Jun 11, 2025

How to Care for Nambu Ironware

Written by Team MUSUBI

Nambu ironware, or Nambu Tekki in Japanese, is a traditional craft from Morioka City in Iwate Prefecture, located 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, while the exterior of Nambu ironware is resistant to rust making it ideal for everyday use.

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

table of contents

Nambu Ironware Kettle Narashi: How to Season Your Nambu Ironware Kettle Care After Use If Your Ironware Kettle Gets Rusty Nambu Ironware Teapot Care After Use

Nambu Ironware Kettle

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.

Narashi: How to Season Your Nambu Ironware Kettle

Follow the instructions below to properly season your new kettle.

Step 1: Boil Water

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

Step 2: Repeat the Process

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.

Step 3: Ready to Use

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.

Care After Use

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 Your Ironware Kettle Gets Rusty

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 to remove any unpleasant metallic flavors or scent by the chemical reaction between tannins (tea polyphenols) and iron to help neutralize any metallic taste.

Nambu Ironware Teapot

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 fire or stove to boil water. This will cause peeling of the enamel. The 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 to polish enameled inside.

Care After Use

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.

Nambu ironware is a traditional Japanese creation, valued for its strength, durability, and carefully balanced design. And the kettle is especially prized as one of the finest tools for boiling water—ideal for preparing tea.

We hope a Nambu ironware kettle or teapot becomes a practical and enjoyable part of your daily routine.

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