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<pre>Malaxing time is a critical factor. Ultimately the water jacket and paste
temperatures would equalise, i.e. as the water jacket temperature is
thermostatically controlled, the paste temperature would rise to the set
jacket temperature. It is therefore necessary to determine empirically (big
word for trial and error) what the correct jacket temperature should be to
achieve the desired paste temperature in the desired malaxing time.

The rate of temperature rise in the paste is proportional to the temperature
differential between the paste and the water jacket. If one wishes to bring
the paste to the desired temperature quickly and then let it malax at that
temperature for the remainder of the malaxing time, one would have to set
the jacket temperature to a high setting initially and when the paste is at
the desired temperature, reduce the jacket temperature to circa the desired
paste temperature for the remainder of the process- maybe one degree higher.

This only works if you are doing one batch at a time - if you have a double
malaxer in a continuos operation you cannot vary the setting as the water
jacket is shared.

I do not know the Pieralisi machines, but the Alfa Laval Malaxers have a
temperature probe in the outlet to the paste pump. Pretty useless if you
want to avoid overheating the paste. A good idea is an infra red surface
thermometer - it's a hand held gun that you point at the paste (or anything
else for that matter) and it gives you a digital temperature readout.

Best regards

Kurt Küpper

kupper@xtra.co.nz

-----Original Message-----
From: Andrew Brown [mailto:drewbrow@senet.com.au]
Sent: Tuesday, 12 June 2001 23:43
To: OliveOil@yahoogroups.com
Subject: Re: [OliveOil] Re: Olive yields - update


While the water jacket temperature for the Pieralisi is set to 40 deg C
there is
no guage on our machine to measure the temperature of the mash. We are
actually
looking to add a temperature guage. With 350Kg in the molaxer and the water
jacket at 40 deg C I would be surprised if the mash gets to that
temperature. I
may be wrong and time will tell once we fit a guage after the current season

Best Regards

Andrew & Val

P Caird wrote:

> > >Graeme, 'cold' extraction stands for Wagga Wagga's laboratory crushing,
> > >malaxing and pressing at temperatures not exceeding 32 deg C.
>
> I find this interesting. As most will know Pieralisi set their
temperature
> at 40C as this is, apparently, the standard to which they usually adhere
to.
> As I have noted previously, there is a distinct chocolate aroma coming
from
> the paste cooking at these temps. We do not process above 25C paste
> temperature. The paste at this temperature (depending on variety)
produces
> a delightful fruity aroma and our yields are not affected unduly or even
> significantly (previous posting 31/05/01).
>
> Now the term "cold pressed" refers to the traditional method (hydraulic)
of
> processing oil without the addition of heat. With modern centrifuges
there
> is a problem of developing a corollary to this expression (although I note
> many still use the old expression despite it's lack of accuracy). Cold
> Paste? Cold Spun? Low Temperature Processing? Emotionless Processing?
At
> what temperature can we say the oil has been cold-processed? Why 32C?
Why
> have I chosen 25C (I have good reasons, all associated with
> flavour/longevity of oil)?
>
> Of course we shall have to set aside the passion (with the implication of
> heat and fieriness) that we all have for our product but that is another
> dilemma.
>
> Regards
> Peter Caird
> www.victorianolivegroves.com
> 0418 392 157
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/


Olive Books: http://sadoun.com/olive

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<pre>This only works if you are doing one batch at a time - if you have a double
malaxer in a continuous operation you cannot vary the setting as the water
jacket is shared.

I agree with your general comments but note that both the 2x350kg chambers
are thermostatically controlled on the Pieralisi. If one wants to process
at 25C then set your thermostat for 30C (assuming a 1 hour malaxing period).

Regards
Peter Caird
www.victorianolivegroves.com
0418 392 157
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