How to Boil Water
This post will be instructing and discussing the intricacies of how to boil water for tea. The best way to boil water is one a stove using cold water but I be taking you through all the steps, thoughts, and options for boiling water.
Here are the basic directions, a detailed explanation of the theory behind each step will follow.
1) fill kettle or pot with cold water
2) bring to boil (or desired temperature)
3) pour hot water over tea.
Let’s start off by briefly talking about water.
Water is never just water, water often contains trace amounts of minerals and in the case of water from city systems, contains added chemicals like fluoride to aid in dental health. Cold water and hot water are also different. Cold water is able to hold more dissolved oxygen. Hot water contains less dissolved oxygen and is more likely to pick up trace minerals or sediment from aged water pipes. The resulting condition of your water could potentially lead to unwanted variations in your brew of tea and also cause minor changes in variations in the brew temperature and time. In conclusion, cold water is ideal from a point of food safety and water consistency.
Water is commonly heated 1 of 3 ways: on the stove, with plug-in electric kettles, and in the microwave.
Stove
Heating water over a stove (or fire) is how water has been heated all throughout human history. Gas stoves tend to be able to heat water quicker than electric stoves, however, induction stoves, which are relatively new, challenges this with quick heating times and improved user safety features. In short, heating water over a stove is a pretty reliable means to bring water to a boil and using a kettle with a whistle.....
Electric Kettle
Plug-in electric kettles are convenient and there are many models on the market with advanced features like temperature control, auto shut off, and a warm idling “keep warm” feature. I do have two concerns about plug in electric kettles: 1) is the kettle made of plastic/glass/metal? 2) wearing of the heating element.
The first point is of most concern because some plastics release unwanted chemicals into water and food that comes in contact with it. However, this usually takes some time, but heating water in an electric-plastic kettle for example would encourage the release of the unwanted chemicals into your water. So, if you do plan to a plastic kettle look for a kettle that is labels BPA free.
As for the second point, after some time minerals from water will build up on the heating element of the electric kettle which may leave you with an unwanted taste in your cup of tea. However, there are ways of cleaning the kettle with vinegar to remove mineral buildup.
Microwaves
Microwaves are amazingly convenient and have changed the way we eat. It’s possible to have a hot meal with the push of a button. As amazing as microwaves are, they are not the best option for heating water to an appropriate temperature for steeping tea because of uneven heating. When water is heated in a microwave a temperature stratification will develop. The upper layer of water will be significantly warmer than the water in the bottom of the cup. Not the conditions you would want for brewing tea.
Water stratification cartoon (normal water to left, distilled water to right)
On a side note distilled water + a clean glass + heating in a microwave = explosion
Distilled water is pure water, no minerals or salts, just 100% water. Now when distilled water is heated (by a microwave) in a clean glass, the glass walls along with the cohesive properties of water will prevent the formation of bubbles which normally create movement and cool the water down. This now heated distilled water can actually remain in liquid phase for a few degrees beyond the expected boiling point of 212 F, essentially the distilled water becomes superheated. Uneven heating, temperature stratification, is also greater in this scenario (see above figure). Any disturbance to the glass and water will cause the water to escape - to explode. A simple touch, the simple action of going to reach and touch the glass, or dropping tea into the water will disrupt the cohesion of water molecules resulting in an outburst of heat, energy, and an explosion. Even the opening of the microwave door may be forceful enough to create a change in air pressure to trigger the explosion of water. I would also like to infer from the above scenario that using finely filtered water may also act similar to heating distilled water in a microwave. So please use caution if heating distilled water or finely filtered water in a microwave.
Pouring water
To properly infuse your tea, it is best to add the tea leaves to your cup or pot first and then pour the heated water over it. Many will claim that pouring directly onto the tea leaves will create a burned flavor. The tea does not burn really, but the moving water essentially pulls out more tea liquor from the leaves because of the flow of water over the leaves. So just to be cautious, it may be best to pour the hot water around the leaves.
Pouring tea from up high,
There is also a technique of showmanship prominently seen in the middle east and around Mediterranean where the hot tea pot is held high up in the air above the tea cup and then poured. This technique is continually exciting to see but also has a secondary purpose of cooling the hot water.
In conclusion I recommend heating cold water on the stove or by an electric kettle (BPA free is plastic). As for using a microwave to heat water I personally use this in the morning because I’m lazy but I make a quick Indian style milk tea, where there milk helps to balance out the bitterness of the tea. I also use the microwave to make a mate shot, where I’m trying to make a quick strong brew just for the energy. The microwave will probably never produce a perfect cup of tea like using a kettle could but everyone uses it at some point or another
(My lazy morning cup of Assam (tea bag) tea made in a 1100 watt microwave for 90 seconds)
I hope you enjoyed reading this blog post about how to boil water for tea. Leave your questions and comments below. A water blog post sequel is in the works where water quality, water temp, compound degradation and water activity will be discussed.
Appendix
Stove types
gas flame - thermal heating
metal coil - resistance heating
ceramic top - infrared radiation
Induction top - induction heating, requires ferromagnetic cookware.
Chemicals often added to treated/city water
Chlorine (Cl) - disinfect and kill microorganisms
Ferric Sulfate (FeSO4) - used on waste water to remove organic compounds and heavy metals
Fluoride (F) - to help reduce tooth decay
Lime (Ca(OH)2 )- is basic and is used to reduce ph levels, the other chemicals are acidic compared to lime
Polyphosphate (P)- to keep iron, manganese, phosphate in solution preventing build up in water pipes
Sodium Permanganate (NaMnO4) - prevents brown water- is an oxidizing agent that removes
Microwave safe glass test
Glassware with imperfections can also be a dangerous to use in a microwave. Try the following test found on the Michigan State University Extension page:
Microwave the empty container for one minute. It's unsafe for the microwave if it's warm; it's OK for reheating if it's lukewarm; and it's OK for actual cooking if it's cool.
