Removes oxygen from boiling water

What difference does the oxygen content of tea water make?

I've heard the advice that water should only be boiled for tea - when boiled it loses dissolved oxygen, and if the water doesn't contain enough oxygen it will (somehow) affect the taste of the tea.

That doesn't seem to make sense to me. If the water loses oxygen while boiling, it would have lost it before the tea ever touched it.

Does that really make a difference, or is it just a common kitchen myth? If there is, what influence does the oxygen (or deficiency) have on the finished product?


This blog article (citing numerous sources) claims that reboiling water does not significantly affect the taste of tea. Here are some key points of it:

  • When water is heated above 50 ° C, most of the oxygen is removed, so that neither once boiled nor twice boiled water contains significant amounts of oxygen.

  • Triangle tests like this one prove that dissolved oxygen itself does not affect the taste of water.

  • While oxygen could theoretically reduce the concentration of tannins in tea, this effect is dwarfed by other factors, notably soaking time, water temperature, and water / tea ratio.

All of this is not to say that water is unimportant. Water is important. Alkalinity is important. Salinity is important. Minimum iron content is super important. Dissolved oxygen is not important. [...] Dissolved gases are irrelevant for the preparation of tea, coffee or other hot drinks.

All flowing water has oxygen dissolved in it. This is what fish breathes

Dissolved oxygen is reactive and most likely extracts more substances from the tea leaf than without it. I don't know if these are the good taste parts of the tea?

When you heat water, the dissolved oxygen is released. The more you heat water, the more oxygen escapes

You can buy tea makers that will bring water to 95 ° C but not boil it to reduce the loss of dissolved oxygen, but still make the water hot enough to make tea. They also save energy :-) I use one of these and am happy with it

Example kettle

Some people "look" their kettle and turn it off just before the water boils!

Whether or not tea tastes better in water with more dissolved oxygen is a personal taste preference

I agree with your suspicions. Most likely during boiling water does because it is losing some of its oxygen supply, the bubbles and steam you see while boiling water is not coming from the oxygen trapped in the water.

Water boils when you heat it so much that the water acts as a gas. The reason boiling water gushes is because the heat source is generally at the bottom, so the first molecules of water to turn into gaseous form are at the bottom and then gush.

To say that boiling water releases its internal oxygen is akin to saying that ice is not water and, in fact, simply traps water inside.

If you are concerned about your oxygen supply, there are several ways to pour your cup of tea:

  1. cook in the cup (microwave?)
  2. boil, then pour into a cup
  3. cook then pour into a cup a few times
  4. Take a straw and blow a few bubbles into your cup
  5. try seltzer water to make tea ...?

Anyway, I could be wrong, but the whole concept seems a little silly.

Drink happy tea:]

My mother, who would have been 100 years old by now, always told us that boiling the water made the water taste a bit "stale". She talked about "Free Oxygen" which I think was her way of saying "Dissolved Oxygen". I think DO is what fish actually get through their gills, which is why fish in a bowl need fresh water (with DO in sufficient quantities) to live. So - my theory is that tea is best made with fresh water that hasn't been boiled beforehand. That's my 2 cents!

All correspondents seemed to have misplaced chemistry and physics from early school classes, as I remember that water is made up of two atoms of hydrogen and one atom of oxygen, if you were to remove the oxygen as suggested to make sure we had H2, that What is left NTP (normal temperature and pressure) is a highly flammable gas. A chemical reaction (catalysis) or electrolysis is also required to separate O from H2. Boiling water simply heats water until the vapor given off equals atmospheric bar or an atmosphere in old money, for the sake of interest, Marks and Spencers have a note on their tea packages that boiling water removes the oxygen, a case I do consider appropriate law enforcement.

Tom Gilmore

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