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I have an iron kettle that I use for boiling water. Everyone says not to use an open gas flame when boiling for fear that it will cause rust in the future. I also have a set of copper diffusers that I sometime use when I am cooking with my CI pots and pans. My question is if I use them when I boil water in my iron kettle, will it cause harm. I think it will definitely take longer to boil water.

Webley wrote: ↑

Wed Jan 27, 2021 9:30 pm

I have an iron kettle that I use for boiling water. Everyone says not to use an open gas flame when boiling for fear that it will cause rust in the future. I also have a set of copper diffusers that I sometime use when I am cooking with my CI pots and pans. My question is if I use them when I boil water in my iron kettle, will it cause harm. I think it will definitely take longer to boil water.

Everyone is not the most reliable source of information... I for one am not everyone and quite happily using a gas stove to heat my Tetsubin. Does it rust? Sure but what do you expect from cast iron? No one said it’s a maintenance, care free item. Iron need constant usage and taking care of.

Nothing that can’t be fixed with tea/rice/lemon boiling.

Bok wrote: ↑

Thu Jan 28, 2021 12:12 am

Everyone is not the most reliable source of information...

This is a very important thing to keep in mind.

Can't see how a copper diffuser would cause any harm to the tetsubin. It's going to spread the heat more evenly, which is a good thing. Then again, not sure if it's really necessary (for either CI cookware or a tetsubin). Since you already have the diffusers, I'd just check how much extra time using one adds to the boiling process and then weigh that factor against how much of a risk you consider exposing the tetsubin directly to a gas flame to be.

What kind of diffuser do you use? Can you share a picture?

The company is “Bella Copper” here in the U.S. they have different sizes. They’re a little pricey, but if you have a use for them go for it. The owner is very nice and will explain everything about them. I use mine quite a bit as you can see from the spotting. They have a You Tube channel and the website is very explanatory.

That's a really nice copper plate, but i don't see any benefit in using it with the kettle. It will just make the heating slower and less effective. It is true that gas burning produces water vapor, but once the kettle is warm the heat will be drying it at the same time. Rusting mostly happens if the pot sits humid and cold somewhere not when it is on the fire.

Your reply makes perfect sense. Since I don’t turn the gas on high while I’m boiling water, I’ll continue using it on medium and observe the results.
I use the copper plates mainly for diffusing the burner flames evenly on my CI pots and pans. The pans have a tendency to cook hot in the middle and not the sides, which is inherent to their nature.

Indeed, with cast iron pans there is actually a risk of warping of the base on a strong flame because the heating is uneven as you say and the center may overheat. This shouldn't be a problem with a tetsubin because the water will take the heat away.

Just want to say that while everyone is not the best source of information (indeed!), my Tetsubin began to rust within a few days of using it on a gas burner. It was a rather dramatic change actually. I stopped using gas and got a portable induction cooktop instead, which is basically dedicated only to boiling water in the tetsubin.