Many essential aspects factor into a good cup of tea. Arguably the most important factor is water. Tea is mainly water; it's at least 95% of the bowl. So what is it about water that makes a difference? The two most significant categories to discuss when talking about water for tea are temperature and quality. We're going to break down why temperature matters, and what it does to your drink.
Different teas require different brewing temperatures to maximize the best qualities of that particular leaf. Usually, on loose leaf packaging, you'll find instructions. How did we come up with those numbers? So if I don't have a temperature telling kettle, how do I know what temperature to brew?
No Thermometer? No Problem.
To get an idea of water temperature without a thermometer or digital kettle, you can train yourself to understand it by touch. Many times we can get a feeling for how hot water is by touching the container it's in if it's a thin-walled vessel or putting our hands above the water to feel steam. We do not recommend trying to tell the temperature of your water directly from the kettle on the stove. Transfer it to a hot water safe pitcher or bowl.
Hot water generates a chemical reaction to the tea leaves. The compounds inside the leaf dissolve when in contact with water, letting the taste and aroma to roll out. Different styles of teas have different ratios of these compounds, which each have different temperatures required to dissolve and release. For example, black tea is high in polyphenols, which need high heat for release. Other teas, like Japanese Gyokuro, require shallow brewing temperatures; otherwise, you run into destroying the delicate organoleptic properties and aroma of the drink. The low temperatures also allow the umami texture to take hold in a Gyokuro tea. The heat highlights this feature of the tea, rather than turn it into astringency or bitterness when brewed too hot.
A rolling boil will dissolve much of the oxygen in the water, which is a factor for good quality tea. You don't want to lose that oxygen, so full rolling boiling water is not ideal (unless directed to on tea package). In addition to that, boiling water multiple times dissolves the oxygen even further, flattening the taste of your water and in turn, your tea.
Here are some general rules based on tea type, but reading individual packaging is still best! Green and white teas are the most delicate, requiring temperatures way below boiling. Oolongs are a bit harder, using higher (but not boiling) temperatures and blacks, herbals and pu'ers are the hardest, that can handle and benefit from high heat. We like the recommend when in doubt, use slightly cooler temperatures.
We hope this helps increase your brewing skills and knowledge! Let us know in the comments below if you have more questions or information on this topic.