If you ever read any recipe or instructions that deal with boiling water, they always recommend that you use cold water to begin with. When I was younger I had always wondered about this. Since I am going to boil the water, wouldn’t it make more sense to get the water to boil quicker and start with hot water?
Surprisingly, the answer is no. There are two main reasons you should start the boiling process with cold water and this doesn’t only apply to tea, but any type of food or beverage you are making that requires boiling water.
Reason #1: Your hot water heater doesn’t taste good
Cold water is something that we get from the pipes that lead to our houses. In the most basic sense, when we turn on the faucet we get a fresh surge of cold water from the local water plant.
But hot water we always keep a large amount of in our hot water heaters. For those who don’t know what a hot water heater is, it is the giant barrel looking thing that is usually in a basement or utility closet. The thing about the hot water heater is it is made of metal.
When the water is stored in the heater, it has the potential to pick up some of the minerals that accumulate in the heater. And even if it doesn’t pick up minerals, it can pick up the metallic flavor since it is stored in an industrial grade metal.
Reason #2: There is less oxygen in hot water than cold
Oxygen plays a large role in the flavor of the water as it relates to tea. The simple rule is the more oxygen the better. As water is heated, the molecules become exited and move around more. This leads to oxygen escaping and since the hot water in your house is stored in a hot water heater for an extended period of time, a lot more oxygen is released compared to cold water that is brought to a boil.
I know what some of you scientific types are thinking. Water can only have two molecules of oxygen. After all, it is H2O. But, what I am talking about here deals with the solubility of oxygen in water and not the chemical makeup of water. So, while the chemical makeup will never change, the saturation point of oxygen in water will.
But what about those instant hot faucets found on water coolers?
The instant hot faucets are a great way to reduce the boiling time of your water. Since the water is stored in special polycarbonate jugs, it will not pick up any metallic flavors or minerals. The instant hot also immediately heats the water instead of storing hot water so the oxygen levels will be high as well. There really is no downside to using this water to fill your kettle.
There you have it. The reason why every single gravy, soup and oatmeal mix says to start with cold water. While the flavor may not mean that much of a difference in those mixes, they make a huge difference when drinking tea.
photo (top): www.flickr.com/photos/27089900@N00/2834643153
photo (Bottom Right): www.flickr.com/photos/faberzeus/4655745123