1. Sharp knives and wooden utensils
Contrary to what some might believe, placing sharp knives in the dishwasher can quickly dull their blades. The powerful jets of water often cause the blades to bang against other utensils or the dishwasher racks, resulting in nicks and loss of sharpness. Additionally, the intense heat and harsh detergents can damage wooden handles, causing them to crack, warp, or peel away from the blade. This not only shortens the life of your knives but also creates a safety hazard when reaching into the dishwasher.
To maintain your knives and wooden utensils, always wash them by hand using warm, soapy water immediately after use. Dry them thoroughly with a towel to prevent rust, especially if they are made from carbon steel. Store knives in a dedicated knife block or magnetic strip to keep them safe and sharp. For wooden handles, periodically apply food-grade mineral oil to preserve the finish and prevent drying out. Even knives labeled “dishwasher safe” will benefit from hand washing to extend their sharpness and longevity.
2. Refined crystal and fine porcelain
Fine crystal glassware and porcelain require gentle care that dishwashers cannot provide. The high-pressure water jets can cause fragile pieces to collide and chip or break. Harsh detergents and elevated temperatures can permanently damage the surface of crystal, leading to clouding and loss of brilliance over time. Delicate metallic decorations like gold or silver trim are particularly vulnerable and may fade or peel off after repeated dishwasher cycles.
To protect these valuable items, wash them carefully by hand using a mild detergent and lukewarm water. Place a towel inside the sink or a plastic container to cushion them and avoid slipping. After washing, rinse thoroughly and air dry on a rack or dry gently with a soft, lint-free cloth. Avoid stacking heavy objects on top of these delicate pieces to prevent damage.
3. Cast iron pans
Cast iron pans are prized for their durability and natural nonstick properties, but dishwashers are their enemy. The combination of harsh detergents and high heat strips away the seasoning — a polymerized oil layer that protects the pan and prevents rust. Without this protective coating, the pan’s surface becomes prone to rust and degradation, shortening its useful life.
Proper care involves hand washing cast iron with hot water and a stiff brush; soap is generally unnecessary and can remove seasoning. After washing, dry the pan completely by warming it on the stovetop over low heat. To maintain the seasoning, lightly coat the pan with a thin layer of cooking oil while it is still warm. Avoid soaking cast iron pans for prolonged periods to prevent rust formation.
