Olives make for a great healthy snack and tasty ingredient in pizza, salads, and martinis. Although consuming freshly picked fruit seems ideal, both green and black olives are naturally quite bitter and therefore inedible. For this reason, olives are typically cured or pickled to extend their shelf life.
Olive Shelf Life
Freshly picked olives are processed within one or two days after being harvested to avoid deterioration. Bottled or canned olives can be stored at room temperature, unopened for one to two years. Once opened, olives can be stored in the refrigerator between three to four months.
To further extend the shelf life of olives, they can be stored in the freezer. It is important to note that liquid expands when it freezes. Olives stored in glass bottles should be transferred to a freezer-safe, sealable container to prevent bottles from exploding. This is important to remember if it is intended to keep the curing or pickling liquid. Frozen olives have an extended shelf life of up to six months.
Freezing olives is quite simple, especially for freshly picked olives that will not be processed within one or two days. The first step is to thoroughly wash the fresh olives under cool water to remove impurities. They can be left out to drain and dry in a colander. The olives can also be dried with paper towels or a kitchen towel.
Next, a suitable container with an airtight lid is best for storing olives in the freezer. It is important to leave a small gap between the olives and the lid because they expand slightly when they freeze. This is due to the high water content naturally found in olives. Date and label the containers before storing in the freezer.
Olives can be brined at home in saltwater to help retain their plump texture. For every gallon of water combine four ounces of salt and bring to boil. Add in the olives and boil for fifteen minutes. Remove the olives from the saltwater and place them in cold water to immediately to stop the cooking process. Drain in a colander and allow to dry. The olives are then ready to be stored in a freezer-safe container.
For cured olives, they do not have to be stored with their cured or pickling liquid. First, drain the cured olives and allow them to dry. Once dry, they are ready to be stored in an airtight container and frozen. The same process applies to whole, pitted, and sliced olives.
Since olives contain about 50% to 70% water, they will stick together when frozen in a container. To avoid defrosting large amounts of frozen olives, they can be stored in smaller portions. Another method that will take little effort is to flash freeze the olives.
After washing and drying the olives, line a baking tray with greaseproof paper. Arrange the olives on the tray so that they are not sticking to one another. Place in the freezer for 15 to 30 minutes until the olives are frozen. Store them in a freezer-safe container with an airtight lid or in a re-sealable bag.
Defrosting olives can be done by leaving the container at room temperature to thaw. They can also be defrosted overnight in the refrigerator to thaw out fully. The defrosted olives will have good flavor and texture for up to six months. Thawed olives will remain fresh in the refrigerator for up to three weeks.
Frozen olives contain ice crystals and eventually lose their texture and flavor even when fully thawed. Because of this, re-freezing and re-thawing olives would likely result in a mushy texture and bland flavor. To avoid the need to re-freeze olives, it is best to store them in workable portions or flash freeze them so each fruit is individually frozen and easier to use.
Effect on Olive Oil
One of the most popular olive products is olive oil. Olive storage before processing affects the aromatic profile of olive oil, mainly extra virgin olive oil. For this reason, olive oil producers have to carefully plan their fruit storage, harvesting rates, and olive oil extraction to produce the best, freshly-extracted extra virgin olive oil possible.
A study on the long-term storage of frozen olive fruits has determined that ice crystals break down their cellular structures. Because of the chemical changes, there is a major loss in flavor and texture, resulting in an attribute called “frostbitten olives.”
Technology today also allows for the artificial freezing of fresh olives for storage purposes. Freezing extends the shelf life of olive oil because it slows down microbial growth, reduces enzymatic reactions that lead to over-ripeness and spoilage, and decreases water activity.
On an industrial scale, slow freezing olives negatively affect the enzyme activity of olives and affect the resulting processed olive oil. Blast freezing and cryogenic freezing are better for fresh olives to have concentrations close to the quality of extra virgin olive oil processed from unfrozen olives.
In general, even after six months of storing fresh olives in the freezer, the extracted oils still meet commercial standards of quality. However, those who highly appreciate the certain bitterness of high-quality extra virgin olive oil may notice the lower quality of oils extracted from frozen olives.
Beyond Six Months
When stored well, fresh and cured or pickled olives can still be consumed after six months but the quality may not be as fresh as it originally was. Olives deteriorate within months even after brining because the fruits release carbon dioxide, which causes the fruit to darken and ferment.
Ensure that opened olive jars are resealed properly and that air-tight containers are used for freezing to prevent stored olives from over fermenting and spoiling before their expiry date.