The Water Stored in an Earthen pot is cool. The pot is made of Natural Terracotta Clay and The clay is porous. So due to minor pores in the clay, The water stored inside the pot percolates into the pores and as a result, oozes out of the pot in the form of droplets. These droplets absorb the heat of the water stored and evaporate resulting into cooling of water. While many a times the Water accumulates at the bottom. It is a Natural Phenomenon.
Porosity Level of Pots
The Porosity Level of each and every Pot is different from each other. The pots with Same Design, Same Shape, Same size, Same Batch have different porosity Level. i.e. Pots with Higher Porosity Level ooze higher amount of water compared to the ones with lower porosity level. As porosity Level is totally natural and not in human hands, It can not be controlled. But the oozing of water signifies the pot to be non-colored.