Keeping garlic fresh -- and, more important, keeping its smell from fragrancing adjacent foods unintentionally -- is simply a matter of storing it separately and with extra precaution. Garlic is packed with pungency thanks to allyl methyl sulphide, a compound present in members of the Allium family. The microscopic molecules that comprise allyl methyl sulphide drift off and attach themselves to any permeable material they can -- other foods, especially fats, and plastics aren't safe.
Whole, Chopped Raw or Cooked
Store whole heads up to three months in a dry, room-temperature cupboard. Keep cooked and chopped garlic in a double barrier consisting of airtight containers and sealable bags. No matter how great your plastic-wrap skills, you'll never wrap it airtight. An airtight storage bag and container isolates garlic's aroma -- and its allyl methyl sulphide.
In the Freezer
Raw garlic, both chopped and whole, keeps indefinitely in the freezer. Use it within 10 months for best results. Seal the garlic in a dated heavy-duty freezer bag. Squeeze as much air as possible from the freezer bag before sealing it.