A member of the onion family, garlic is both an herb and a vegetable, and its potent flavor is used to add an interesting note to countless dishes. Garlic can be found in most home kitchens, and like most natural vegetable products, it can spoil quickly if stored improperly. Garlic can be stored at room temperature for three to five months, and there are a variety of techniques that can be employed for longer-term preservation. Freezing, drying and wine immersion are the safest and most reliable methods for preserving garlic cloves in the home kitchen.
Prepare the garlic according to the desired use. Chop it finely with a kitchen knife, purée it in a food processor or blender or select whole, unpeeled cloves.
Wrap the garlic tightly with foil or plastic wrap and place it in a freezer-safe container. Be sure label the container before freezing. You can place the wrapped garlic into a plastic freezer bag with a zip-top seal if you don't have any freezer-safe containers. Unsealed garlic will absorb food odors and have a reduced shelf life.
Remove garlic as needed, taking care to ensure an airtight seal when resealing the package. Frozen garlic can be used immediately without thawing.
Peel the garlic cloves and select the ones with the fewest bruises and freshest appearance.
Slice them into 1/4-inch thick sections and place them on a cookie sheet or similar oven-safe tray.
Bake the prepared garlic slices in the oven at 140 degrees F. Cook the garlic until it is dry and crispy; this can take from 1 to 3 hours, depending on the oven. Use a blender or food processor to finely chop and process the garlic to produce garlic powder.
Select a dry white or red wine and a food-grade container.
Peel the garlic cloves, place them in the container, and pour in enough wine to submerge the cloves completely. Seal the container tightly and place it immediately into a refrigerator.
Ensure the surface of the wine is free of mold or yeast before using the stored garlic. Discard the entire container at the first signs of spoilage. Garlic preserved in this fashion should keep for approximately four months.
Combine garlic cloves with olive oil when puréeing to create a mixture that will stay soft and pliable when frozen.
Since garlic is a vegetable with relatively low acidity, it is susceptible to the growth of the bacterium Clostridium botulinum when preserved incorrectly. This produces a potent neurotoxin that can cause severe illness resulting in injury or death if ingested. Preserving garlic cloves in oil at room temperature provides an ideal breeding ground for this bacterium, and is thus not recommended. Home canning should be avoided as well, since garlic cloves require commercial equipment to be processed safely, and canning adversely affects garlic's texture and flavor.