Building a rich patina of seasoning over a cast iron pan is an immensely satisfying experience.
So, when I saw an old, rusty cast iron Kadai at my mom’s place, I was excited. It was so old with cobwebs that I was sure it would be an excellent opportunity to explain the process in-depth.
Whether you are seasoning an unseasoned pan or re-seasoning an existing one, you can follow the process described below.
Rust is the nemesis of cast iron. The first step when seasoning an old pan is to remove as much rust as possible. You can do this by pouring a few drops of Vim liquid and scouring it with steel wool or an abrasive scrub. Then, wash it in running water.
Many cast iron aficionados would be irked at the thought of using soap on cast iron. But, in my six years of experience using cast iron utensils, I have never found soap damaging to cast iron.
I have read some bloggers saying just like how soap cuts through grease, it cuts through the seasoning which is formed by heating oil. But, it doesn’t make much sense because when heating, oil polymerizes and bonds with iron to form a layer of seasoning. Soap can’t dissolve this layer. Only excessive heat, abrasive scrub and acidic food can damage the seasoning.
I digressed. So if the rust persists, you can use sandpaper. But, you needn’t worry too much about tiny streaks of rust as the seasoning will be formed on top of it.
Once you removed as much rust as possible and cleaned the cookware, heat it on the stovetop so that it is bone dry. Cast iron is porous. Upon heating, the metal expands and opens up the pores. This helps the pan to absorb the oil better resulting in even seasoning.
Note- You should scour the pan even if you are seasoning a new unseasoned cast iron cookware bought from a local shop as it is likely to have a coating of wax or shellac to prevent it from rusting.
Related reading: Cast Iron Vs Iron Cookware- Similarities and Differences
Seasoning Cast Iron On Stove Top
My favourite tool for applying oil is a silicone oil bottle with a basting brush. It is handy and very easy to use. I use this for oiling the pan for seasoning as well as while making dosas.
Most experts from the West swear by Flaxseed oil for seasoning. But, it isn’t something we use commonly in Indian kitchens. I have instead used Sesame oil. Soybean or any other vegetable oil works fine as well.
Once the pan is dry and manageable warm, apply a thin layer of oil using the silicone brush all over it. Ensure that you cover the cooking surface, bottom, handles and every cranny of the cookware.
Once oiled, leave it aside for 5-10 minutes so that the cast iron absorbs the oil. Then using a paper towel or a napkin, wipe off any excess oil. This is crucial to prevent the cast iron from developing a sticky surface. Unseasoned cast iron pans especially have bumpy surfaces in which oil could get pooled. So, ensure that it is all wiped thoroughly.
Then place the cookware on the stovetop and heat it on the highest flame till the oil starts smoking. This is when the oil polymerizes and bonds with the metal to form the seasoning.
When you heat on the stovetop, the bottom of the Kadai gets heated quickly. But, it takes a while for the edges to get hot enough. So, there is a possibility that the bottom develops a slick nonstick-like surface while the edges have a gummy/sticky surface. This is normal.
Switch off the flame within 2-3 minutes of the oil smoking. Else, the seasoning could get burnt and leave brown-black residue on the pan. Altogether, you will have to heat the cookware for just 10-15 minutes maximum.
If it is a new pan or if the seasoning has drastically worn out, repeat the seasoning process 2-3 times. Ensure that the pan cools down completely before you repeat the process else, it will have a sticky surface.
Read more: Which Type of Cookware Is Best For Health?
Maintaining Cast Iron Cookware
Maintaining cast iron cookware isn’t as demanding as many allege.
After cooking, wash it with dishwashing liquid and a non-abrasive scrub. Then, dry it either on the stovetop or using a kitchen towel. Apply a thin layer of oil and store it away. If you use the cast iron cookware on a daily basis, you needn’t apply oil before keeping it in the kitchen cabinet.
Never wash cast iron in the dishwasher it strips off the seasoning.
Season the cookware whenever you find it has flaked off or if you find its surface bumpy.
Related reading: Why Does Food Turn Black In Cast Iron Cookware?
Common Problems of Cast Iron Cookware
Cast iron pans are prone to rust. You can remove the rust by scouring it with soap and a moderately abrasive scrub. If it is a pan that you haven’t used for a really long time, you can use sandpaper to remove stubborn rust.
Food Gets Stuck On
Food is likely to get stuck on your pan until it develops a proper layer of seasoning. When food gets stuck on it, scrub it off with a nylon brush and season the pan if necessary.
Many novices have given up on cast iron Tawa because Dosa would get stubbornly stuck on it. To avoid this, apply a thin layer of oil and heat the Tawa on a low flame. In the meanwhile, you could prepare the chutney. By the time the chutney is ready, the Tawa develops a layer of seasoning that ensures the dosa doesn’t get stuck on it.
Sometimes, when you wipe the cast iron pan with a paper towel, you find brown or black residues. This is quite common. Many experts say it isn’t a problem and that you can cook on it.
A common reason why this happens is improper seasoning or if the seasoning gets burnt off. Season the cookware once again and you should be able to get rid of the brown-black residues.
Sticky surface is a common problem faced when seasoning cast iron cookware. The culprit is excess oil.
When you apply oil and heat it on a cast iron cookware, the oil starts smoking. This results in thermal polymerization of the oil, whereby it gets bonds with the surface to create a slick layer.
When there is excess oil on the pan’s surface, it won’t get polymerized properly resulting in a sticky surface.
To resolve this, heat the pan again for 5-10 minutes so that the polymerization process is complete. If you are seasoning a Tawa, you may have to carefully move it around so that the edges too get heated properly for the oil to polymerize.
Read more: 10 Essential Cookware Every Kitchen Needs
Common Myths Around Cast Iron Cookware
Cast iron seasoning gives it a nonstick surface
Unseasoned cast iron cookware has a rough and bumpy surface. When seasoned, it develops a black layer that is smooth and glossy.
But, it won’t be as nonstick as a Teflon coated pan. No matter how much you season it, you have to add sufficient oil before cooking on a cast iron pan or Kadai else, food will get stuck on it.
A well-seasoned pan won’t get rust
Cast iron is porous. So, no matter how well you season it, the iron inside could get exposed and when it gets in contact with water, rust could develop. So even if the pan is well-seasoned, it could develop rust if it is exposed to moisture.
This shouldn’t deter you from using cast-iron cookware as you can scour and remove the rust easily.
Seasoning cast iron on the stovetop isn’t as effective as an oven
It is true that the oven can heat the entire pan to a uniform temperature. But, it is slow and the temperature attained is low. Typically, it takes about an hour to season a cast iron cookware in the oven.
On the stovetop, the cookware is subject to a higher temperature. So, it gets seasoned quicker. Moreover, as you notice the pan getting drier, you can apply another coat of oil and hence build a thicker layer of seasoning which would be more durable.
Cooking in a cast iron pan can alleviate anaemia
If you cook in a well-seasoned cast-iron pan, your food won’t have significant contact with iron. The iron that leaches into the food is less to have an impact on your dietary intake. You can read our article here to know more about how to maximize the iron content of food cooked in cast iron cookware.
Cast iron heats evenly
Cast iron isn’t loved by chefs for its uniform heating, but for its heat retention capacity which helps cook thoroughly and create a nice crust on the surface. So, you can make crisp dosa, well-seared fish, steak etc. But, it doesn’t heat uniformly.
In fact, compared to Aluminium, it takes a longer time for the heat to get transferred throughout the pan. Most cast iron pans also have hot spots, which means, a particular spot could get hotter than the rest of the surface.
You have to season cast iron cookware frequently
The seasoning on cast iron pans can be damaged if it is heated to a high temperature. It could also get flaked if acidic food is cooked in it.
But, whenever you cook with oil, a thin layer of seasoning develops on the cast iron pan. So, using them regularly is enough to maintain the seasoning unless it is damaged by any other means.
Congrats! You are a cast-iron champion!
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Your cast iron rusted 🙁
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#1. Which of the following DOESN'T affect transfer of iron to food cooked in iron cookware?
The use of oil doesn’t affect iron transfer from cast iron to food!
#2. True or False: Rusted cast iron pans should be discarded.
Rusted cast iron cookware can be washed, cleaned and seasoned to be used again! Cast iron can last decades with proper care!
#3. Which of the following oils shouldn't be used for seasoning cast iron pans?
Mineral oil should not be used for cooking purposes!
#4. True or False: Cast iron shouldn't be washed with soap.
Washing cast iron pans with soap doesn’t affect its seasoning. Just take care to use a soft non-abrasive scrub!
#5. True or False: Cast iron heats uniformly
Contrary to popular opinion, cast iron doesn’t heat uniformly. Hot spots are very common in cast iron pans. Chefs love cast iron pans for their heat retention ability and not for uniform heating!