There are hundreds of different varieties of olive trees. Some are very similar, sometimes identical with just slightly different names. Some are very different. They have different looks as well as growing characteristics and preferences. Their olives vary in size, oil content, taste, chemical characteristics, ripening time, and many other factors.
The four main varieties of olives grown in California used to be: Mission - originally cultivated by the Franciscan missions; Manzanillo - the most prevalent; Sevillano and Ascolano - the larger sizes. There is now a very wide diversity of olives found in California.
We recommend reading the "Olive Varieties" section on pages 7, 8, and 9 in Paul Vossen's book, Organic Olive Production Manual, University of California. It provides an excellent description of the most common varieties.
OLIVE VARIETAL IDENTIFICATION
Differences between the thousands of varieties can be very subtle. It is now possible to use DNA fingerprinting to identify specific varieties. Some of the laboratories listed on our Testing Laboratories page provide this service.
Researchers at the two World Olive Germplasm Banks (Córdoba & Tassaout-Marrakech) are doing on-going research on the determination and description of the genetic make-up of the olive species.
INFLUENCE OF VARIETY ON OLIVE OIL QUALITY
Variety, along with maturity are the two most important factors on the quality and taste of olive oil. Click here to see what Paul Vossen, the leading California expert on olive oil, has to say.
Where can I go to find scientific information about olive varietals?The Olive Oil Source has produced a Varietal Chart.
More information about olive varietals can be found at the OLEA database and the International Olive Oil Council.