|Distilled water is produced by a process of distillation, and has an
electrical conductivity of not more than 10 µS/cm and total dissolved
solids of less than 10 mg/liter.
Distillation involves boiling the water and then condensing the vapor
into a clean container, leaving solid contaminants behind.
Distillation produces very pure water.
A white or yellowish mineral scale is left in the distillation
apparatus, which requires regular cleaning.
Distillation alone does not guarantee the absence of bacteria in
drinking water unless containers are also sterilized.
Double-distilled water (abbreviated "ddH2O", "Bidest water" or "DDW") is
prepared by double distillation of water.
Historically, it was the de facto standard for highly purified
laboratory water for biochemistry,
and trace analysis until combination methods of purification became
For many applications, cheaper alternatives such as deionized water are
used in place of distilled water.
Deionized water, also known as de-mineralized water (DI water, DIW or
de-ionized water), is water that has had its mineral ions removed,
such as cations from sodium, calcium, iron, copper and anions such as
chloride and bromide.
Deionization is a physical process which uses specially-manufactured
ion-exchange resins which bind to and filter out the mineral salts from
Because the majority of water impurities are dissolved salts,
deionization produces a high purity water that is generally similar to
and the process is quick, and without scale buildup.
Deionization does not significantly remove uncharged organic molecules,
viruses or bacteria, except by incidental trapping in the resin.
Specially made strong base anion resins can remove Gram-negative
Deionization can be done continuously, and inexpensively using
Deionization does not remove the hydroxide OH- or hydronium H+ ions from
These are the products of the self-ionization of water to equilibrium
and therefore are impossible to remove.
Start with a pot with a standard steamer insert:
Fill the pot with water, to a level just below the bottom of the steamer
insert, when inserted.
Side view showing pot with steamer insert placed on top
Place a bowl in the bottom center of the steamer insert:
Allow room around the sides for the steam to rise around the bowl.
Bring the pot to a boil, and wait until you have a good boil going, and you
are producing steam.
This will insure that anything that boils below the boiling point of water is
boiled off first.
Place the lid on top of the steamer insert inverted / upside down, so that it
a low spot in the center where condensation will accumulate and drip from,
into the bowl.
Place Ice on top of the lid, to cool the lid promoting condensation.
Scoop water out of the lid with an appropriate sized spoon, and replace
melted ice as necessary.
Some water is OK, but you do not want it to overflow. I keep it about 1/2 to
2/3 of the lid volume.
Draw water from the outside edge with the spoon, where water is the hottest,
not the cold water from the center, around the ice.
After about 4 trays of Ice (a little over an hour later) you should have
about 12 ounces of distilled water in the bowl.
Here is what it looks like:
This will be absolutely PURE Water, with nothing in it but WATER!!!
Allow everything to cool, as everything WILL BE HOT!!!
Once everything is cool, carefully slide the bowl to one side,
so that you can get your fingers in to grip one side of the bowl.
Carefully lift the bowl out. Try not to spill the distilled water.