Friday, April 13, 2007

Don't use a filter

In his second article on gongfu cha technique, Teaparker reminds us NOT to use a metal filter between the teapot and the cups. Metal will change the fragrance and the taste of tea.

The residues will give you additional information if you want to judge a tea for its quality. And if you just want to enjoy your tea, just think of them as charming tiny parts of beautiful, natural tea leaves.


Vladimir Lukiyanov said...

I too find that a few bits of tea dust floating in a cup of swirling hot tea are often quite beautiful in themselves.

Most of these metal filters also tend to be quite ugly...



venant tout droit de provence , said...

sur les conseils de Jérôme D j'ai arreté d en utiliser .Je l'aovoue j'etais un fervent utilisateur de ces filtre. Mias je me suis soigné , et depuis ca va mieux .
sinon il faut avouer ques les petits morceaux qui se troucent au fond apportent un plus au thé , plus de vie ;-)

Philippe said...

Oui mais alors ta théière en argent qui est une sorte de métal on va dire, n'influence-t-elle pas elle aussi sur le rendu des infusions ? D'ailleurs pour être honnête, c'est la raison principale de ma méfiance à l'égard de ta théière (outre l'aspect esthétique bien-sûr; on aime ou on n'aime pas mais là n'est pas la question...).

Anonymous said...

Bonjour à tous,

La question de Philippe m'intrigue. N'y a-t-il pas de la terre cuite à l'intérieur du revêtement en argent ?

Au niveau du restaurant, il m'est parfois difficile d'imposer les feuilles aux convives. Cela dérange certaines personnes.
J'avais vu dans le catalogue pro du palais des thés des petites passoires en bambou.

Qu'en penses-tu ?

Bonne journée,


TeaMasters said...

Non, il n'y a pas de revêtement en terre cuite à l'intérieur. C'est de l'argent massif.

l'argent a des propriétés chimiques neutres. Il n'influe pas sur chimiquement sur le thé. On ne peut pas en dire autant du fer et de l'inox. On peut en faire l'expérience avec les couverts de table. Boire une soupe avec une cuillière en fer ou en argent, c'est très différent.
L'argenterie existe justement car elle elle n'influe pas sur les aliments en général.
Et si cela ne te convaint pas, je peux toujours rappeler Lu Yu à la rescousse. Pour lui, l'argent et l'or sont les meilleurs matériaux pour faire du thé!

Anne encore,
Le bambou aussi donne une odeur... de bambou, et puis il y a un risque supplémentaire de moisissure si on s'en sert très souvent.

venant tout droit de provence , said...

il me semble philippe que j'avais posé la même question que toi sur un post different car j'avais eu la même reflexion ;-)

Unknown said...

Everybody claims that metal is bad for tea, but I have not seen any scientific explanation why stainless steel, which is supposed to be reasonably inert, should change the taste of the tea. Can somebody enlighten me? Feel free to use even university-level chemistry/physics, I really would like to know the answer.

TeaMasters said...


Sorry for not providing a more scientific explanation. You mention stainless steel is 'reasonably' inert, but not completely. The best way is to experiment. If you lick a stainless steel fork or knife, or if you drink from a stainless steel glass, you will feel a (unpleasant) metallic taste that you don't feel with ceramic, glass or silver. I have both steel and silver forks and I can tell you I dislike using the steel ones.

Also, except for keeping water warm, nobody uses steel to make wine, water, beer... glasses, despite the fact that it would solve the problem of broken glasses.

MarshalN said...

Funny you mention this, because in this picture:

I spot what looks like plastic water heaters to me. When I first saw that picture I was wondering why these things were used. In my experience, plastic water heaters of that sort (with what must be a steel heating element, by the way) is far more damaging to the taste of tea than any momentary contact with a stainless steel mesh filter will ever do.

So using those are ok, and using a steel filter is not? Or perhaps the water heaters are steel? Even if they're steel, the same point still stands.

Mind you, I never use a filter, I'm just asking because things aren't adding up -- why care about a filter when your water is being heated in a plastic container with a steel heating surface? Unless you tell me they are heating the water in those things for something other than tea drinking at a tea gathering.

Veronique said...

I think Stéphane is always trying to communicate with us what the 'ideal' conditions of tea making are but when other people are involved some things might not be perfect.
I don't think Stéphane could have started lecturing these ladies about their 'convenient' method of boiling the water even if this was to affect the tea negatively.
I work in 23 year old traditional chinese tea shop and we have to let people taste teas and we do it 'gong fu cha' style so it takes time. We use those automatic metal ketles... This is not ideal but convenient. I personally can't stand residue in my tea so I have to put up with the filter. Thank you Stéphane to make us dream about the ideal way of making tea. This is why chinese tea is still today my number one passion.

Anonymous said...

MarshallM, are you working for the secret service?
Good point though, but did you ever think that it being a tea class they need to warm up and wash the teapots + utensils for each tea, say 3 teas per session, that's at least 6 boils per person, and is there not a tetsubin on the table too?

~ Phyll said...

I don't use any filter unless the tea has too much dust, then I'd use the fabric filter (that dried gourd thingy).

However, in response to your (Stephane) comment that "...nobody uses steel to make wine,...."

In the wineries, white wines are fermented in huge stainless steel tanks these days...even the top chateaux and domaines employ them. These are very serious people we are talking about, and if the SS affects the taste of their wine even minutely, I am positive they would not have used them.

Then again, maybe tea reacts differently with SS? Hard to imagine...

TeaMasters said...


You make a good point that these water heaters were not ideal. We even felt that some brews were affected because the water had boiled too quickly and strong. So, I agree with you that we should have used different heaters, especially for the delicate orchid oolong we drank that day.

Teaparker may want to think about it again in the future. However, we had 4 people brewing tea at the same time (with 2 heaters) and this was, as Veronique pointed, done for more convenience at this location. It's a balance between ideal tea and crossing Taipei by MRT packed like a mule!

Anyway, your keen eyes will have noticed before that Teaparker is not using such water heater at his tea place:

and that myself will bring my tetsubin (and gas heater) outdoors, if I can park close by:

However, there is a difference between water touching stainless steel and tea touching stainless steel. Tea has so many components, and the most fragile ones will react with steel.


My quote was actually 'nobody uses steel to make wine (...) glasses'. We still prefer cristal glasses for wine. You raise a good point, though, but I think the wineries using steel during the big process and part of the storage of wine (later we store it in glass bottles!) can't be compared the small act of gongfu cha. And at that stage, it is OK for the wine to change. Actually, using oak tanks it used to change wine even more. Some will put pieces of oak in the steel tanks to give the wine oak taste nonetheless...

MarshalN said...

I understand there are practical concerns -- which is why I didn't mention anything in the original post because I know they need to heat up big amounts of water, and using a fire/coal/whatever burner would take too long. I think they could've used a few heating plates, since it seems as though at least some of the members of this group use metal water servers. In fact, come to think of it -- why not buy a few cheap heating plates and just heat water up that way?

Given the way Teaparker wrote about it in such conclusive terms, I was a little surprised, I guess, that he was ok with using plastic water boilers, which I find to be the worst kind of boilers out there.

MarshalN said...

Come to think of it

A blind taste test of the same tea, one having gone through the filter, the other not, would be able to reveal whether there is any difference... and whether that difference is at all noticeable to the human tongue. Blind test would be the key though, as we all know our other sensory perceptions will interfere with the way we think something taste.

TeaMasters said...

I will suggest we improve that point for the next tea party. I have a light gas heater I could bring if others bring their tetsubins again.

Thanks to you and all others for the open and constructive comments.

TeaMasters said...


Your last comment came too quickly. I was writing my own comment in the meantime.

The blind test is a good suggestion. I won't be able to do it soon, though, ...because I lack a filter.
It really needs to be blind, because the sight of residue will tell you which cup had the filter.

To make the same tea, it should be poured out of the teapot by going often to cup A and B (with and without filter) to avoid that one cup gets the beginning of the brew and the other one the end, which would taste different.

Also, best is too choose a more delicate high quality tea brewed rather light (green tea or gao shan cha) without astringency to make this test. How long the filters stays in contact with the tea may also play a role.

Still, it may be that most or all of us won't notice the change. (I'm hedging my bets here!!!) But we would probably see a difference if we brewed the tea in a stainless teapot instead of in a gaiwan or a clay teapot. I see no expert recommending brewing tea in steel pots! That means that, to some degree, tea and steel don't match. So, even if the change is very small, it is not a proper thing to do. To take a wine analogy, a French joke is that red wine and coca-cola shouldn't be mixed together. So, even if you only add a tiny drop of coca-cola in the wine glass and the expert/drinker doesn't taste it doesn't mean it's OK to add a tiny drop coca-cola to your Ch. Margaux. You will shudder at the thought and wonder about the risk of putting too much in it.

Ido said...

Re: cups (have not yet tried blind testing with filters).

I think Veronique said it all "I think Stéphane is always trying to communicate with us what the 'ideal' conditions of tea making are but when other people are involved some things might not be perfect".
Assuming of course there is an acctual difference.

Assuming there is a difference it is perhaps because of the reasons Stephane mentioned:
"You mention stainless steel is 'reasonably' inert, but not completely."
"However, there is a difference between water touching stainless steel and tea touching stainless steel. Tea has so many components, and the most fragile ones will react with steel."

Having made several blind tests in the past where I used stainless steel cups in comparison to other types and quality. I could tell there is a difference (I recommend you too try. Nothing like finding out your self). Most of the times stainless steel tasted much worse then quality ceramics cups.
Try using paper cups (or for that matter paper filter?)... .

If after experimenting you don't taste a difference you are GIFTED with the ability to buy cheaper tea, wine, cheese and any other thing that goes through your mouth (it might take some time to get used to the small nuances).
All that is left to do is to make sure that nothing tasteless comes out of your mouth.

~ Phyll said...

Stephane, I obviously only read what I wanted to read, sorry. Thank you to google, apparently metal wine glasses are being China! (I didn't know!)

My point, though, is not completely moot. The concept still holds true in winemaking: oak imparts taste and tannins, while stainless steel is neutral. It was Monsieur Emile Peynaud who pushed for the use of SS vats. Imho, metal wine goblets are rarely used these days as a matter of aesthetics and of today's custom but not for taste improvement (crystal is perfect for checking color and the wine "feels" better drunk from a very thin glass). Anyways, again too much vinotalk by me.

I also was taught that metal shouldn't touch tea, and I'm still not sure why silver should be excepted. Whatever I was taught with, however, I have never verified its truth or scientific sort of become a mindset.

You said: "...because I lack a filter. It really needs to be blind, because the sight of residue will tell you which cup had the filter."

Since the central issue is about *metal* filter, you can still use a non-metal filter to compare the tea against. This will be more convenient as people don't have to drink with closed eyes...both cups will be about equally clean.

TeaMasters said...

Thanks Ido for sharing your experience that tea from a stainless steel cups tastes bad compared to a ceramic cup.


I love (your) wine talk! It doesn't bother me at all. I also find many parallels between wine and tea. But maybe there are a few differences, too (alcool content, wine's stronger taste...) that make that its reaction to (what I think is high grade) stainless steel for big wine volumes less comparable to the reaction cheap steel filter have on small amounts of fine tea.

The cups you show resemble the wine cups from the middle ages in Europe! But I think at that time it was made by tin (étain).

You're one of few to have experienced the silver teapot. Experience is really key to reject wrong theories. Then it's also a kind of etiquette or a kind of respect. Another wine analogy: you don't shake your wine bottles in your cellar each time you go and pick a bottle. Maybe you don't feel a difference in taste (after all, the bottles will get shaken several times on their way between the winery and your home), but it's just not a thing to do, whatever the difference in taste.

MarshalN said...

Ido -- did you drink from the stainless steel cups vs. the ceramic ones?

~ Phyll said...

(nothing to do with metal filter...vinotalk again)

Funny you should mention about shaking bottles in the cellar (no one should do that).

Have I told you that I went to a wine tasting where Olivier Humbrecht, your fellow Alsatian who is the winemaker at Domaine Zind-Humbrecht, was the guest of honor? He told everyone there that if any of us should drink his wine (he only makes white wines) less than 3 years from release, we should decant it first and let it sit for 1/2 hour or more. The best way to decant his delicate wines: put the bottle upside down and shake it up-and-down to let the wine gush out like crazy. No need for delicacy like you would when you decant a red wine.

Maybe his wines should be shaken in the cellars from time to time... :)

Ido said...

MarshalN - Yes.
Soon I will post an article of my experiences with a silver "Kiddush" cup (only 925).

Having said that all the cups I tested/tasted from are more or less different in size and shape. I believe this too contributed to the results. Of course there are all the other little nuances, but I don't take it all too serious - although that is the point-in a way!

It was as scientific as I could do it at the time. One can always(!) argue about the conditions and we should! I am not yet able to make for better testing conditions. But from my experience it is definite -so far.

For all it matters, I do buy cheap! "Kiddush-wine" for my over paid Kiddush cup. And I do say sadly way too many tasteless things.

Unknown said...

As for the tests suggested, only one makes sense: brew the tea, pour into a pitcher (to have an even infusion) and then into two cups using a) stainless b) nylon strainer. Then blind test the tea in those two cups. I should do that at some point :) Brewing/drinking from different kind of vessels intoduces too many differences.
As for metal cups - well they are not used since they 1) have high termal conductivity, so it is not a good idea to drink hot beverages from them 2) aesthetically glass is better, since you can really appreciate the look of your drink.
Being from a wine-growing area I have to agree with phyll - if stainless is ok for wine, why not for tea? Actually, that's also one reason why I asked.
So does anybody have a scientific explanation (e.g. reaction of tea with chromium/nickel in stanless) and can back this up with a source citation?

Anonymous said...

What about water boiling in a cast iron kettle? Does this affect the taste also?

Then about comparing stainless steel cups and ceramic cups, I think the comparison is twisted because of the way stainless steel itself feels in the mouth compared to ceramic (thinner, colder...)

But then the solution would be to use a filter made of silver threads :)

TeaMasters said...


Boiling water in an iron kettle affects taste (positively, most of the time, if you don't let the water sit for hours).

I did some googling about stainless steel and found some contradictory info. On the one hand, they say it doesn't affect flavor, but they also say that if you keep liquids for a long time in a stainless steel recipient, then it will absorb some Cr (Chromium).
They say it here:
"When food in stores in steel tanks or cans chromium concentrations may rise. "

and here:
"Because oxygen is necessary for the reaction, liquids and other foodstuffs stored for a prolonged time in stainless can prevent oxygen contact and thus promote corrosion...

Chromium is also beneficial in small quantities, and you would have to cook four complete meals in the same stainless steel pots every day to come anywhere close to reaching any adverse affects from chromium intake...

Do not store food or liquids in stainless steel cookware after cooking."

It reminds me that I noticed some corrosion on some tea filters that are used often... They don't seem to be made of very high quality steel. (The second link shows there is a big variety of quality in stainless steel. I guess wineries use a high quality steel that takes this problem into consideration).

I tried a non-blind experiment today (with tea in contact with stainless steel), but I wasn't very concentrated. The difference, if any, seems very small indeed. However, I remember that tea I keep in a stainless steel cup for hours turns out worse than one that is in a ceramic cup.

This is in line with what I found on the net: not to keep food in stainless pots too long. The longer, the more obvious the effect. That's the coca cola addition to wine analogy I made earlier. Using a filter for a short period of time may not change the taste significantly, but because it would over time, it is tasteless (!) to do so.

Anonymous said...

Salut Stéphane, Je me suis lancé dans le monde du Blogg.. Je novice..

Anonymous said...


La seule chose que je connaisse aiu niveau des ions argent (en dehors de leur utilisation en photographie), c'est que ceux-ci ont des propriétés bactéricides. Cela dit, je ne crois pas que cela ait un quelconque rapport avec le fait d'utiliser une théière en argent massif.