The olive is the fruit of the olive tree and thrives around the Mediterranean. In favorable and sheltered locations, an olive tree can also develop fruit in this country, although the harvest is usually rather sparse. It takes several years before these stone fruits can be harvested for the first time. Green and black olives are commercially available. These are by no means different varieties, but different degrees of ripeness that determine the harvest time.
harvest time
Harvest time for olives
The ripening process of these coveted stone fruits is determined by the prevailing temperatures, the number of hours of sunshine, the right watering and, last but not least, the respective variety. They can be harvested when they are unripe or left to ripen on the olive tree. Until then, the fruit goes through three stages of ripening.
early stage
Initially, every olive is green, regardless of the variety. If harvested at this early stage, it will keep its green colour. At this time it contains significantly more bitter substances than when ripe. Green olives are mainly used to produce high-quality olive oil. The younger these stone fruits are, the higher their content of so-called polyphenols.
These are valuable plant ingredients and an important quality feature in olive oils. In contrast, they contain only about a third of the oil content of fully ripened ones. For the production of olive oil, about three times as many green olives are needed as ripe ones. Unripe, they have a very intense and bitter taste and are usually inedible.
Progressive Maturity
After 2 - 3 months, the green fruit slowly changes color to yellowish-green and then to a reddish-purple hue. The taste and consistency change as it matures. The aroma becomes milder and, in addition to the bitterness, a certain spiciness also develops. The flesh will gradually soften. With increasing ripeness, the proportion of polyphenols also decreases, although it is still relatively high at this stage of ripening.
final stage
If you leave them hanging on the tree long enough, they turn jet black. Not only have they turned black on the outside, the flesh inside and even the core are black through and through. The ripening process is complete and you can harvest.
- When ripe, these stone fruits contain significantly less bitter substances
- the content of polyphenols has continued to decrease
- not much left of the once bitter and pungent taste
- they now have a rather sweet note
- they now contain more monosaturated fat and are higher in calories
- the oils made from fully ripe olives are more golden in colour
- Color may vary slightly from variety to variety
- Shelf life of these oils is significantly lower than that of unripe olives
Obviously fully ripe olives from the trade are usually only ripe at first glance. However, the black coloring is often not a sign that they have ripened on the tree. They were harvested unripe, i.e. green, and then colored black with iron(II) gluconate (E 579). Treated in this way, they have a longer shelf life and their taste also changes. If they have been blackened in this way, this must be indicated on the packaging.
Tip: It is usually easy to tell whether the black fruits that you can buy in stores are blackened or have ripened on the tree. While naturally ripened are deep black from the skin to the core, blackened ones are only black on the outside.
pollination
No flowering without pollination
Only when the olive tree has blossomed and the blossoms have been fertilized can it produce fruit. The flowers of these trees are among the smallest of the Mediterranean plants. Pollination is usually done by the wind. In order to create the best conditions for the formation of flowers and fruits, you can also pollinate yourself.
To do this, transfer the pollen from one plant to the other with a soft brush. Nevertheless, it takes about seven years until the first flowering. The highest yields are only achieved after about 20 years. The time of harvest varies depending on the variety, location and desired degree of ripeness. The harvest usually takes place between October and March.
bitter substances
Remove the bitter substances from the fruit
Although tempting, do not eat fresh olives straight from the tree, they will taste very bitter. In order to make them edible, you first have to remove the bitter substances from them.
- Score the ends with a sharp knife
- then soak in pure water
- they should be completely covered with water
- Renew or change the water daily until it remains clear
- it can take about four weeks for the bitter substances to be flushed out
- when the bitter taste is gone, soak in brine for another week
- Make brine from 1 liter of water and about 7 tablespoons
- Afterwards, depending on your personal taste, place them in marinades made from olive oil
Olive harvest in this country
Difficult olive harvest in Germany
In Germany, the olive tree is mainly kept as an ornamental tree. Under optimal conditions, however, it can also develop flowers and fruits here. This is most likely to succeed in warm regions with a wine-growing climate deep in the south. There have been experimental olive groves in Germany for a long time, but so far without any significant yields. The biggest problem is the prevailing climatic conditions in this country, especially in winter.
From spring to autumn, the plants can soak up the sun outside. For the winter they need an appropriate winter quarters. If they feel completely well, they will also blossom. The fruits usually ripen in autumn. They can be harvested from around November, provided they ripen at all and don't fall off the olive tree before then. Even if most of our olive trees do not bear fruit, they are a great eye-catcher even without them.