Can you put cast iron in the dishwasher?

The non-stick surface of a cast iron pan is polymerised oil bonded to the metal, built up over many uses. Dishwasher detergent is strongly alkaline and specifically formulated to break down fats and oils, so it dissolves exactly that layer. Underneath is bare iron, and the long wet cycle plus the heated dry leaves it to oxidise — pans routinely come out orange. Cast iron should be washed by hand, dried immediately on the hob, and wiped with a thin film of oil.

What goes wrong

• Detergent strips seasoning built up over months of use.
• Bare iron rusts within hours of a wet cycle.

What to do instead

• Wash by hand with hot water and a stiff brush; a little mild soap is fine.
• For stuck-on food, simmer water in the pan and scrape, or scour with coarse salt.
• Dry on a warm hob, then rub in a thin coat of neutral oil.

Other "can you dishwasher" questions

• Can you put knives in the dishwasher? No — No, if you care about the edge. Heat, detergent and knocking all dull and damage it.
• Can you put non-stick pans in the dishwasher? It depends — Only if the maker says so, and it still shortens the coating life considerably.
• Can you put an insulated bottle in the dishwasher? It depends — Only if it says dishwasher safe. Older vacuum flasks can lose their vacuum and stop insulating.
• Can you put wooden spoons in the dishwasher? No — No. Prolonged soaking and heat raise the grain, then crack and split the wood.