The zero waste guide to cast iron

Cast iron pans are not nearly as popular as they used to be; compared to Teflon coated nonstick pans, they seem finnicky, sticky, and heavy. Cast iron is not difficult to use, but it does take a some practice to get used to. I’ve been cooking with cast iron for about six months now, and I’ve seen a lot of interest from my Instagram followers in how I’ve managed to use and maintain my pans and reseason particularly difficult cast iron.

Some people accuse Teflon style nonstick pans of being toxic or dangerous, but I’m not here to scare you into going zero waste; the consensus at the moment is that Teflon coated nonstick pans are safe to use. Teflon has been evaluated by as not suspected of causing cancer. One common ingredient in nonstick coatings, called Perfluorooctanoic acid (PFOA) has been suspected as being linked to cancer, although very little of the substance is actually present in the final products because it’s burned off during the manufacturing process. PFOA is not classified by the EPA as a carcinogen despite some evidence suggesting possible cancer causing effects in animals. At the moment, there’s not enough information to certainly say that the substance is a carcinogen in humans. The International Agency for Research on Cancer has determined PFOA to be a possible carcinogen to humans, but only possibly, due to limited evidence in both humans and animals suggesting its cancer causing effects. In all, not all studies have found links between PFOA and cancer, so more research is necessary to definitively say if there is a connection or not. 

This article cites a consumer safety officer at the FDA, and environmental toxicologist, and various other PhDs who all agree that nonstick pans are safe to use. Even if small amounts of nonstick coating are ingested, it’s thought to be harmless. There is concern when nonstick coatings like Teflon are heated to extremely high temperatures and give off dangerous fumes, but not for regular use and cooking. This can be avoided by using some oil when heating pans, which will smoke before the pan reaches dangerously high temperatures.

So even if typical nonstick cookware isn’t going to kill you, there are plenty of reasons to use cast iron instead. Cast iron pans will last a lifetime if taken care of properly, and possibly even if they’re abused and neglected. Cast iron can even be a way to introduce more iron to your diet if that’s a concern, as food cooked in cast iron can absorb some from the cookware. Cast iron is incredibly durable as well, and nearly impossible to ruin.

So if you plan to make cast iron a part of your zero waste lifestyle, check out the following guide:

Sourcing cast iron

Cast iron cookware has been around forever, and if you’re willing to be patient, there’s no reason you’d need to purchase it firsthand. First, ask family and friends if they have any cast iron because people often purchase cast iron or are given cast iron but don’t know how to use it. The food sticks, and the pan gets tucked away and forgotten; there’s a chance someone you know would be happy to get rid of their unused, heavy resource.

If nobody you know is passing up on their cast iron, check secondhand home stores, thrift stores and antique stores. New cast iron can vary in price, but good quality pans are often expensive. Secondhand, cast iron is likely to be a bit more expensive than typical nonstick pans, but you’re more likely to get a quality pan for a lower price. That being said, it turns up commonly at thrift stores, so if you want to switch over to cast iron, I suggest starting to look before your current pans are unusable. I find older pans tend to be heavier, which can be a pain for lifting and transferring food, but heavier bottomed pans distribute heat more evenly. When it comes down to where to look, I suggest looking at antique stores if you’d like something with a heavier bottom, and thrift stores and secondhand home stores if you want something newer and lighter.


When picking your pan, be aware of the above information regarding the heaviness of the pan. There is no reason to shy away from pans with rust, because it can be easily removed. A pan with a relatively smooth cooking surface is ideal, but if the surface is cloudy rather than glossy or slightly rough, there is nothing to worry about. If you find a pan with hardened drips or raised bumps, be aware that this is from previous uneven seasonings of the pan and is most likely fixable. The good thing about cast iron is that, unless it somehow has a deep scratch, it can be rescued from almost any condition.

Seasoning cast iron

New or used, cast iron should be seasoned when you buy it. Begin by scrubbing the pan with soap and something abrasive. If the pan isn’t coming from someone you know, I suggest removing as much of the previous seasoning as possible; pans are porous and therefore some of the oil involved in cooking is absorbed into the top of the pan, which is what makes it nonstick in the first place. Most cast iron pans will be dull, not shiny, after the seasoning has been taken off. Any cloudiness should be generally gone, and the pan should be relatively even and uniform in appearance. Cast iron should not be left to air dry, so either towel dry your pan or dry it by putting it on a hot stove until the water evaporates.

Seasoning the pan is as easy as rubbing a very thin layer of a non-animal fat on the surface with a cloth and baking the cast iron for an hour between 350 and 425 degrees Fahrenheit. While some recommend turning the pans upside down so any excess oil drips off, this won’t be an issue if you use a thin enough layer of oil on the surface of the pan. As for the exact time and temperature of the oven, I’ve found no difference between a cooler or hotter oven on the results of the seasoning- leaving the pan in a hot oven for about an hour will do the trick. The oil bonds to the surface of the pan, making it smooth, shiny, and nonstick.

Since the pans are porous, repeating the seasoning with oil in the oven can create a thicker nonstick layer. Some pans season more easily and only need one seasoning to be nonstick, while other pans may need to be seasoned three or four times before they are truly nonstick. If you try and cook with your pan after one seasoning and food sticks, simply scrape it out and begin the seasoning process again.

While it’s fine to cook with animal fats in your cast iron, butter and lard shouldn’t be used to season. These oils can become rancid, which is undesirable for your cookware. I always season my pans with vegetable oil, and I find it gives a better seasoning than vegetable shortening. Flax seed oil is often hailed as the best for seasoning cast iron, but I’ve never had issues using vegetable oil instead.

Trouble shooting

Tacky surface

If the cooking surface of your pan is tacky or sticky, it was probably seasoned with too thick a coating of oil. Use less the next time or start over again.


If there are any bubbles or drips, this is also a sign that too much oil was used, causing it too pool. While drips on the outside of the pan are harmless, I wouldn’t suggest leaving them on the cooking surface.

Food sticks

If food is sticking to your pan, it may need more seasoning, but the best way to keep a cast iron pan nonstick is to use it regularly. Be sure to cook with a generous amount of oil, more than you’d use for a Teflon pan, for the first uses of a pan that sticks and the food shouldn’t stick anymore.

cloudy surface

I find the more frequently I wash my pans with water, the cloudier the surface becomes. Some visible texture on the cooking surface is fine as long as it’s not rough to the touch and the overall appearance of the pan is not flat.


As above, the best way to keep your cast iron in good condition is to use it. Use your cast iron regularly and reseason it as necessary. An easy way to season your pans without planning is to oil them and add them to the oven whenever you bake something. Many people swear by rubbing a layer of oil on the cooking surface after each use, which helps keep the pan from rusting and I find helps maintain the nonstick surface.

It’s not recommended to frequently wash cast iron. Unless you’re trying to start from scratch and ruin the seasoning on the pan, soap shouldn’t be used to clean your cast iron. Instead, scrape out food or crumbs if you cooked something relatively dry, and scrape and clean with water for anything on the wet side, like a sauce. When you do clean with water, don’t let your pan air dry or it may rust. Instead, dry it with a towel or place in on a hot stove to evaporate the leftover drips of water.

Cooking tips

  1. Until you’re comfortable using your pan, it doesn’t hurt to use some extra oil when you cook to prevent sticking.

  2. A metal spatula is ideal for learning to cook with cast iron. The oil between the pan and the food creates a slightly crispy layer, and a thin metal spatula most easily lifts the food from the pan. An even release prevents food from getting stuck.

  3. Don’t try and constantly move the food around the pan. Let it cook until it needs to be turned or moved. Moving food before it’s had a chance to start cooking, it won’t release easily from the pan and you’ll have burnt food on the bottom of the pan.

  4. Cast iron gets hot and stays hot, especially if you have a heavy pan. Be aware that if your pan gets too hot and begins to burn the food, it won’t cool down as quickly as a typical pan and will keep that too-hot temperature longer than desirable.

  5. Self-explanatory, but the handle will get very, very hot, so keep an oven mitt or potholder around when you’re cooking.  

  6. Cast-iron pans must be hot before you put the food in them for the same reason a metal spatula is best for learning to cook with them; it helps the food release if it’s put into a hot pan. I recommend putting the pan on medium heat for a few minutes before you’re ready to cook. It may smoke if it gets too hot without food, but this will take a while.

  7. Sometimes cast iron may be grey rather than the traditional black, which is normal and may be due to a new pan or a pan that has been cleaned excessively. If you’re starting with a grey pan or your pan grays on the inside from cleaning, you may find there’s a longer period of trouble with the pan before it’s dependably nonstick.

Happy cooking!