How Does A Clay Bottle Keep The Water Cool?

BY Madhumitha Udaykumar

Have you ever had a drink of cool refreshing water from The Indus Valley’s Clay Water Bottle? You will be surprised how pleasantly cool the water will be, despite the blazing hot temperature outside.

Terracotta Clay bottle with green cork - The Indus Valley

How is that possible?

EVAPORATION!

When water changes to water vapour without boiling, it is known as evaporation. All clay products are made of mud. It naturally has many tiny pores (extremely small holes). Even with The Indus Valley’s advance manufacturing methods – these pores remain.

Water comes out through these pores. Due to the heat from the liquid within the bottle, it gets evaporated. Thus, it cools the water in the bottle / pot.

Why does this not happen in other bottles?

Glass, plastic and metal are completely non-porous. So the water placed inside glass and metal vessels cannot seep out and evaporate. Therefore, the water inside remains hot.

Are there similar cooling methods in nature?

YES- Sweating!!!

In nature, there are a lot of processes that work in the same way as a clay pot / water bottle. Here are two most common examples:

We feel cool under a fan. The sweat from our skin pores, evaporate in the fan’s breeze. It absorbs the heat from our body to evaporate, thus making us feel cool.

All dogs hang out their tongue when they feel hot. The saliva on its tongue evaporates and the tongue becomes cooler. In turn, the dog also feels cooler.

How much water is normal? Typically clay has a porosity of upto 15%. This means if you buy our 1300 ml water bottle, it will sweat out upto 195 ml of water in 24 hours. This is normal and you need not panic.

This is the magic that cools your water naturally.