If you’re anything like me, you likely value the convenience of having a dishwasher. It is a marvel of modern technology that saves time and energy after a long day. However, there is a downside: not everything is dishwasher-safe. Putting the wrong items in carries the risk of not only ruining your favorite dinnerware but also damaging the appliance itself, leaving behind sticky residue, and drastically shortening the lifespan of your kitchen tools.
The goal here isn't to cause panic, but to lay out the facts clearly. By understanding what scientists and culinary experts say about safe dishwasher use, you can protect your investments and keep your kitchenware in top condition for years to come. Let’s look at which items shouldn't go in the dishwasher and how to properly care for those delicate pieces.
The golden rule: when in doubt, always check the manufacturer's label. If it says "hand wash only," follow that instruction. The intense heat and high water pressure inside a dishwasher are far harsher than a gentle hand wash.
1. Sharp knives and wooden kitchen utensils
Let’s start with something quite surprising. I recently saw a photo posted on Instagram by famous chef Ina Garten, and—guess what?—there were knives in her dishwasher. You might be wondering, "What’s the problem?"
In reality, the high water pressure causes knives to bang against other objects in the rack, which quickly dulls the blade's edge. Furthermore, high temperatures and harsh detergents can cause wooden handles to crack, warp, or separate from the blade. Finally, reaching blindly into a dishwasher filled with hidden, sharp blades poses a real safety risk.
How to care for them: wash knives and wooden utensils by hand immediately after use, using warm water and dish soap. Dry them immediately with a cloth to prevent rusting (especially with carbon steel) and store them safely in a knife block or on a magnetic strip. Occasionally, apply food-grade mineral oil to wooden handles to keep the wood in good condition. Even if a knife is labeled "dishwasher safe," washing it by hand will help it retain its edge for much longer.
2. Delicate crystal and fine china
If you own high-quality crystal glasses or ultra-fine china, they deserve first-class treatment. High-pressure water jets can cause fragile glass to chip or break upon contact with other tableware. Harsh detergents and high temperatures can permanently corrode the crystal's surface, leaving it cloudy no matter how much you polish it. Additionally, delicate gold or silver decorations risk tarnishing, flaking off, or wearing away completely. How to care for them: Line a plastic basin with a towel to prevent the dishes from sliding, and wash these delicate items by hand using mild detergent and warm water. Rinse thoroughly and let them air-dry on a rack or dry them carefully with a lint-free cloth. Never stack heavy objects on top of delicate tableware.
3. Cast iron cookware
Cast iron skillets are the undisputed queens of the kitchen, but they hate the dishwasher.
Harsh detergents and high temperatures completely strip away the layer of polymerized oil (known as "seasoning") that gives cast iron its natural non-stick properties. Without this protective barrier, cast iron rusts quickly when exposed to moisture and air. Over time, regular dishwasher use will severely damage the cookware's surface. Care instructions: Wash by hand using hot water and a stiff-bristled brush (detergent is rarely needed). After washing, thoroughly dry the pan over low heat on the stove and lightly rub it with oil to maintain its non-stick properties. Never soak cast iron cookware for extended periods.
4. Non-stick pans and pots
It may seem counterintuitive—since non-stick pans are designed for easy cleaning—but they should not be put in the dishwasher.
Harsh detergents and high temperatures damage the non-stick coating (such as PTFE or Teflon), causing it to flake off and lose its effectiveness. This accelerates wear and tear, forcing you to replace expensive cookware much sooner than expected.
Care instructions: Wash by hand using a soft sponge and mild dish soap. Avoid abrasive scrubbers, such as steel wool. Always allow the pan to cool completely before washing to prevent warping. Although some newer-generation ceramic-coated pans claim to be dishwasher-safe...
