You might think you know about black and green olives, but if I asked you right now whether they're a fruit, vegetable, or neither, would you hesitate before answering? Don't worry - you're not the only one!
Until recently I didn't know this much about olives either. After all, I know that I like Greek but not Italian ones and green but not black ones, but I didn't know how to classify them or why I had those opinions.
What Are Olives and How Are They Grown?
Olives are a small, oval fruit with hard stones (or pits) in the middle. They're traditionally grown across the Mediterranean but can also grow in climates like that of California.
Fun fact: because olives have one singular stone, they are considered to be a 'drupe'. This puts them in the same category as other fruits like peaches and cherries. However, olives have a much lower sugar content and a sky-high oil content in comparison!
They grow on evergreen trees which grow incredibly slowly, and once the tree is of a decent size, it's pretty good at withstanding drought. They're best grown outdoors in sunny areas.
Despite the fact that the trees can get pretty big, they can still grow in pots as they grow so slowly. They have relatively small pale green-grey leaves and in most places, won't produce fruit (and not edible fruit unless you're lucky enough to live in one of the below places and know how to care for them well).
However, this is not a gardening blog, so I think you can find out more from other sites if you'd really like to grow your own olives.
They're also historically important, especially in the Mediterranean. However, they're not actually native to the Mediterranean - they're actually native to Syria and other parts of Asia
Region and Climate
Olives aren't just grown in the Mediterranean - they can also be grown in other places with similar climates such as:
- South Africa
- New Zealand
So really, places with mild winters and long, warm, dry summers. It's really classed as a subtropical climate more than anything!
So, if you live in one of those countries and fancy growing olives then why not give it a go?
Black Olives vs. Green Olives
Olives come in various shades of green and black depending on when they're picked. Green olives are typically firmer as they're unripe, while black olives are fully ripe and are softer.
Green olives are picked at the start of the harvest season in September and October. Black olives are picked in November and December, or sometimes as late as January.
To some extent, the curing process can also affect the colors of olives as they are inedible when raw and freshly picked. They're very strong and bitter, so both colors are cured either by being packed in salt, brine or water, before being eaten.
Sometimes, olives are lye-cured, which involves raw olives being soaked in an alkaline lye solution. However, this can affect their flavor so is typically used by large, commercial olive producers.
However, there's no way to avoid it as it won't be shown on food labels, so determining whether it was used is very difficult.
Generally, green olives are denser, firmer, and more bitter than black olives. However, the curing process does also affect the flavor and texture so it's difficult to compare them.
Regional Olive Oils
The differences between regional olive oils are due to a lot of factors. For example, both Greece and Italy are known for their olive oil, but their oils are both unique because:
- the type of soil the trees were grown in (which also varies within the countries from North to South etc.)
- the type of olive tree the olives grew on
- the individual climate in the small area where the trees were grown
- the production method whether mass-produced or on a smaller scale
- the regulation of olive oil in each country
- the price (a very great factor - if you buy cheap oil, it won't be the same quality!)
Even the color of Greek olive oil is different to that of Italian olive oil.
Different Olive Varieties
When it comes to the varieties of olive, their names do often give away where they're from (or where the tree species is from):
- Castelvetrano - sweet and mild bright green Italian olives that go very well with sheep's milk cheese and crisp white wine
- Kalamata - deep purple Greek olives with an almond shape - perfect for tapenades
- Cerignola - very large green olives harvested in the Puglia region of Italy. They're crisp, buttery and great for stuffing or serving with garlic, cheese, capers and anchovies
- Nyon - smaller jet-black, bitter olives from South France. They're wrinkly and are best served dressed with Provencal olive oil and fragrant herbs like rosemary and thyme
- Nicoise - a very important ingredient in classic dishes from the French Riviera such as salade Nicoise and tapenade. They have a faint liquorice flavour
- Liguria - these are also called Taggiasca olives and are rather small, but with big flavours. They're grown in Liguria in North-West Italy - close to the French Nicoise region
- Gaeta - small purple-brown, wrinkled olives from Puglia, Italy with soft fresh and a citrusy tart taste
- Picholine - torpedo-shaped French green olives that are crisp and crunchy with a nutty, tart and anise-y flavour
- Gordal - these are fat Spanish olives that are firm and meaty. They're grown in Andalucia and are often used in tapas
- Alfonso - large, deep purple olives grown in Peru, despite the variety traditionally being considered Chilean
- Mission - American olives that were originally believed to be of Spanish origin, but could not be linked to any of Spain's 700 olive varieties. They're grown in California and most are used to make olive oil
- Manzanilla - oval-shaped Spanish olives with a slightly smoky almond flavour that are often stuffed with pimientos
- Beldi - one of the few types of Moroccan olives that are exported. They're intensely flavourful and are best in salads, tagines or sprinkled with olive oil and hot peppers
- Amfissa - prized Greek olives grown in Delphi that are mild, fruity and almost melt-in-the-mouth soft
Does it Matter How the Olives Are Cured?
Quick answer: yes!
The cure is what gives the olives their saltiness, texture and flavor.
Olive curing is actually more like fermentation if anything - it's a conversion of natural sugars into lactic acid.
Here are the types of brining method:
- brine-curing - fully-ripened dark purple or black olives are fermented in brine (saltwater) which can take up to a year. These olives will become sweet with a great depth of flavour as the brine intensifies the fruit's natural flavours.
- water-curing - soaking, rinsing in plain water and then repeating... for a very long time! This method is the slowest and so is now quite rare. Some producers start their curing process in a water process and then move the olives into a seasoned brine instead.
- dry-curing - the olives get packed in salt for a month or longer. The salt pulls moisture and bitterness out of the olives, so when the salt is removed, the olives are often wrinkled due to the loss of moisture. This means that then they'll sometimes be bathed in olive oil to keep them juicy and plump.
- oil-curing - these olives are dry-cured and then macerated or softened in oil for several months.
- lye-curing - the most cost-effective method, which was invented in Spain. The raw olives are immersed in vats of alkaline lye solution, which is also detrimental to the olive's flavour as it leaves behind a chemical aftertaste.
- sun/air-curing - in rare cases, olives are fermented either on the branch or once picked by basking in the sunshine.
Pitted vs Whole Olives
For just eating as they are, I'd recommend using whole olives as once pitted they can become a little softer - plus, when they're pitted, some of the flesh is also lost which means that there's less olive per olive if they're pitted.
This is also the case for if you're creating your own marinade.
However, for cooking with, I'd recommend using pitted as it's easier - nobody wants to have to spit out a pit every other bite of a meal!