Using the recently proposed open-photoacoustic-cell (OPC) detection technique the thermal diffusivity of potato skin has been found. Skin samples were taken from potatoes that were grown on different soils. The measurements were carried out with samples that, after being removed from the potatoes, were left in the air for different periods of time. Apparently, the process of the dehydration/oxidation resulted not only in the expected shrinkage of skin layers but also entailed chemical and/or structural changes that have produced a noticeable decrease of the thermal diffusivity coefficient.