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<pre>Dear Guido,

When I posted my views on cold pressed olive oil I introduced myself
and qualified my position by my professional experience and
reputation. I am new in the list and you have to forgive me if I do
not recognize your name. It is only fair to ask for my self as well
as the rest of participants who care about this issue, to know what
substance the views which here expressed, carry.
So please, identify who you are and to whom are you refering to, when
you state: "the sogginess of the solid waste from the two-phase
systems is not an issue for us" ( "us" is your company? Your area?
Your region? Your country?).

I will wait for your answer and then I will address each and every
one of the points you are making in your Nov 13 e-mail.

Kind regards
George



--- In OliveOil@y..., "Guido Costa" <costa@m...> wrote:
> George, I must take issue with you on a number of points:
>
> Firstly, the "two-phase" centrifuge was introduced primarily to
reduce the
> problem of the water-soluble polyphenols being leached from the
oil. This
> was certainly a drawback of the old three-phase systems, which not
only
> created substantial soluble waste, but detracted from the quality
and
> character of the oil (not to mention the water consumption).
>
> However, your statement that most "two-phase" systems are being run
as
> "three-phase" is rather sweping. Not all olive oil producers are
involved in
> producing olio sansa (pomace oil), and thus the soggyness of the
solid waste
> from the two-phase systems is not an issue for us.
>
> Obviously you chaps have a pomace oil industry to support. I
sincerely hope
> you reserve this oil only for making soap and candles. The
worldwide problem
> of benzo-alpha-pyrene contaminant in pomace oil (the carcinogenic,
> genotoxic, neurotoxic compound found in many of these residue oils)
most
> probably originates from the aggressive drying of this soggy pomace
or sansa
> (prior to the solvent extraction stage). BaP is a Polycyclic
Aromatic
> Hydrocarbon, which is formed during the incomplete burning of
organic
> matter, and has been found in pomace oils from all major producer
countries,
> including those from Greece (at up to 60 times the maximum
permissible
> level).
>
> I'm sure that there are many producers out there, who, like
ourselves, are
> not involved in producing olive pomace oil, and who are operating
their
> systems the way they were designed to operate.
>
> Over the last 70-odd years, we have used hydraulic presses, surface-
tension
> extraction systems and continuous decanters. To my mind, based on
our
> specific experience, there is nothing to touch the modern, well-
designed
> decanter (or centrifuge). It is a far more hygienic system, easy to
clean,
> and to keep clean. But like any other system, must be operated
properly. We
> run our system such that the pulp never exceeds 28 degrees C, nor
do we
> churn the pulp unduly. Whether the oil is pressed out by pressure or
> centrifugal force is not the issue. The problem with the presses is
that it
> is virtually impossible to keep the press mats clean. Unless one
very
> vigourously steam-cleans the mats after every pressing (and this is
totally
> impractical), one is bound to be building up a contamination of
steadily
> increasing rancidity and other off-flavours in the mats. Try
looking at the
> mat fibres under a microscope, and see what I mean. Or just smell
the mats
> in many of these hard-core traditionalist mills.
>
> As far as I am concerned, the debate is not between presses and
centrifuges,
> but between stone mills and hammer mills. Both have advantages and
> disadvantages, and I'm not yet convinced, although the new
hammermills seem
> to be improving rapidly. It would be interesting to hear from those
that
> have experience in both.
>
> Regards,
>
> Guido Costa
</pre>
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