There are two types of alkali water that are available.

One is spring water that has increased its pH level along its journey from mountain springs to bottles, and for a long time in the UK was the only way to find alkali water.

However, a more technologically advanced approach is available which takes advantage of water ionisers and reverse osmosis to produce the exact type of water you want.

To understand reverse osmosis, it is important to know what osmosis is, which is where water (or another solvent) tries to achieve a state of balance between two mixtures of water and other minerals, salts and sugars.

If there is a higher concentration of water to other minerals, then water will travel through a semi-permeable membrane to where there is a lower concentration of water relative to other minerals.

This is often used in the human body to regulate the concentration of water and different minerals through a complex series of semi-permeable membranes.

However, if you apply pressure, you can force water to go through this semi-permeable membrane and flow from a mixture where there is a lower concentration of water relative to salts and other minerals to one where there is less water.

This is the opposite of how osmosis works, hence the name reverse osmosis.

This is also called desalination as it is the process used to make saltwater drinkable, by forcing water through a membrane to remove not just salt, but microorganisms and pollutants that are often found in seawater.

This can also be used to create deionised water, which is used to create alkali water.