How to Season a Cast Iron Wok: A Complete UK Guide

The right way to season your wok the first time — and how to keep it black, glossy, and non-stick for decades.

A cast iron wok isn't like a non-stick pan. Out of the box, it's raw iron — prone to rust and far from non-stick. Season it correctly, though, and you build a natural, polymerised oil coating that gets better with every stir-fry. This guide walks you through the seasoning process step by step, covers what not to do, and answers the questions UK cooks ask most.

What does "seasoning" actually do?

Seasoning is the process of bonding a thin layer of polymerised oil to the wok's surface. When you heat oil past its smoke point on raw iron, the oil molecules cross-link and fuse to the metal, creating a hard, water-repellent, naturally non-stick coating. Every time you cook with oil, you add another microscopic layer — which is why a well-used cast iron wok goes from dull grey to jet black over time.

A properly seasoned wok:

• Won't rust (the polymer coating blocks moisture)
• Releases food cleanly (no sticking for fried rice or stir-fry)
• Adds subtle depth of flavour to everything you cook
• Outlasts every non-stick pan you'll ever buy

What you'll need

• A raw cast iron wok (your 32cm Chinese cast iron wok is ideal — flat bottom means it works on both gas and induction)
• A high smoke-point oil — flaxseed, grapeseed, or rapeseed oil. Avoid olive oil (too low smoke point) and sesame oil (too delicate)
• Kitchen roll or a lint-free cloth
• Oven mitts
• A well-ventilated kitchen (open the window — seasoning smokes)

Step-by-step: season your cast iron wok

Step 1: Wash and dry

If your wok came with a factory protective coating (usually wax or mineral oil), scrub it off with warm water and a few drops of washing-up liquid. This is the only time you'll ever use soap on your cast iron wok. Rinse thoroughly. Dry immediately with kitchen roll — don't let it air dry, even for a minute, because raw iron will flash-rust.

Step 2: Heat the wok dry

Place the wok on your highest-powered burner (or induction ring on max) and heat until any remaining moisture evaporates and the iron starts to shimmer. You'll see the metal change colour slightly — blueish tones around the edges are normal and desirable. This takes 3-5 minutes on gas, slightly longer on induction.

Step 3: Apply the first oil layer

Turn the heat off. Pour ½ teaspoon of your high-smoke-point oil into the wok. Using folded kitchen roll held with tongs (it will be hot), wipe the oil thinly around every interior surface — including up the sides. Then wipe it off. Yes, wipe it off. You want the thinnest possible film. Too much oil = sticky, uneven seasoning.

Step 4: Heat past the smoke point

Turn the heat back to high. The wok will start to smoke. This is the oil polymerising onto the iron. Let it smoke for 3-5 minutes until the smoking stops. The surface should go from raw grey to a matte brown-black. Turn off the heat and let the wok cool for 10 minutes.

Step 5: Repeat two or three more times

One seasoning layer is never enough. Repeat Steps 3 and 4 at least two more times — each time the wok gets darker and the coating more durable. Three rounds is good; five is better.

How to maintain the seasoning

Day to day, the rules are simple:

1. Never use soap again. Soap strips the polymerised oil. Hot water and a stiff brush is all you need.
2. Dry immediately after washing. Don't let water sit on the surface.
3. Cook with oil every time. Every stir-fry adds a micro-layer of seasoning.
4. Store dry, ideally with a light film of oil wiped on after drying.
5. If you see rust, don't panic — scrub it off, dry, and re-season that spot. The whole wok doesn't need redoing.

Common mistakes to avoid

• Using olive oil for seasoning — smoke point is too low. It'll burn without polymerising properly.
• Too much oil at once — creates a sticky, gummy residue that flakes off.
• Cooking acidic foods early — tomato sauces, vinegar, and wine can strip a young seasoning layer. Wait until you've got 10+ uses on the wok before trying acid-heavy recipes.
• Soaking the wok in water — rust in minutes. Even leaving it wet in the sink overnight is a problem.
• Putting it in the dishwasher — never. Ever.
• Stacking other pans inside it — metal-on-metal scratches the seasoning.

Why a cast iron wok beats non-stick for stir-fry

Non-stick pans have a ceiling temperature of around 230°C — above that, the PTFE coating degrades. Proper stir-fry needs wok hei, the smoky "breath of the wok", which only appears above 280°C. Cast iron laughs at that heat. It holds it evenly and lets you get the char you actually want on your vegetables and meat.

A good cast iron wok also has inertia — drop cold ingredients in and the wok keeps its heat, so your food sears instead of steams. Non-stick pans dump their heat instantly.

And unlike non-stick, cast iron gets better the more you use it. A cheap non-stick is a two-year lifespan. A well-seasoned cast iron wok outlives its owner.

Frequently asked questions

How often should I re-season my wok? If you use it every week and maintain it properly, the seasoning self-repairs with every oily meal — you shouldn't need to do a full re-season. If it's patchy, sticky, or rusty, do a single oil-and-smoke pass to refresh it.

Can I use a cast iron wok on an induction hob? Yes — as long as the wok has a flat bottom, which the 32cm Chinese cast iron wok does. Round-bottom woks won't sit on induction rings.

Can I put my seasoned wok in the dishwasher? Absolutely not. The detergent will strip the seasoning in one cycle. Hot water, stiff brush, towel dry.

Why is my wok sticky after seasoning? You used too much oil. Heat it dry again until the stickiness carbonises, scrub the residue off, and re-season with a much thinner oil layer next time.

What's the best oil for seasoning? Flaxseed oil gives the hardest finish but is expensive. Grapeseed and rapeseed are cheaper and work well. Avoid olive oil, butter, and any flavoured cooking oils.

Can I use my seasoned wok for acidic foods like tomato sauce? Once the seasoning is well-established (20+ uses), yes. Early on, acid can strip a young seasoning — stick to oil-based cooking for the first month.

How long does it take to build a good seasoning? An initial 3-round seasoning takes about 45 minutes. Building a proper black, glossy patina takes 20-30 meals. After a year of regular use, your wok will be blacker than the day you bought it.

Do I need to season a pre-seasoned wok? Even pre-seasoned woks benefit from one round of home seasoning before first use — it bonds the factory coating more firmly and adds a layer of your chosen oil.

Ready to start?

If you haven't got your wok yet, our 32cm Traditional Chinese Cast Iron Wok is hand-hammered, flat-bottomed for induction and gas, and ships free within the UK. It arrives uncoated — so you'll be doing Step 1 of this guide on day one.

If you already own one and it's looking rough, start the 3-round seasoning process above tonight. One evening of effort, decades of better stir-fries.