Cast iron pot: seasoning and maintenance for lasting protection

This comprehensive guide explains how to maintain and season a cast iron cauldron to easily preserve its performance and prevent rust.

Maintaining and seasoning a cast iron cauldron

A cast iron cauldron is designed to last.
Its robustness, thermal inertia, and resistance to high temperatures make it particularly suitable for long cooking times. But this durability relies on one essential condition: simple and methodical maintenance.

Cast iron is an iron alloy rich in carbon (generally between 2 and 4%). It retains heat very well but is sensitive to moisture.

This behavior is comparable to that of carbon steels used for certain knife blades: without protection, they can oxidize. The difference is that, for a cooking utensil, this constraint is controlled through a natural surface treatment: seasoning.

A cast iron cauldron is easy to maintain

Reading time: ~ 4 min

What is seasoning for?

Seasoning refers to the formation of a thin protective layer on the surface of cast iron when a small amount of oil is heated to around 220–250°C. Under the effect of heat, the oil molecules decompose and chemically bond to the metal, forming a solid network: this is the polymerization phenomenon. This layer is anchored in the metal—it is not just a superficial deposit.

It plays a dual role: protecting the cast iron from oxidation and progressively improving its surface properties by reducing food adhesion. With each use involving a fatty substance, a new microscopic layer polymerizes over the previous ones—which is why a regularly used cauldron naturally becomes more and more effective.

A well-done seasoning results in a matte, dark, and slightly silky surface to the touch—not shiny, not greasy. The color darkens over time: this is a good sign.

Highly acidic foods (tomatoes, wine, citrus) can weaken this layer, especially on new seasoning. It's best to avoid them during the first uses.

Good seasoning is not a thick varnish. Too much oil becomes sticky, forms irregular deposits, and leaves greasy spots. This is the most common mistake.

↑ Back to summary

Our cauldrons are already seasoned

Our cauldrons are already prepared for immediate use over a fire.

However, it is entirely possible to add another layer of seasoning, if you wish, to further enhance surface protection and improve the cooking experience.

I want to cook in a cauldron!

↑ Back to summary

When should you re-season?

It is not necessary to completely re-season after each use!

However, it becomes relevant in several cases:

if the surface becomes dull, grayish, or dry;
if the cauldron has been cleaned too aggressively;
if food sticks abnormally despite proper cooking;
if rust spots appear.

Important:
if food sticks, the cause is not always poor seasoning. Cast iron that is too hot or cooking with insufficient fat can also cause sticking.

↑ Back to summary

How to season properly

Here is a simple and rigorous method:

clean the cauldron;
dry it perfectly;
apply a very thin layer of cooking oil over the entire surface;
wipe off the excess;
heat until the oil reaches its smoke point (it polymerizes around 220-250°C);
let cool;
repeat if necessary.

The quality of the result depends less on the amount of oil than on the thinness of the application and the consistency of the heating.

↑ Back to summary

Which oil to use?

To season, a vegetable cooking oil, such as rapeseed oil, is generally used.

A common misconception is that animal fats should be avoided because they might turn rancid. This is scientifically inaccurate in the context of seasoning. Once heated to high temperatures and polymerized, the oil is chemically transformed: it can no longer turn rancid.

The essential idea remains the same: choose a cooking oil and apply it in a very thin layer. Some specialists advise against linseed oil, which can quickly give a beautiful initial coat but tends to flake off with use.

↑ Back to summary

Cast iron cauldron and brush kit made of beech wood and 100% natural fibers. Approche Libre

I want a three-legged cast iron cauldron

Routine cleaning: the right method

1. Let the temperature cool down

It is essential to let the cauldron cool down before any water cleaning.
Avoiding thermal shocks remains an important rule for any cast iron piece.

2. Clean with hot water

In most cases, hot water and a brush are sufficient to clean the cauldron.

For more stubborn residue, our Two Beech FSC® Brushes – Natural Fibers Kit cleans effectively without stripping the surface.

3. Use appropriate brushes

To preserve the seasoning, it is essential to use an appropriate tool.
Too aggressive cleaning (abrasive sponge, chemical product) can damage the protective layer and expose the cast iron to oxidation.

The ideal is to use a natural fiber brush, firm enough to dislodge residue, but without damaging the surface.

It is with this in mind that we designed our kit of beech wood and plant fiber brushes :

a firm brush (sisal + palm) to effectively clean the cauldron;
a softer brush (sisal) to apply oil and maintain the seasoning;
100% natural fibers, plastic-free;
FSC® certified beech wood, durable and resistant.

Thanks to their shape, these brushes are particularly suited to concave surfaces like the inside of a cauldron.

4. Limit soap

Soap is not systematically forbidden, but intensive use can weaken part of the seasoning's protective layer. A few drops of liquid soap are enough and pose no problem.

↑ Back to summary

Drying: an essential step

Cast iron should never remain damp.
After washing, it must be wiped dry immediately.

This is one of the most important steps to prevent rust.

↑ Back to summary

Light oiling after cleaning

Once the cauldron is perfectly dry, a thin layer of vegetable cooking oil can be applied.

Do not leave a thick, visible greasy layer. The goal is simply to apply a very light protective film, then wipe off any excess. Too much oil promotes sticky surfaces and irregular deposits.

For this step, using our soft sisal fiber brush allows the oil to be applied evenly, without excess, over the entire surface of the cauldron.

↑ Back to summary

I want the cauldron maintenance kit

What to do in case of rust?

Rust is not the end of the cauldron.

If it appears:

scrub the affected area;
clean;
dry perfectly;
re-season completely.

For rusted cast iron, more vigorous washing, including with soapy water, is acceptable as the goal is to get back to a clean base before re-seasoning.

↑ Back to summary

The most frequent mistakes

Problems encountered with cast iron often stem from poor practices:

leaving moisture after washing
using too much oil
believing that thick seasoning is better
washing too aggressively
storing the cauldron in a damp place

Well-maintained cast iron doesn't require complicated actions, but simply good practices.

↑ Back to summary

Why use appropriate brushes?

Mechanical maintenance of cast iron must be effective without being harsh.

That's exactly the purpose of our two-brush kit in FSC® beech – natural fibers:

a firm brush to remove residues;
a softer brush to spread the oil cleanly.

Durable Brush Kit for Approche Libre Cauldron Maintenance

A well-maintained cast iron cauldron does not require complicated actions, but precise ones.

With a simple and mastered method, cast iron retains all its qualities over time and continues to offer reliable and durable cooking for many years.

↑ Back to summary

I want the cauldron maintenance kit

FAQ

Are Approche Libre® cauldrons already seasoned?
Yes. Approche Libre® cauldrons are already seasoned, so they are ready to use upon receipt. It is then important to maintain them well to preserve their protective patina permanently.

Why should a cast iron cauldron be seasoned?
Seasoning creates a thin protective patina on the surface of the cast iron. This layer limits oxidation, improves cooking comfort, and facilitates cauldron maintenance over time.

Why does my cauldron become sticky after seasoning?
This most often happens when the oil layer is too thick or insufficiently heated. It's better to wipe off the excess and reapply a much thinner layer.

Can a well-maintained cast iron cauldron last a long time?
Yes, for a very long time. With proper seasoning, careful drying, and regular oiling, a cast iron cauldron can accompany you for decades for cooking over a wood fire.

↑ Back to summary