>> On 10 Feb 1999, Carol wrote:
>>
>
>>> > I've heard that oils that are labeled as "cold-pressed" experience
>>> > very high temperatures in the pressing process anyway, because of
>>> > the extreme friction involved, but that the makers are able to say
>>> > "cold" because they don't add heat on purpose. This sounds pretty
>>> > likely to me. What do other folks think?

Jean-Louis Tu wrote:

>>
>> I just read on a bottle of "Bjorg" sunflower oil:
>>
>> "[The oil] is cold-pressed (T<60°)"
>>
>> Notes:
>> * 60 deg C = 140 deg F
>> * I don't know about other types or brands of oils
>> * I suspect that at these temperatures, there is very little
>> denaturation, and that proper storage conditions are more important
>> than the temperature reached during extraction.


Carol:
Nice of the Bjorg folks to get specific! As for the effect of such
heat during extraction, I would guess that it varies widely with the
type of oil being so exposed, and I think one can probably get a good
idea of a particular oil's level of fragility by looking at the storage
instructions. If I remember right, sunflower is one of the toughest
ones, able to stay at room temperature for months, while others (such
as flax) shouldn't be out of the refrigerator for more than a moment.
(Even in the refrigerator, it doesn't last long.)

Tricky stuff, oil. :)