[Stoves] The PROTOS Plant Oil Cooker

[Peter Verhaart]

Dear A.D.,

If cooking oil can be overheated, doesn't that mean its boiling point 
was not reached while food was being fried in it?
The kitchen walls getting coated with oil could be from spray resulting 
from the frying process.
A test would be to heat the oil in a vessel where there is no access to 
air and see if it disappears without leaving a deposit.
If cooking oil has a boiling point how can it be overheated in an open 
pan when it remains at atmospheric pressure?
If it leaves a deposit that would mean it is undistillable at 
atmospheric pressure.

With kind regards,

Peter Verhaart


adkarve wrote:
> Dear Peter,
> I don't know if the oil would vanish without a trace. There are other
> thermochemical reactions that occur in oil at high temperature. One of them
> is the formation of epoxides. In deep frying, the substance that is supposed
> to be fried contains water. Every time you introduce something into the pan
> for frying, the temperature of the oil drops because firstly, the substance
> to be fried is at room temperature. Secondly, the water in the substance
> evaporates. The evaporation removes heat from the oil. To compensate for
> these losses the flame intensity is deliberately kept high. If the housewife
> stops introducing new material into the frying pan at a regular interval,
> the oil gets overheated. Overheated cooking oil pyrolyses. To test, if
> boiling oil would vanish without a trace, one would have to have a
> thermostatically controlled apparatus, in which the pan is kept constantly
> at 250 C.  Some residue of the epoxides and other substances may remain
> behind. It is however a fact, that oil vaporizes at high temperature,
> because in Indian kitchens, where deep frying is quite common,  the kitchen
> wall directly behind the stove, and in case one has an exhaust fan in the
> kitchen, the blades of the fan too get an oily coating.
> Yours
> A.D.Karve