; Cwyn's Death By Tea: How to Season and Clean Clay Kettle Boilers ;

Wednesday, October 11, 2017

How to Season and Clean Clay Kettle Boilers

I don’t know whether a post on clay water boilers is of interest to anyone, but I might as well post what I do with my clay boilers. 

Clay teapots and boilers can enhance puerh teas, or at least diminish storage effects on older teas. Clay is also mitigating our water as well as enhancing flavors in tea. Any boiler or tea kettle may perfectly suffice for most people, and I believe that no special equipment is necessary for boiling water. Yet you may wish to consider a clay boiler down the road. These boilers are quite nice to have for brewing tea out of doors in areas with no electricity, such as on a camping trip. Like clay teapots, a clay water boiler softens water and enhances flavors within the tea. Clay boilers also allow one to use lovely porcelain tea ware while still enjoying the enhancements clay brings to tea sessions.

A clay kettle may be used on a burner or kitchen stove or on a charcoal warmer designed especially for clay kettle boiling. The standard advice with a clay kettle is to decide which sort of burner you want to use, and stick with one burner type only. I personally do not believe this is the case, as long as you use the lowest possible heat setting on whatever type of burner you choose. The key is heating the clay slowly.

Some tea drinkers prefer to boil their water in a faster electric kettle, use some to warm their clay kettle first, dump it and then add boiling water. Then the clay kettle stays over a low heat burner to remain warm during the tea session. I use this method, but also I have started with cooler water. As long as the kettle is not starting out ice cold and heated too quickly, there is no danger of cracking the kettle. Keep in mind if you start out using cool water, your clay boiler will need more time to heat up using a very low heat flame or burner.

I own three clay kettles because well, I am a pig first of all. Nobody needs three clay boilers. I am hopelessly addicted to tea ware. I could argue that I like testing various clays and justify my purchases for the “sake of the blog.” Hahaha. Anyway I own a Lin’s Ceramics Purion kettle, a Chaozhou (or Chaoshan area) red clay boiler, and an art ware kettle made of high fired clay by Petr Novak, a well-known Czech artist.

You can find a Chaozhou red clay teapot from Chawangshop.com, they have a nice selection of these kettles and also the proper stoves for sale. Shipping cost is a factor. A kettle or stove must be shipped separately from anything else in your order, adding approximately $20-25 to the cost. Even with the extra shipping, you can get a nice kettle and stove set-up for under $100. But you can also find clay kettles sold from many other sources to compare.

How to Season Unglazed Clay Boilers

Chawangshop recommends their boilers soak in water for 24 hours prior to use. I asked about using a food starch seasoning as this is what I normally use. The traditional starch is rice starch. Chawangshop replied that this method is not necessary for their clay Chaozhou. You can find their instructions on the listings.

Clay Chaozhou from chawangshop.com
For me, I need to consider that while my water is not terribly full of minerals and my kettles do not build up much scale, I would rather prevent this scale from building up. Once the scale forms it is difficult to remove without using anything other than water. A simple food starch seasoning will slow down any scale formation. A starch seasoning needs only to be done one time.

Corn Starch or Rice Starch

These starches are good for very fine particle clays. Start with a dry pot and fill with room temperature water, add a heaping spoon of starch to the pot and stir well. Heat the boiler to boiling over the lowest possible heat temperature.

To use rice, mash cook rice on a plate and then add it to the boiler with water and stir well.

Adding corn starch to water.
I used a tea brush to clean off the mess.
Tea boat by Mirka Randova.
Boil for 1-2 minutes, remove from heat.

Pour off the water as soon as it is cool enough to pour, minding your hands.  Remove any rice if you used rice.

Do not rinse the pot. When the water is poured off while very hot, the remaining water will evaporate quickly leaving behind a film of starch.

Allow the kettle to dry for 24 hours without the lid.

Potato Starch

Cooked potato or potato flakes are a nice alternative to corn, and the cooked potato will fill a more coarse type of clay kettle such as my Novak. Potato works very well with composite clay kettles.

Local tater.
Mash a small cooked potato in a bowl.

Mashed potato with peels removed.
Add the potato to your clay boiler and top with warm water. Stir up the potato.

Add hot water to potato.
Clay kettle by Petr Novak.

Boil the kettle over the lowest possible flame slowly. Allow to boil for 5-10 minutes, stirring occasionally until the potato is mostly dissolved. 

Stir with wooden spoon or bamboo skewer.
Do not rinse, any remaining hot water will evaporate very quickly.

Use a tea pot brush if necessary to remove any excess starch left on the bottom or around the top.

Allow the kettle to dry without the lid for at least 24 hours.

Photo of the lid just after the starch procedure.
A bit tough to see a film left from the starch,
which has mostly soaked into the clay and will dry.
Using the Clay Boiler

You may want to toss the first 1-2 boils to remove any excess starch or use them to water plants.

Do not use ice cold water; allow water to reach room temperature if you are using bottled water. Warm water from a thermos is also okay. The idea is not to shock the clay.

Bring to a boil over the lowest possible temperature on your stove or burner.

Use all the water, or pour off any hot water when your tea session is finished. Do not let water sit in the pot after use. Allow to dry for a full day with the lid off.

Cleaning Exterior Stains from Clay Boilers

Stains add charm to a well-loved clay boiler, but sometimes people want to remove them. Cleaning clay is like cleaning vintage or antique items in that we want to use the least intrusive, least harsh methods first. So, try water with a tooth brush first.

Next, use a slurry of baking soda and water with a toothbrush, and gently brush stains. Wait about 10 minutes, and then wipe off excess. Pour hot water over the entire pot to remove the soda.

My Lin's Ceramics kettle has a few stains.
Normally I would not remove these, but
this is for demonstration.
The next step if you are not yet happy is to use whitening toothpaste. I like Gleem, it is an older and gentle whitening toothpaste that works very well on vintage plastics, glass and porcelain. Gleem will also remove yellowing from your car headlights. I don’t use Gleem on my teeth, but I always have some in the house for cleaning.

Baking soda and water slurry.
Wet-brush the stain gently with Gleem, can also be used on top of the baking soda if you wish. Pour hot water over the entire kettle to remove the toothpaste or baking soda.

Gently brush on baking soda slurry or wet toothpaste.
If you are still not satisfied, you can repeat any of the above or proceed to a dry sandpaper of 300-400 grit. This is the harshest method, so test the sandpaper on the bottom of the boiler first to see how much it affects the color of the clay. Sandpaper will also remove patina, the last thing you want is a more prominent stain. Sanding should be a last resort. At the same time, if you burnt your boiler to a black char on a tea stove then you may wish to completely sand off the char, although there is nothing wrong with leaving it charred.

Stain has lightened somewhat to blend into the pot.
I could remove more of it, but choose not to.
I would not recommend cleaning the interior of the boiler. As long as hot water is poured off and the kettle is allowed to dry after use, then further cleaning is not necessary. If you happen to get dirt or scale inside, boil water in the kettle and pour off.  Wipe out any remaining particles.

I like to try my teas using a clay boiler to heat my water, and compare the clay boiled water with water from another heating method. Clay boiled water is very nice with drier storage puerh teas. By contrast, I prefer to use small clay teapots for steeping wetter stored teas, and then I don’t need clay boiled water. 


  1. Do you know of any variable temp clay kettles? Perhaps it can currently only be done using a coffee warmer type of device below the kettle?

    1. I do not know of any except for those which have the warmer device that the kettle sits on.

      However it might be worth taking a look at just the warmer itself. I looked into a number of portable warmers to go with the Lin's boiler when I thought it could not be used on a gas stove. Later I heard from tea friends that they were using clay boilers on gas with no issues, so I dropped the idea of buying a small warmer. Aliexpress has many to choose from.

  2. Ha. I didn't know you could use those chaozhou clay kettles on a gas range stove! I've been using mine exclusively with a chaozhou stove. Perhaps as long as the heat isn't too high? I was suggested not to use my yixing kettle on a gas range stove so I assumed that was the case with other handmade ceramic kettles. Would be nice to use them indoors.

    1. Thank you for your thoughtful comments and for reading the blog :)

      I know that Yixing Clay varies in quality and also in firing. That is, pieces may be fired at medium or high temperatures, usually geared toward different tea types, some of which may not use boiling water. Clay also may have impurities making it unsuitable for high temps. It is probably best to follow the instructions you were given.

      Having said that, my understanding is to choose a method of heating and stick to it for the life of the kettle. However, if your kettle has had some fairly hot heating with a clay stove in the past, most likely it would be fine indoors if the boiling water is poured in and then the whole kettle kept on a warmer. Might be worth checking out some of the infrared warmer plates on Aliexpress, or one of the candle warmers. At least in this way you could carry your kettle to a room and keep the water hot for brewing without needing to return to the stove.

  3. We must be kindered spirits, because I am obsessed with water heating for the tea preparation, and I am one of the few who has more than one tea kettle, I have a tetsubin, a Lin`s tea kettle, a glass kettle, and electric glass kettle, and a Japnaese Bofura, and a Shia Dao Chao Zhou clay kettle, and I am planing on buying an Anta pottery kettle from taiwansourcing, and later on a silver tea kettle. It is important what type of water you use and after that the material of your kettle is most infulential, and the teapot material, you can make one tea taste diffrent by switching the teaware, even if you use the same tea to water ratio.

    1. I think we are kindred spirits, as I have been seriously seriously tempted by the Anta kettle too. But I think I'm a crazy person, and you are confirming the objective value of tea kettles and water from a sane perspective. For sane people.

    2. Hi Cwyn,

      Thank you for sharing information on clay boilers. I own an Anta clay boiler and enjoying it a lot. The water comes out softer than my Tetsubin (which is double the price) - most detectable when the water has cooled down to room temp.
      Appreciate your shared thoughts, wit and experience.