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How do you preheat a Cast Iron Skillet? Can you use the "water test" as with Stainless?

Hey Chowhounders,

I'm considering getting a cast iron skillet. I just made the switch from teflon to stainless and am thinking about going for cast iron.

I'm sure many of you have seen the videos here, particularly the first one in the blog post.

Is the process for preheating cast iron similar? Would you get a similar mercury ball / "Leidenfrost effect"? Is that even what you want when preheating cast iron?

If it makes a difference, I think I would just go with a Lodge chef's skillet, with the rounded sides.

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  1. I do use water test for my cookware regardless of the materials, that is including carbon steel, cast iron ... etc. I don't test exactly the same way. I test based on the sound of the water droplets -- how it sizzles.

    1 Reply
    1. re: Chemicalkinetics

      Yeah, I think you're overthinking it. Water still sizzles in cast iron. However, it does heat up more slowly. And, if you're new to cooking in a cast iron skillet, rememeber that the handle will heat up, so use a towel or potholder to grab it. You'll remember after the first time you grab that handle without one!

    2. Harold McGee has an interesting article on heat and pan materials. Toward the end he talks about heating oil in a pan (as is often recommended for stainless steel)


      1. Check this link for more videos in that series.


        The last one in the series addresses different pan types. It says CI is too porous for the mercury ball effect to work. I do use drops of water to test a CI pan temperature for cooking pancakes, but the drops dance across the surface then evaporate, which I believe indicates a hot enough pan for pancakes, but too low for chicken.

        IME a well seasoned CI pan is much less prone to sticking than SS or anodized Al, so pre-heating is more necessary for browning than to avoid sticking.

          1. I look for water balls when I heat up my iron skillet. I heat my pan on med heat until a drop of water balls as soon as it hits the surface of my pan. I've been putting my hand palm down above the skillet to get a feel for how the heat radiates off the pan, and I think in a while I'll be able to tell this without a drop of water. Which is what cooking is. You just try stuff. Luckily, you have this entire site of cooks to give you plenty of advice as you learn how to use a new CI pan.

            I love my CI pans. Using them has become a pleasure I never had in previous years of cooking.

            A Lodge skillet is a modest investment, which could last you a lifetime, with proper care. If all those old grannies in the 1800s who cooked on wood stoves can use an iron skillet, you can too!

            1. If you want to get in touch with your "inner geek", you could pick up a non-contact infrared thermometer. Accurate, instant readout, laser pointer -- truly a geek's delight. An IR thermometer is a surprisingly handy thing to have in the kitchen, and also surprisingly inexpensive.

              The picture shows one available from Amazon.com that costs only $22.99.

              I use a similar model to check the temperature of my Lodge grill pan before I drop in a nice thick steak.

              1 Reply
              1. re: tanuki soup

                IR thermos are great for checking your oven temp and are necessary for determining accurate temps of your grill.

              2. In the beginning allow yourself extra time to decide where the sweet spot is with your stove and the cast iron. Try a setting between medium and low and give it a good 5 minutes to heat up. Cast iron always can get hotter but it's more difficult to cool down. the mercury ball trick doesn't work with cast iron. Searing of meats will take a higher heat but that is very subjective as to how you like you meat cooked. I have found the rarer you like a steak the higher the heat and a short cooking time works for me.

                There are handle mitts that slip over the handles, they can be found online and at restaurant supply houses. Protects not only you but others that may go to move a "cool" pan.

                6 Replies
                1. re: SanityRemoved

                  Um, depending on what you mean by "mercury ball" test, I'd have to say that it works for me. I put a drop of cold water on a heated pan's surface and watch to see if the water drop goes immediately to a ball. I heat my skillet on medium heat. I agree with the part about learning what temp works best for your pan. I've noticed that the stove or a family member does not heat like my stove. You just have to learn.

                  1. re: sueatmo

                    Can I assume that your pan is very well seasoned?

                    1. re: cutipie721

                      Yes, my pans are seasoned and I maintain them pretty carefully. I think heating them on medium heat works well too.

                    2. re: sueatmo

                      In stainless steel the ball will act like mercury does if you spill it on a hard surface. Today playing with mercury is frowned upon as is making moustaches out of asbestos :)

                      1. re: SanityRemoved

                        "In stainless steel the ball will act like mercury does if you spill it on a hard surface. Today playing with mercury is frowned upon as is making moustaches out of asbestos :)"

                        LOL, I had to laugh at this as I remember how fun mercury was to play with. Sometimes a kid at school would sneak some in. i think they would get it out of broken thermometers. I was totaly facinated with it. Looks like someone could come up with something man made that was safe that would be like it.

                        As for checking the cast iron skillet to see if it is hot enough by dropping water on it. I do this too, but all I do is just see if it will sizzle when it hits. If it sizzles, I figure it is hot enough.(this has worked for me) I am so simple with my cooking, I guess. I never knew that 'how' the water sizzled gave more specific info on how hot the skillet is. Wow, who knew? Love this board.

                        1. re: dixiegal

                          In college I had a lab assignment that involved lowering a copper ball into a vat of liquid nitrogen, and watching the action as the ball cooled (and recording the temperature with a thermacouple in the ball). Initially the temperature contrast was so great that an insulating layer of vapor form around the ball. Later that layer started to break up, exposing more liquid to the 'hot' ball. For this brief time, the nitrogen boiled very rapidly. Then came another slow phase when nitrogen boiled slowly.

                          Water on a hot skillet does the same thing. If the skillet is very hot, the droplets will dance around on a vapor layer, and disappear slowly. For a slightly cooler pan, the droplets will boil away rapidly. And yet cooler, the water will form a sheet that gently boils away. And of course if below boiling it just evaporates.