The "Olive production manual" from the University of California is
a most useful publication. One of the few things is gets in a muddle about
is oil percentages and it is a pity if Oz and NZ growers have been using it
as a bible for their business plans. On page 144 it gives a table of
varieties (mostly table ones) with their oil percentages. The give away is
the footnote which says the fruit were "picked black in December through
Febuary".

The significant oil percentage is the one that occurs at the point
of maximum oil yield. After this the percentage oil continues to rise due
to WATER LOSS. The yield of oil from the grove does not increase as the
increase in percentage oil is offset by a reduction in fresh weight. For a
couple of weeks they are in balance but then the weight of fresh fruit
weight declines faster than the increase in percentage oil because of fruit
fall.

The important date is the "point of maximum yield". In our zone
this is about 23 - 25 November (May in Oz and NZ) and varies from zone to
zone but not much from year to year. The oil percentage at the point of
maximum yield is different each year. (See the January issue of the
Australian olive grower for the variation in southern Tuscany) I don't
believe the "point of maximum yield" would be as late as Febuary in
California in which case the authors have merely measured the phase of
WATER LOSS.

As far as the Manzanillo story is concerned later picking up to the
point of maximum yield will increase percentages oil and the yield from the
grove but after that will only produce a feel good factor as the real yield
of oil from the grove is declining due to fruit fall.

On a second point:-

Has anyone studied the flavor characteristics of Manzanillo in
terms of harvest date? While early picking produces better flavor all round
the different classic Umbrian and Tuscan varieties have different flavor
retention patterns with Frantoio and Moraiolo holding their flavor better
with later picking. It would be a double disaster if Manzanillo has a
Leccino style flavor graph and needs to be picked early for flavor.

If they can be grafted with another variety that could save time
but the evidence seems to be accumulating that some drastic decisions are
needed.

Cheers Brian Chatterton.

Hi,

I have been watching this debate with some interest. It seems as if it is a
debate between the traditionalists and the new agers. If one uses the
example of wine making, I live in an area in South Africa where wine and
olives are produced. Back to my example, if the wine industry had not taken
advantage of modern technology and new ideas we would still be in the wine
stone age, we would have missed out on some beautiful new blends and
cultivars. So why not with olive oil. Don't get me wrong I am not advocating
some awful chemical process for extracting oil. All I am saying is lets
think laterally for a change, its not sufficient to say "The Europeans have
always done it that way so why change"

Regards

Mike and Julie (Olive oil pressers)

-----Original Message-----
From: Brian Chatterton [mailto:tn7685@orvienet.it]
Sent: 19 June 2000 09:11
To: Olive List
Subject: [OliveOil] Oil percentage


Robin,

Quite a list of questions!!

As far as Q 1 is concerned measuring the oil percentage as one does the
sugar in grapes is not a useful means of determining the date for
picking. If you get the Australian Olive Grower you will see in the
January issue the results of trials in the Provincia of Grosseto (page
21) where the percentage of oil varied by something like 5% from year to
year from the same plot of olives that is from 18.2% to 23.5%. for
unirrigated Frantoio.


The same problem occurs with extraction. We have been advised not to
seek the highest possible oil percentage as this will require heat etc
which will reduce the quality of the oil. In Italy I do not know of any
growers who have their olives "tested" in the same way as we had our
grapes tested in the Barossa Valley.

The most important aspect of determining harvest date is fruit fall. We
have described it in our book but it does seem to be too simple for
growers in Oz and NZ to accept!! They believe there must be a more
comlex formula based on oil percentage, colour etc.

Cheers Brian Chatterton.

Dear Mike:
I agree with you.

It is interesting but we forget sometimes that the European old traditional
ways were considered to be modern at a certain time. Although I get
terrified just to the thought of "wine "coolers" (some kind of terrible
potion that advertisers use as a way of torturing me when I watch the TV
news) lets not forget that the ancient Greeks and the Romans use to mix
their wine with water or fruit juices or pine raisin (see retsina). I am
sure that there was a time when having wine along was considered modern and
revolutionaty!

I like the old ways. Not only as a matter of technique but as a way of life
and as part of a Nation's culture.

Regards,
Constantine


>From: "Mike Meredith" <mike@riebeek-kasteel.co.za>
>Reply-To: OliveOil@egroups.com
>To: <OliveOil@egroups.com>
>Subject: [OliveOil] RE: [Olive Oil] Oil percentage
>Date: Sun, 18 Jun 2000 10:18:03 +0200
>
>Hi,
>
>I have been watching this debate with some interest. It seems as if it is a
>debate between the traditionalists and the new agers. If one uses the
>example of wine making, I live in an area in South Africa where wine and
>olives are produced. Back to my example, if the wine industry had not taken
>advantage of modern technology and new ideas we would still be in the wine
>stone age, we would have missed out on some beautiful new blends and
>cultivars. So why not with olive oil. Don't get me wrong I am not
>advocating
>some awful chemical process for extracting oil. All I am saying is lets
>think laterally for a change, its not sufficient to say "The Europeans have
>always done it that way so why change"
>
>Regards
>
>Mike and Julie (Olive oil pressers)
>
>-----Original Message-----
>From: Brian Chatterton [mailto:tn7685@orvienet.it]
>Sent: 19 June 2000 09:11
>To: Olive List
>Subject: [OliveOil] Oil percentage
>
>
>Robin,
>
>Quite a list of questions!!
>
>As far as Q 1 is concerned measuring the oil percentage as one does the
>sugar in grapes is not a useful means of determining the date for
>picking. If you get the Australian Olive Grower you will see in the
>January issue the results of trials in the Provincia of Grosseto (page
>21) where the percentage of oil varied by something like 5% from year to
>year from the same plot of olives that is from 18.2% to 23.5%. for
>unirrigated Frantoio.
>
>
>The same problem occurs with extraction. We have been advised not to
>seek the highest possible oil percentage as this will require heat etc
>which will reduce the quality of the oil. In Italy I do not know of any
>growers who have their olives "tested" in the same way as we had our
>grapes tested in the Barossa Valley.
>
>The most important aspect of determining harvest date is fruit fall. We
>have described it in our book but it does seem to be too simple for
>growers in Oz and NZ to accept!! They believe there must be a more
>comlex formula based on oil percentage, colour etc.
>
>Cheers Brian Chatterton.

Dear Constantine,

I am not knocking the old ways, and I am not suggesting that we do away with
them. I just feel that we should try new ways as well

Regards

Mike

-----Original Message-----
From: Constantine Alexander [mailto:papashaven@hotmail.com]
Sent: 18 June 2000 17:28
To: OliveOil@egroups.com
Subject: Re: [OliveOil] RE: [Olive Oil] Oil percentage


Dear Mike:

I agree with you.

It is interesting but we forget sometimes that the European old traditional
ways were considered to be modern at a certain time. Although I get
terrified just to the thought of "wine "coolers" (some kind of terrible
potion that advertisers use as a way of torturing me when I watch the TV
news) lets not forget that the ancient Greeks and the Romans use to mix
their wine with water or fruit juices or pine raisin (see retsina). I am
sure that there was a time when having wine along was considered modern and
revolutionaty!

I like the old ways. Not only as a matter of technique but as a way of life
and as part of a Nation's culture.

Regards,
Constantine


>From: "Mike Meredith" <mike@riebeek-kasteel.co.za>
>Reply-To: OliveOil@egroups.com
>To: <OliveOil@egroups.com>
>Subject: [OliveOil] RE: [Olive Oil] Oil percentage
>Date: Sun, 18 Jun 2000 10:18:03 +0200
>
>Hi,
>
>I have been watching this debate with some interest. It seems as if it is a
>debate between the traditionalists and the new agers. If one uses the
>example of wine making, I live in an area in South Africa where wine and
>olives are produced. Back to my example, if the wine industry had not taken
>advantage of modern technology and new ideas we would still be in the wine
>stone age, we would have missed out on some beautiful new blends and
>cultivars. So why not with olive oil. Don't get me wrong I am not
>advocating
>some awful chemical process for extracting oil. All I am saying is lets
>think laterally for a change, its not sufficient to say "The Europeans have
>always done it that way so why change"
>
>Regards
>
>Mike and Julie (Olive oil pressers)
>
>-----Original Message-----
>From: Brian Chatterton [mailto:tn7685@orvienet.it]
>Sent: 19 June 2000 09:11
>To: Olive List
>Subject: [OliveOil] Oil percentage
>
>
>Robin,
>
>Quite a list of questions!!
>
>As far as Q 1 is concerned measuring the oil percentage as one does the
>sugar in grapes is not a useful means of determining the date for
>picking. If you get the Australian Olive Grower you will see in the
>January issue the results of trials in the Provincia of Grosseto (page
>21) where the percentage of oil varied by something like 5% from year to
>year from the same plot of olives that is from 18.2% to 23.5%. for
>unirrigated Frantoio.
>
>
>The same problem occurs with extraction. We have been advised not to
>seek the highest possible oil percentage as this will require heat etc
>which will reduce the quality of the oil. In Italy I do not know of any
>growers who have their olives "tested" in the same way as we had our
>grapes tested in the Barossa Valley.
>
>The most important aspect of determining harvest date is fruit fall. We
>have described it in our book but it does seem to be too simple for
>growers in Oz and NZ to accept!! They believe there must be a more
>comlex formula based on oil percentage, colour etc.
>
>Cheers Brian Chatterton.

Robin,

Quite a list of questions!!

As far as Q 1 is concerned measuring the oil percentage as one does the
sugar in grapes is not a useful means of determining the date for
picking. If you get the Australian Olive Grower you will see in the
January issue the results of trials in the Provincia of Grosseto (page
21) where the percentage of oil varied by something like 5% from year to
year from the same plot of olives that is from 18.2% to 23.5%. for
unirrigated Frantoio.


The same problem occurs with extraction. We have been advised not to
seek the highest possible oil percentage as this will require heat etc
which will reduce the quality of the oil. In Italy I do not know of any
growers who have their olives "tested" in the same way as we had our
grapes tested in the Barossa Valley.

The most important aspect of determining harvest date is fruit fall. We
have described it in our book but it does seem to be too simple for
growers in Oz and NZ to accept!! They believe there must be a more
comlex formula based on oil percentage, colour etc.

Cheers Brian Chatterton.

I agree with Michael about the over the top description of oil such as
"fresh grass, fresh mown-hay, young fresh artichokes, almonds, supple,
unctuous with a peppery finish," but that is about all I agree with. In
any case you cannot blame the grower for the way the oil is described.

The most common reason for low oil percentages is that the variety is a
table one or a so called dual purpose olive. In that sense low quality
and low oil percentage are linked but that is a correlation not a
cause. If one waited for the oil percentage to rise (the yield of oil
would fall) the quality would not improve.

Elsewhere oil percentages for real oil varieties are a factor of
climate - (cool climates in mountain areas produce lower percentages)
the season - (there is a five percent variation from season to season)
and the time of picking. Early picking certain means that percentages
are lower. I completely disagree that leaving the olives until half
have dropped on the ground and the other half have shriveled does
anything for quality. In crude terms the acidity has risen but just as
important the flavor is bland as the olives are so over ripe.

Cheers Brian Chatterton