19 December: Olives

Ten facts about Olives for French Revolutionary Calendar's Day of the Olive.

1. The botanical name is Olea europaea, meaning "european olive".
2. Why are some olives green and others Black? It's to do with how ripe they are when they are harvested. The black ones are fully ripe; the green ones are picked before ripening has begun. Green olives are picked from the middle of October to the end of November, and black olives are collected from the middle of November to the end of January or early February.
3. Freshly picked olives are very bitter because they contain oleuropein, a bitter phenolic compound at levels of up to 14%. The curing process takes from a few days, with lye, to a few months with brine or Salt.
4. Olives have been an important crop for millennia. As far back as 3000 BC, olives were grown commercially in Crete; they may have been the source of the wealth of the Minoan civilization. In fact, the English word "oil" derives from the word for olive tree in several ancient languages.
5. Olive oil is widely used today. Spain in the biggest producer (39% of world production in 2013) while Greece is the biggest consumer (over 24 litres per person per year). "Virgin" means that the oil was produced by the use of mechanical means only, with no chemical treatment.
6. In 2011 there were about 9.6 million hectares planted with olive trees throughout the world, making olives one of the most extensively cultivated fruit crops in the world. Only coconut trees and oil palms take up more space.
7. The original Olympic "eternal flame" was fuelled by olive oil. It was used to to anoint kings and athletes in ancient Greece and was burned in temple lamps. In the Jewish religion, olive oil is the only fuel allowed to be used in the seven-branched Menorah in the Mishkan service during the Exodus of the tribes of Israel from Egypt, and later in the permanent Temple in Jerusalem. It was obtained by using only the first drop from a squeezed olive and was consecrated for use only in the Temple by the priests and stored in special containers.
8. Both the Bible and the Quran mention olives as an important and prized fruit. An olive branch, particularly when depicted in a dove's beak, is a symbol of peace. Olive branches appear on the flag and coat of arms of Cyprus, the flag of Eritrea, and the Great Seal of the United States. Crowns of olive leaves were presented to the victors of battles and games in ancient Greece.
9. Olive trees grow in any light soil. They can be prone to diseases in richer soils. They like hot weather and sunny positions. Historically, farmers believed that olive trees would not grow more than 55.6 km or 34.5 miles from the sea.
10. There are olive trees alive today which are over 2,000 years old. While cold weather can seem to kill the trees, the roots often survive and will sprout again in spring. If properly pruned and cared for, ancient trees can still produce fruit.