Microwaved, tepid, rolling boiling? Water for tea!

Look after the water and the tea will look after itself.

This sounds simple and is. But many tea drinkers aren’t aware of just how critical water is. The very same tea can taste terrific, disappointing or even awful because of easy to overlook and easy to repair small variations in water quality, brewing temperature and steeping time.

Here are four rules:

1. Use water that is neutral in terms of acid and alkaline levels. Most tap water is slightly acidic and soft. Avoid hard water with any taste of minerals. Filtered is preferable. Bottled is unreliable.  
2. Heat the water to the temperature best suited to the leaf: high for blacks, lower for greens. The range is from 170-212 degrees. Greens brewed at boiling point will be nastily bitter and blacks tepidly heated at the lower end flat and lacking flavor.
3. Avoid the temptation to steep the tea for more than the few and specific minutes that the tea type requires. Longer does not mean stronger, only more bitter. The median time is just three minutes, with black teas up to five and Japanese green teas as short as 1.5 minutes.
4. Do not touch the microwave. Treat the oven as a tomb where teas go only to die. The physics of “boiling” water in microwaves are akin to bomb-making.

One of the most common complaints about tea is that it is too bitter. This is almost always because of the water, not the tea – if it’s leaf grade and not a bag of dust, twigs, filler extras and additive flavorings. Water can’t improve a bad tea. But water can help the complex synchronization of the dynamic chemical interactions of the leaf’s polythenols and tannins.

Polythenols are a store of time-release compounds that very subtly build the texture, astringency and “body” of the tea taste. They break down into catechins plus theaflavins and thearubigins. Very roughly, catechins contribute to the lightness and sweetness of the tea and the others to its fullness and boldness. Tannins give the tea its astringency.

The purpose of the tea temperature and time combination is to regulate the flow and balance of all the compounds. For instance, when you brew green tea at too high a temperature for too long, the tannins overwhelm the entire drink. You commit negligent tea-icide.

This is chemistry in action. The water will affect the tea, rather than the other way round. “Will” means determinedly, remorselessly and precisely. Not “kinda.” With experience, you can modulate the variables a little to suit your preferences, but the parameters are pretty fixed.

Choosing the water

Always find good water. “Good” here means as close to being pure as makes sense. For some tea experts, the available water is never good enough. They want the equivalent of a pristine mountain stream. There is no need to go to such an extreme for almost all the teas you are likely to drink on a daily basis, even if it were practical.  But rare ones, especially the most subtle whites and greens, demand meticulous handling and a very discriminating palate. They deserve water that brings out the best of both tea and taster.

The more general aim in choosing water is simply to ensure that you taste what the tea producer intended. The priority is to avoid hard water that is high in minerals; that’s generally easy to spot from the taste or by its leaving a light film across the surface. Soft water makes for flat-tasting tea, so avoid distilled water with its low minerals. You need a neutral pH acidity level of around 7.

Water from the faucet is adequate in many regions, though it is often affected by minerals, old pipes, chlorine and occasional nasties. The practical home choice is simply to add a water filter to your faucet, such as the Brita brand. Using bottled water is generally less satisfactory; it’s expensive and in many instances not good quality; the market is unregulated and notoriously prone to shady practices. That said, the large bottles of spring water that are part of the office coffee and teabag scenery are pretty reliable. In the many tests of teas and water, filtered water is consistently the most highly rated.

One expert offers a simple general rule. He found no consistent differences in ratings for the same tea brewed with tap, filtered, gourmet bottled and bottled spring water. He comments that if you wouldn’t use your tap water as a regular drink, then don’t make tea with it.

Setting the heat and time

Here is a simple summary table of brewing rules for different types of tea. Most people don’t have access to a portable thermometer, so it includes guidelines on how long to leave the water after it has boiled to cool to the required temperature. The best tea makers have a built in time/temp setting.

Don’t play around with green teas; they are carefully cultivated and nurtured to release their flavor at 170-185° and artfully tailored to punish the taste buds of those who trespass outside the heat limits. Japanese greens are the most finicky here; a good fukamushi (deep-steamed) sencha should be made at 150º/1.5 minutes versus 160º/1.5 for a light-steamed asamushi. At 170º/2.5 minutes both these teas are transformed from exquisite to truly execrable.Adjust the specifics to meet your personal preferences but only within very narrow ranges. The general instructions for black teas, for example, recommend using boiling water at 212°F (100°C). This can be a little harsh so try 205° when you’re using a Darjeeling or subtle China Keemum; around half a minute off the boil.

In general, a useful subrule is when you are not satisfied with a tea, don’t increase the time or temperature. If the tea is too weak, add more leaf in your next brewing. With tea, less is generally more. It’s ironic that in our age where, in Carrie Fisher’s piquant epigram, the trouble with instant gratification is that it’s just  not fast enough, so many tea drinkers delay getting their gratification by brewing it for as long as ten minutes. When in doubt, choose 3 minutes.

Tea bags throw off all calculations. Their ingredients are generally chosen to handle a wide range of water temperatures and to provide a fast burst of flavor that can get through the porous barrier of the bag itself. A quick scan of online recommendations for tea bags shows no consensus: 4-8 minutes is typical and 6-8 occasional, along with 1-2. Again, for those who do drink tea bags, the suggestion is less not more: shorter times.  

And no microwave.

Microwaving tea water: Q: is it safe? A: “not really”

The wide literature, both popular and scientific, on making tea in a microwave is very entertaining. The “not really” answer to the safety question is an instance. That amounts to: it’s generally OK, but you have no control over the temperature, you can’t tell if the water is going to hiss, bang or explode when you add a bag, there is a little toxic gas created when you nuke polystyrene though “it won’t kill you but I wouldn’t do it on a regular basis”, “plastic [cups] don’t play nice in the microwave”, and, a personal favorite: “what’s that white foam I get on my tea?”

Microwaving doesn’t “boil” water. It’s rather like Stars Wars Stormtroopers randomly zapping 4 inch jolts that create “nucleation points.” A kettle uniformly builds heat from the bottom up and it cycles down to keep an even and smooth flow. Microwaving leaves some areas cold and others invisibly higher than the 212º boiling point. Or not. As you can guess, if the Stormtroopers, whose aim is somewhat unfocused, hit that little metal staple on the tea bag…

All this creates some very complicated reactions that include superheating (turns your cup into a dangerous steam grenade), loss of oxygen (blands the tea down to insipid) and accentuation of the taste of impurities from the water and even the cup material. (How bitter can tea get? Boil it for just a few more minutes and you’ll find out.)

There’s some striking evidence, too, that microwaving water leeches out its nutrients. It’s shown by a simple experiment that has been repeated many times. Two identical seedling plants in identical soil are treated over 7-9 days, one with water that has been microwaved and the other with purified water that was boiled in a kettle. From Day 1 on, the results are consistent. Microwaved water starves the plant.

If you enjoy tea as more than a hydrator and morning energizer, it really is worth following the four rules. Obviously, that’s trickier on the road or office versus at home. The ideal is a filter on your faucet, a cheap kettle, a pot or infuser to brew tea in, your wrist watch for timing, and a good ceramic or glass cup. You can carry the tea with you – and it doesn’t have to be in a bag. All you need is a small basket infuser and some small tight container.

In the office, your compromise may need to be the same. Access to the standard large flagon of spring water in the coffee room and a way of heating the water. That may require you store a small plastic kettle/heater somewhere in the office.

It’s worth it. The corollary of look after the water, and the tea will look after itself is that if you don’t look after the water, the tea can’t deliver the taste and flavor.

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