-known aroma. The use of heat with garlic will also cause this conversion, which explains why we smell that strong smell when cooking up garlic and onion for a Bolognese sauce, and not so much when the clove is sitting whole in our kitchen.


Allicin is only found once garlic is chopped or cut!

As for the other effect of garlic, bad breath, that is actually due mainly to four different chemical compounds, which are once again only observable in garlic once we cut, crush or chop it: diallyl disulfide, allyl methyl sulfide, allyl mercaptan and allyl methyl disulfide. You can find the structures on this great infographic from Compound Interest.


Of course, one of my favourite sites ever has an infographic on one of my favourite spices ever!

One thing you will notice in these structures is that they each contain an ‘S’. This ‘S’ stands for sulphur (or sulfur depending on where you come from!). Other things that you may think about when you hear are rotten eggs (the smell of which is made of hydrogen sulphide, H2S) and fire/ volcanoes (‘brimstone’ is the ancient name for sulphur). Methanethiol, another sulphur compound, is believed to be one of those responsible for smelly urine after eating asparagus. But it’s not all bad news. Saccharin (an artificial sweetener), proteins, and penicillin all contain sulfur, and they’re not smelly… well at least not while they’re fresh.

It is thought that our dislike of sulfur-containing volatile compounds is due to our need to avoid unfresh foods. Some sulfur-containing compounds are produced when proteins in putrid food break down. Then the human body is able to detect these compounds, even at quite low concentrations, so that we know to avoid that particular food.

But (potentially) good news everyone. There are a couple of foods known to eliminate that lovely smell for when you want to kiss your loved ones or tone down the ‘spice’ of a meal. In cooking, you can use tricks such as roasting the garlic or leaving it to sit for ten minutes after crushing, or by adding potato or parsley to your meal. Parsley or milk, as well as as-much-gum-and-mouthwash-and-mints-as-you-can-handle are among your options for bad breath.


Chow down on a sprig of parsley, it’s supposed to help!

As a side note, some of the researched effects of garlic include antibiotic, anticancer, blood thinning, antiviral, and antifungal effects. So, to stink or not to stink?

Please see this website from the Linus Pauling Institute if you would like some more detailed information on Garlic and it’s health effects.