Skip the Flaxseed Oil for Cast Iron Seasoning

Use grapeseed oil instead.

Flaxseed oil gets pushed online because it creates a super hard, glass-like polymer coating – sounds great, but in practice that coating tends to chip and flake off after a few uses. Grapeseed oil gives you a durable, flexible seasoning that actually lasts.

Both oils work the same way: thin layer on the pan, bake at 400-450°F for an hour, cool, repeat 3-4 times. The difference is the fat composition. Flaxseed is mostly polyunsaturated (alpha-linolenic acid), which polymerizes aggressively into a brittle film. Grapeseed is polyunsaturated too (linoleic acid), but it forms a tougher, more flexible bond. Plus grapeseed’s smoke point (around 420°F) is easier to hit in a home oven than flaxseed’s (around 225°F – you’re basically just baking the oil, not polymerizing it cleanly).

If you already have flaxseed oil lying around, you can make it work – but keep the coats very thin and expect to reseason sooner. Grapeseed is cheaper, more forgiving, and less likely to make you curse your pan after a fried egg sticks to a flake.

Don’t overthink it – just use grapeseed and cook bacon.