Tea and the Taste of Temperature

How much water to add to your tea to bring down the temperature?

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It is frequently recommended, for example, that white and green teas be steeped significantly below the boiling point of water. According to Wikipedia, black tea is steeped at below the desired ~210 F at high altitudes. Now, I mostly just put lots of leaves into water straight out of the kettle, and let it steep until I finish drinking the entire cup. But what if I wanted to try something different?

Without a thermometer or a fancy tea kettle that maintains a set temperature, it is still easy to lower the temperature with cooler water. So here are the steps.

  • Guess the temperature of the water you're using.
    • Room temperature: Do you leave it in a Brita? Do you have a lot of indoor pipes exposed to the ambient room temperature? My preferred room temperature is 70 F.
    • As cold as tap water gets: Look at [this] chart. Cold tap water is probably a little warmer (or colder, depending on season and geography) than the ground water resevoir (assuming you get your water from wells). If you've ever had a tour in a cave, you know that the temperature below ground doesn't vary very much throughout the year. In drier climates, you can expect more seasonal temperature variation (see article). We'll find out it doesn't matter too much. In Reno, NV, the ground water temperature is 52 F.
    • Refrigerator water: is probably about 36 F. ( source)
    • Ice cubes: 0 - 32 F, depending on freezer temperature.
  • Get your target tea temperature. For example, wikipedia suggests: ... Pick a temperature in the middle of the range, it won't matter too much
  • Find out your elevation: I am at 5000 ft, and the boiling point decreases from 212 by about 2 F for each 1000 ft you are above sea level. So my water boils at approximately 202 F.
  • Are you sure you're adding water? If you're adding mercury or something else, we have to recalculate the substance density and use a less simplified formula.
  • Compute.

I lied when I said I didn't have a thermometer: I was just too lazy to walk over and get it. Instead of measuring the water temperatures, I left the kitchen for pencil and paper, pulled out my phone, and did some calculations. But I gave in and took some measurements because I wasn't sure if using a tea kettle would raise the boiling temperature of the water. The whistling is caused due to a slight(?) pressure build up, which raises the boiling point.
Tea kettle data

Wikipedia currently claims that

"Many of the active substances in black tea do not develop at temperatures lower than 90 °C (194 °F). . . . The most common fault when making black tea is to use water at too low a temperature. Since boiling point drops with increasing altitude, it is difficult to brew black tea properly in mountainous areas."

In order for the boiling point to be 194 °F or below, you would have to be at roughly 9,000 ft or higher. Yes, there are plenty of cities at 9000 ft or higher in the United States and everywhere else. And if you are an avid mountain climber who loves tea, it will probably never be hot enough. But most people don't live at those elevations.

FDA source: http://www.fda.gov/Food/ResourcesForYou/Consumers/ucm253954.htm
                < 40 F
                35 - 38 (comfortable margins from 32 and 40)
                position in refrigerator, zoned fridges, door warmer (59??)
                0 F

Ground Temperature:

Boiling point T: