Distillation and demineralisation are both forms of purifying water but they have different methods of achieving this purification. The two methods do produce different results and it is worth looking into both so that you are equipped with the knowledge of the differences between them.
Distilled water simply refers to water that has undergone a process where the water is heated to above boiling point and the steam from that water is captured and cooled to produce liquid distilled water. This type of the purification process is the most common method and the end result is a very pure product. This method removes bacteria, organic and inorganic particles, viruses, minerals, etc. from the water and once the water has gone through this process, must be stored in a sterilised container so to maintain its purity. The distillation process also removes salts, metals, and minerals.
There can be volatile organic compounds and gases that make their way through the distillation process due to these compounds having a lower boiling point to water. Usually, manufacturers will add in extra filtering processes to absorb any remaining compounds and gases.
Demineralised water is a more economical means of water purification and simply refers to any water that has undergone a process to remove minerals and salts from the water. This type of water is used in applications where water with low salt content or low conductivity is required. Demineralised water is made by passing the water through specially manufactured resins. The resin is designed to exchange ions in the water so that the final result leaves you with the chemical composition of pure water.
While demineralised water is virtually free from minerals and related substances, there can be very tiny amounts of dissolved minerals that will always remain. However, the advancements in technology for demineralisation ensure the end result is very high quality water.
What is the Difference Between Distilled and Demineralised Water?
Distilled and demineralised water are produced through different methods of purification and as such, produce a different end result. Demineralised water has had minerals removed so that you are left with H2O. The problem with demineralisation is that it will not remove bacteria or viruses like distilling would. Distillation is a very effective method and will remove 99.9% of contaminants.
Simply put, where distillation is effective at removing suspended particles, organic materials, bacteria, viruses, and physical impurities, demineralisation is not. Distillation is a much more effective method of purifying the water.
Many manufacturers these days will actually put the water through both purification methods to ensure you get as pure water as possible. The reason for this is that the demineralisation process removes trace elements that manage to make their way through the distillation process.