Distilled water is created through a process that mimics the Earth’s natural water cycle, purifying water by boiling and condensation. This method involves heating tap water until it converts into steam, leaving behind nearly all dissolved solids and impurities. When the steam cools and returns to a liquid state, the resulting water, known as distillate, is remarkably pure, often containing less than 10 parts per million of total dissolved solids. Tap water contains various minerals, salts, and trace contaminants that can cause problems in specific applications. Home distillation offers a reliable way to produce water free of these elements for household needs.
Applications of Distilled Water
The primary benefit of distilled water is its lack of mineral content, which prevents the buildup of scale and deposits in many devices. This makes it useful in equipment that relies on heating or humidifying water, such as steam irons and humidifiers. Regular tap water in these devices can leave behind a white, crusty residue, which reduces efficiency and lifespan.
Distilled water is the preferred source for medical devices like Continuous Positive Airway Pressure (CPAP) machines, as its purity prevents microorganism growth and mineral deposition. It is also specified for use in automotive applications, such as topping off lead-acid batteries and mixing with engine coolants. The absence of ions prevents corrosion and interference with electrical processes in these applications. Its purity makes it the standard for sensitive laboratory work and many cosmetic formulations.
Step-by-Step Home Distillation Method
To begin the process, gather a large pot, a clean, heat-safe glass or metal collection bowl that fits inside, a concave lid, and ice. Fill the large pot about halfway with tap water, ensuring the water level is below where the collection bowl will sit. Place the collection bowl inside the pot, either floating on the water or resting on a raised, heat-safe rack.
Next, place the lid upside-down on the pot so the center of the inverted lid is positioned directly over the collection bowl. The concave shape of the inverted lid funnels the condensing water vapor toward the center. Turn the burner to a medium-low setting to bring the water to a gentle, steady simmer, avoiding a vigorous boil. A rapid boil produces excessive steam that is difficult to condense and may splatter contaminants into the collection bowl.
Once the water is simmering, place ice cubes or an ice pack directly onto the inverted lid. The significant temperature difference between the steam and the cold surface rapidly promotes condensation. The water vapor will condense on the underside of the lid, trickle down the curved surface, and drip into the collection bowl.
Continue this process, replacing the ice as it melts, until you have collected enough distilled water. The distillation process is slow, typically yielding about one cup of distillate per hour of gentle simmering. Once finished, carefully turn off the heat and allow the pot to cool slightly to minimize steam burns. Then, remove the lid and the collection bowl; the water inside is your finished distilled product, while concentrated impurities remain in the large pot.
Safety and Purity Considerations
Working with boiling water and steam requires careful attention to safety to prevent scalding. Always use oven mitts or heat-safe grips when handling the hot pot, lid, and collection bowl. Ensure the work area has good ventilation, as home distillation may not completely remove all volatile organic compounds (VOCs) that can vaporize with the water.
Use a collection container made of glass or stainless steel, as the pure nature of distilled water can leach trace chemicals from certain plastics. While this household method removes nearly all non-volatile contaminants and minerals, the resulting water may not meet the standards of commercially produced, laboratory-grade distilled water. Therefore, homemade distilled water is best suited for general household and appliance use. Discard the first small amount of distillate to clear any lingering residue from the equipment.