Does Tomato Damage a Wok's Seasoning?

Question

I have been using a wok since some years, it is nicely seasoned and I was quite happy with it and the results.

Recently, I have started cooking some Indian dishes, and because I like my wok, I just made them in the wok. However, it seems like the tomato is removing the seasoning - there are more and more blank spots appearing. Can that be?
Is it maybe the acid in them? Or is it something else specific to the Indian recipes (I use typically tumeric, ginger, garam masala, chili, and of course garlic and onions, but I used those before for non-Indian recipes without issues).

Answer 1

From experimental evidence*: Yes. Wet and acidic braising sauces (as you have in indian cooking) that stay in the wok for a long time are quite aggressive on the seasoning. A contributing factor could be rapid thermal changes when cold, wet ingredients are added to a hot mixture.

Also, in many cases the seasoning in cookware used for sundry purposes isn't exactly perfect - there can be spots where there is very thin or no seasoning covered by carbon deposits which can be underwashed or soaked if the pan is flooded with liquid for a long time, both softening these carbon crusts and allowing the liquid to attack the metal underneath.

*An extreme example: making american-chinese style spring roll or pineapple sweet-sour - plenty of vinegar, fruit juice, tomato balanced by plenty sugar. Seen that take a significant amount of the seasoning off a cast iron wok within half an hour.

Answer 2

It could be, but it's probably not because of the acid specifically. The smallish amount of acid in tomatoes shouldn't have any direct effect on the polymerized oil which makes up the seasoning, and the polymerized oil should prevent the tomatoes from directly touching the reactive bare steel that the wok is likely made of.

Tomatoes do have a high water content which cools down the part of the pan they touch significantly. Combine that with the carbohydrate content of tomatoes and that's a recipe for getting stuck to your pan. Keep in mind: any time you have a food sticking to a seasoned surface, it's sticking to the seasoning, not the metal. When you try to move it, it's going to want to take some of that seasoning with it.

Other things to consider: Are the foods you're cooking wetter, stickier, or sugarier? Are they cooked at a lower temperature? Do they Require more scraping during or after cooking? Use less oil? If you previously did quick and hot stir fries in the pan and are now switching to simmering things, that could definitely loosen up the seasoning, even if it was hot water.

The answer could be as simple as really cranking the heat, making sure you're using enough oil, or using a different pan

Good luck!

Answer 3

It is the tomato and it is a known effect and it is related to the acidity. As for the comment above for a small amount of acid in tomato remember that a of organic acids are “weak” acids. That means that can produce similar acidity with lower amounts.

It is the same with the seasoning of cast iron pans or the seasoning of the french carbon steel pans. I have used my french carbon steel with tomato and the seasoning has gone but do not despair. If you want to continue using it just use it. The seasoning will go but after you wash it with water dry it with a tissue, wipe it with oil (i go for olive) and heat it and remove the extra oil with a tissue. If you cook a lot of chinese dishes and you use the wok with high heat, you will season it as you cook.