We finished our harvest a few days ago. The percentage oil was 14 to 15%
for different batches.
The talk at the frantoio was that percentages were low this year.
That was not our experience. While we have had 18 and 20% the average is in
the 14 to 15% range.

Some of the growers blamed the wet autumn. However the rainfall
records do not show that the autumn has been particularly wet. The October
figure has been boosted by one fall of 143 mm in 6 hours - but I doubt

Brian,
As far as I know, the rainfall distribution is far more important than the quantum, assuming a reasonable season. If the rain fall is during the time at which the seed is forming and before hardening, the seed will be larger than "usual". If, then, there is a lack of rainfall during the time following seed hardening (which is the time of flesh cell development) there will be little oil in the fruit. The oil accumulates as the flesh develops (both by cell division = multiplication, and b y cell enlargement) so if there is not enough rain then, the oil yield will be poor.