Expert: Dana Krempels, Ph.D. - 4/11/2008

Question
Hello Dana. It is possible to product olive oil from black olives? All the olive oil I have ever seen is green

Answer
Dear Barnaba,

From our old pal, Wikipedia:

"The most traditional way of making olive oil is by grinding olives. Green olives produce bitter oil, and overly ripened olives produce rancid oil, so care is taken to make sure the olives are perfectly ripened. First the olives are ground into an olive paste using large millstones. The olive paste generally stays under the stones for 30–40 minutes. The oil collected during this part of the process is called virgin oil. After grinding, the olive paste is spread on fibre disks, which are stacked on top of each other, then placed into the press. Pressure is then applied onto the disk to further separate the oil from the paste. This second step produces a lower grade of oil."

I assume that the second sentence means that olive oil is extracted only from ripe, black olives, even though the oil itself has a greenish color.

(We both learned something today!)  :)

Dana