How to Care for Nambu Ironware

Nambu ironware, known in Japanese as Nambu Tekki, is a traditional craft produced in Morioka City and Oshu City in Iwate Prefecture in the Tohoku region. Known for its coarse texture, this ironware is made using sand casting molds, giving each piece a distinctive surface. The iron body conducts heat evenly and retains warmth effectively.

Learn how to properly care for your Nambu ironware so you can continue using it for years to come.

Before using your Nambu ironware kettle for the first time, it’s important to season it—a process known as narashi in Japanese. This creates a thin layer of minerals inside the kettle that reduces the risk of rust and gives the boiled water a smoother, more mellow taste.

Follow the instructions below to properly season your new kettle.

Pour in mineral water (hard water) or drinkable tap water until the kettle is about 80 percent full. Boil it down to about one-third of the original amount, taking care not to let the kettle boil dry.

Discard the water, refill the kettle, and repeat the process three to four times, or until the boiled water becomes clear. The exact number of repetitions may vary depending on the water quality.

Once the water boils clear, your kettle is ready to use.

Tips:

• Never let the kettle boil dry.
• Avoid touching the mineral film that forms inside the kettle.
• Use care when handling—the kettle gets very hot.

After each use, pour out any remaining hot water. Any water left inside and allowed to cool may cause rust.

After draining, remove the lid and let the kettle dry completely using its residual heat or by placing it over low heat for about thirty seconds to speed up the drying process.

It is important not to leave any moisture inside the kettle. Even with the protective film formed during seasoning, long-term moisture exposure can lead to rust.

To protect the inner film, do not scrub or touch the inside. There is no need to wash the inside with detergent.

To clean the outside surface, simply wipe it with a dry cloth, especially around the lid and spout.

If you notice red rust inside the kettle or a metallic smell in the boiled water, don’t worry—it’s not harmful to your health. However, if it bothers you, try the following method:

Lightly rinse the inside of the kettle with water, then fill to about 80 percent. Add about one teaspoon of green or black tea leaves. Boil uncovered over low to medium heat for about 30 minutes, adding water if needed. Discard the tea and leaves afterward.

This method helps remove the metallic taste and scent through a reaction between tannins (tea polyphenols) in the tea and the iron.

Ironware teapots retain heat well, much better than glass or ceramic teapots, which makes your tea time more pleasant.

Unlike kettles, most ironware teapots have an enamel coating on the inside, so there is no need to season before use. All you need to do is rinse the inside of the teapot and the tea strainer thoroughly with warm water before use.

A Nambu ironware teapot must not be placed over an open flame or stove to boil water. This will cause peeling of the enamel. An iron teapot should only be used for making tea, in the same way as a ceramic or glass teapot.

Tips:

• Do not boil water with an iron teapot.
• Do not use metal scrubbers on the enameled interior.

After use, rinse the inside of the teapot and the tea strainer well with water or warm water, and wipe the entire surface completely dry with a dry cloth before storing.

Leaving water on the surface can cause rust, but the rust that occurs is not harmful to your health.

If you want to remove tea stains from the inside, pour boiling water inside and let it sit for a while, then clean it with dishwashing detergent and a soft sponge.

To clean the outside surface, simply wipe it with a dry cloth, especially around the lid and spout.

Crafted to support traditional iron kettles, these sturdy trivets are equally suited for teapots, pots, and ovenware. Their refined openwork forms and matte black finish complement both Japanese and Western table settings, while discreet rubber feet protect surfaces from heat and scratches—making them as functional as they are timelessly elegant.

To maintain its quality, allow the trivet to dry thoroughly and wipe away any remaining moisture before storing. Proper care helps prevent rust and preserves the integrity of the cast iron over time. Storing it in a well-ventilated, dry place will ensure lasting durability and allow the material to age beautifully.