To release the tase and aromas from shisha tobacco we need to heat up the tobacco at its boiling point so that we vaporises. We do not what to burn the tobacco, rather we try to cook it to the vaporising temperature. In a traditional shisha pipe, the heating of the tobacco is not uniform. Grandually and occazionally the shisha tobacco is overheated and burned, mostly the upper part of the shisha.

This issue is obvious in the thermograph shown below. The shisha tobacco in the bowl is already burned just below where the coals where sitting while at the opposite edge of the bowl the tobacco has not even reached the vaporizing temperature.

 thermokrasia nargile

An other issue with the bowl/foil/charcoal system is the problem of the resituted coal ash and other componets from the burning coals. This gives a slight coaolish flavour (taste of coal) in the shisha and it is potentially harmful to the user. This problem is attributed to the user of perforate foil on which the coal are resting and heat the tobacco. (Εικ. 5.1-7). The air that the user inhales passes through the coals (Εικ. 5.1-3), thus, the user inhales the biproducts of charcoal burning. Further, the ashes and dust from the charcoal goes through the holes on the foil and end up at the shisha tobacco. The picture below shows the ashes at the surface of the tobacco after 1.5 hours of smoking

nargiles vortex bowl staxti