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Olive FAQ

POSTED September 2, 2015

Detailed answers to some of the most pressing questions you might have about the extraordinary stone fruit. How are olives made ready to eat? Why do some olives have slices in their skin? Why do different kinds of olives have distinct flavors? Get your learn on.

Frequently Asked Questions about Table Olives


Are olives edible off the branch?

While olives are edible straight from the tree, they are intensely bitter.  Olives contain oleuropein and phenolic compounds, which must be removed or, at least, reduced to make the olive palatable.


How are olives cured?

There are a number of ways that an olive can be “cured,” though it is more like a fermentation process. At its simplest definition, the curing process is the conversion of the olive’s natural sugars into lactic acid and the leeching out of the bitter chemical compounds (oleuropein and phenols).  


What are the methods of olive curing?

There are many different ways that olives are cured, but in essence they all being cured in one of four different ways: natural brine, lye, salt or air curing.  


1. Natural Brine Curing

In this curing process, the olives are harvested and put into brine tanks within 24 hours.  The brine, which is simply sea salt and water, is made to an exact salinity and maintained. The process can take anywhere from three to 12 months depending on the variety. Variations of this process can include one of the following acids in curing and packing: lactic, citric, acetic or ascorbic. Certain curing combinations work to maintain flavors and textures while others work to bring out a new side.


2. Lye Processing before Natural Brine Curing

Most commonly called a “Spanish Cure” the olives are “cut” with Lye (also referred to as Caustic Soda or Sodium Hydroxide). Once harvested, olives are washed in lye solution for a period of eight to 12 hours. This process expedites the de-bittering process by leeching out the oleuropein & phenolic compounds quickly. Once this has been achieved, the olives are thoroughly washed up to three times so no traces of lye are present. The olives are then put in natural brine to ferment, allowing the olive’s sugars to convert to lactic acid. Because the olives have been quickly de-bittered the process can take, at minimum, one month and typically, no more than three.


3. Salt Curing

In areas of the Southern Mediterranean, olives are typically salt-cured. This curing process originated due to the hot, arid climate, as well as the closeness of the sea for an unlimited salt supply. Once olives are harvested, they are placed in drums where they are alternately layered between sea salt. To promote dehydration, olives are rolled in their drums weekly. After bitter compounds have been removed, olives are rinsed and coated with olive oil. The result of this cure is an olive with a similar texture to raisins and a pleasantly bitter flavor.


4. Air Curing

In some instances, olives can be fermented either on the branch or, once picked, by exposure to hot temperatures and the sun. This curing process is extremely rare and only applicable to particular varieties such as Nyon (France) and Thassos (Greece) varieties.  The resulting olive has an extremely chewy texture with a powerful but enjoyable bitterness.


What is the difference between Black Canned Olives and Table Olives?

The most significant difference between the two is that black, canned olives are not fermented. Instead, they are processed within a week, cut daily with lye to penetrate their flesh until it has reached the pit. After their lye treatments, the olives are aerated with carbon dioxide to neutralize the alkalinity caused by the lye. Next, they are exposed to ferrous gluconate for their uniform black color. The flavor of a black olive is unlike that of any table olive because of this process.


Why are table
 olives different colors?

In most situations, table olives come in a variety of colors due to their ripeness when harvested. As with other fruits, olives begin green and ripen, or mature, to a deeper shade. Depending on the variety, olives can be selected green or ripe. Each level of ripening allows for different textures and flavors. In some cases, the olive’s color is dependent on the oxidation in its fermentation process, turning it a deeper brown or black. And in the rarest of instances, olives can be colored with the addition of compounds such as ferrous gluconate or food-grade dyes.


Why do olives have distinct flavors?

Each variety of olive has distinct attributes specific to its oil content, the amount of flesh, ripeness, climate of growing, the area in which it grows and the size of the overall fruit. Also, an important factor in an olive’s flavor can be reliant on how its natural yeast, or bacteria, ferments during the curing process. For example, specific flavors, such as wine vinegar, occur naturally because of the wild yeast present (lactobacillus in this case). These yeasts are similar to what is found in grape fermentation, leading to a comparable flavor.  

Why do some olives have slices in their skin?

When an olive has been intentionally sliced it is referred to as a “cracked olive”.   This process is typically done mechanically, allowing the brine to penetrate the olive’s flesh quickly and the fruit to take on its flavors immediately. While this can be done as a usual practice, as with a particular cure of California Sevillano olives, it can also be done for necessity, as performed on some Calamata olives to achieve the proper cure.


What is the definition of natural olives?

In most all cases, olives are natural product. To further define this, DeLallo considers an olive natural when it does not contain any artificial additives, preservatives or colors. In the case of the lye processing as a means of olive production, it is solely used for processing. The lye solution used is thoroughly washed from the olives; therefore, the lye itself is not an ingredient in the fruit or the substance in which it is contained. In fact, many olives are treated with lye in their process and are certified organic by NOP standards. All DeLallo olives are natural with the exception of two: the Black Bella di Cerignola olive, which contain ferrous gluconate to give it its black color, and the Red Bella di Cerignola, which is colored with erythrosine.


Why are some olives pasteurized?

Some olives are pasteurized to control the pH level. This can also be achieved by keeping the product refrigerated, but refrigeration is the more costly of the two options. The negative effects of pasteurization are a dulled color and flesh that often becomes too soft from the extreme heat of pasteurization. DeLallo offers only one variety of pasteurized olive – the Bella di Cerignola – because it is too sensitive to keep refrigerated for extended periods. All other DeLallo olives are shipped and held refrigerated or ambient before production.

For a fun, step-by-step journey, visit our colorful adventure: Olive’s Journey to the Table!