Garlic is probably the most widely used spice in the world having been used for thousands of years. It is available in many forms, including fresh heads, dried flakes and powder, salt, extract and even juice. However fresh should always be the first choice.

The characteristic odour is formed when enzymes and other compounds come into contact with each other. This is normally caused by crushing, slicing, or chopping. In other words, the more finely it is chopped, the more pungent it becomes. This accounts for why some recipes would have you mash the garlic to a pulp (as in aioli and pesto Genovese) for the maximum flavour, and others require a more restrained chopping, slicing, and even leaving the cloves whole in order to moderate the flavour.