I'm not sure there's much real scientific research on preparation (at least when this was published in the 90s), especially as it can be quite subjective. There's a bit about factors affecting caffeine content on p.425:

> The quantity of caffeine that infuses into a tea brew is determined by infusion time and by leaf style. Longer infusion times lead to greater quantities of caffeine in a tea beverage. Smaller sized tea leaves give a more rapid and stronger infusion, whereas larger leaves and uncut leaves lead to weaker infusions. This results in more or less caffeine extraction, respectively. The caffeine content of a typical tea beverage will range from 20 to 70 mg per 170 ml of infusion, with a typical infusion being prepared from about 2 to 2.5 g of tea leaves. Coffee brews typically contain from 40 to 155 mg caffeine per 170 ml beverage. There has been little research done on the pharmacology of tea-beverage caffeine. One study suggests a dose of caffeine from tea has a different physiological effect than a pure dose of caffeine (Das et al., 1965). This has been attributed to the amino acid theanine, which is unique to tea. However, there are no well-designed clinical studies to support this position. The consensus among scientists today is that caffeine from all beverage sources has a similar physiological effect. The actual content of caffeine depends on many factors, particularly the method of brewing. A brew prepared by the Chinese "gong-fu" style is likely to have a different caffeine impact compared with the Western style of loose tea or to that from a tea bag (Hicks et al., 1996). Some reports have suggested that green tea contains significantly less caffeine than black tea. This may be influenced by the clone of leaf used to produce the tea or by the impact of different brewing techniques. No significant differences have been found when brewing green and black teas under similar conditions (Hicks et al., 1996), discrediting the theory that withering and fermentation have a significant impact on caffeine content (Sanderson, 1972).

Well, depending on what you drink there are articles about that: https://news.ycombinator.com/item?id=35658412

The BBC has come up with an excellent short documentary on how to perform proper tea preparation [1].

Essentially the hot water need to be boiling hot (100 degree celcius) and leave it brewing for a minimum 4 minutes after pouring into a cup of tea.

From personal experiences, if you want to make good chai masala (or spicy milk tea) you need to keep it in boiling water for considerable amount of time (like cooking on stove), with the ingredient of tea (generous amount), equivalent amount of evaporated and sweetened condensed milk (like half can of milk for medium pot), together with combination of your preferred different spices for examples cinnamon (Sri Lanka cinnamon not the fake ones), jeera, clove, star anise, etc. Since the condensed milk is already sweetened, no need to put sugar, but you can add pure honey for extra wonderful aftertaste.

In UAE, karak chai is their national drink that are sold in most of the restaurants and eateries. Fun facts, and heaven knows for whatever reason the default tea brand being used there is always Lipton.

[1] How you've been making tea WRONG your entire life - BBC:

https://youtu.be/Fhuc6qOGNPc

It depends on the tea you’re brewing, what you want to make with it, and your personal taste. How could there possibly be an objective answer?

6 heaping teaspoons of tea per quart of water seems like a lot of tea.

Lot's of red flags in his way of tea making, but what can you expect from a British born in India on foods or drinks.

> "First of all, one should use Indian or Ceylonese tea. China tea has virtues which are not to be despised nowadays—it is economical, and one can drink it without milk—but there is not much stimulation in it. One does not feel wiser, braver or more optimistic after drinking it. Anyone who has used that comforting phrase ‘a nice cup of tea’ invariably means Indian tea."

These are some of the worst tea-making tip I've ever seen. I get that taste is subjective and all, but come on... This is like saying:

"Al Pastor street taco in Mexico has its virtues - it is economical, and one can eat it without salsa - but there is not much stimulation in it. One does not feel wiser, braver or more optimistic after eating it. Anyone who has used that comforting phrase 'a great taco' invariably means Taco Bells"

CTC tea [1] is inferior in quality. They are mass-produced, brews quick, and tastes way too strong (hence the milk). Tea was invented in China and tea culture goes back thousands of years. India and Sri Lanka only started producing tea in the mid 1800s. Robert Fortune literally dressed up as a Chinese merchant, snuck into some rural village in Fujian, and smuggled some teas back so the British East India Company can cultivate it in and around India.

[1] https://en.wikipedia.org/wiki/Crush,_tear,_curl

Salted black tea with butter is delicious (https://simplytibetan.com/2010/12/07/bho-ja/)

When I switched to black coffee I read that putting a tiny bit of salt in cuts the bitterness. It works and the amount of salt needed is so small that you don't taste it, less than a pinch.