You should not wash good knives in the dishwasher. The high heat, harsh detergents, and banging against other items will dull blades, warp handles, and loosen rivets. If you must use the dishwasher, only cheap stainless steel knives with full-tang, riveted handles are safe, and even then you need to follow strict steps to minimize damage.
Will the dishwasher ruin my knives? Yes, it will dull blades faster, corrode some steels, and damage handles. Can any knives go in the dishwasher? Only full-tang, riveted-handle stainless steel knives with no wooden or hollow handles. What about ceramic knives? Never—they can chip from impact. How should I load them? Place knives flat on the top rack, pointed down, separate from other utensils. Best practice? Hand wash with mild soap, dry immediately.
- Heat Damage: Dishwasher water reaches 140-160°F, which can warp thin blades and soften epoxy in handles.
- Detergent Impact: High-alkaline dishwasher detergents can pit stainless steel and corrode carbon steel.
- Physical Impact: Knives banging against racks and other items creates micro-chips and dulls the edge.
- Handle Deterioration: Wooden handles crack, plastic handles discolor, and rivets loosen over repeated washes.
Why the Dishwasher Is Bad for Most Knives
The dishwasher creates a harsh environment for knives. The combination of high heat (140-160°F), strong alkaline detergents, and mechanical jostling accelerates blade dulling and handle damage. Even high-carbon stainless steel, common in premium knives like Wusthof or Zwilling, can develop micro-pitting from detergent residues. Wooden handles absorb water and crack; plastic handles become brittle and fade. The blade edge can also be blunted by contact with racks, other utensils, or the spray arm.
For knives with hollow handles (often found in cheaper sets), the dishwasher can cause water to seep inside, leading to rust and corrosion from the inside out. Full-tang knives with riveted handles are more durable, but the repeated thermal cycling still stresses the metal and handle materials. In short, the dishwasher is the fastest way to ruin a quality knife.
Which Knives (If Any) Can Go in the Dishwasher?
If you decide to risk the dishwasher, only certain knives are suitable. Look for knives that are:
- Stainless steel – not carbon steel, which rusts easily. Check for “stainless” or “X50CrMoV15” markings.
- Full-tang – the metal runs the entire length of the handle, visible at the butt.
- Riveted handle – handles held by metal rivets, not glued or pressed.
- No wooden or hollow handles – wood will crack; hollow handles trap water.
Examples include inexpensive stamped knives like those from Victorinox Fibrox (though even they recommend hand washing). High-end knives like Shun or Miyabi should never see a dishwasher. When in doubt, hand wash.
How to Prepare Knives for the Dishwasher
- Rinse immediately after use to remove acidic foods that can stain the blade.
- Place each knife flat on the top rack (not in the utensil basket). The top rack is farther from the heating element, reducing heat exposure.
- Point blades downward to avoid injury when unloading.
- Separate knives so they do not touch each other or other metal items. Use silicone knife guards if available.
- Run a normal cycle – avoid “heated dry” or “sanitize” cycles which add extra heat. Open the door immediately after the cycle ends to let steam escape.
Loading and Unloading Best Practices
Loading: Always use the top rack. Never put knives in the silverware basket – they will bang against forks and spoons. If your dishwasher has a dedicated knife slot holder, use it. For long blades like a chef’s knife, lay them flat along the back of the top rack, blade facing away from the center.
Unloading: Once the cycle finishes, immediately remove the knives. Do not let them sit in the humid environment. Dry each knife thoroughly with a soft cloth – do not air dry, as water spots and potential rust can form. Check the blade edge for any chips or dullness; you may need to hone or sharpen after each dishwasher wash.
A Better Alternative: Hand Washing Your Knives
For best knife longevity, hand washing is the only safe method. Fill a sink with warm water and a few drops of mild dish soap. Wash each knife individually with a soft sponge, wiping from spine to edge (never across the edge). Rinse immediately with warm water and dry with a clean towel before putting away.
Do not let knives soak in the sink – it’s dangerous and can damage handles. Store them in a knife block, magnetic strip, or blade guards. With proper hand care, a good knife can last a lifetime. The few minutes you save by using the dishwasher are not worth the cost of replacing dull or damaged knives.
Pro Tips
- Use a silicone blade guard when placing knives in the dishwasher; it prevents edge contact with other items and reduces dulling.
- After a dishwasher cycle, immediately dry knives with a microfiber cloth to prevent water spots and potential rust on the blade.
- If you must wash knives in the dishwasher often, choose a model with a dedicated knife rack on the top shelf to minimize movement.
- Hone your knife with a steel after each dishwasher wash to realign the edge that may have been slightly bent by the process.
Common Mistakes to Avoid
- Putting knives in the silverware basket – they clatter against other utensils, causing chips and dulling.
- Using the heated dry cycle – the extra heat can warp blades and damage handle materials.
- Leaving knives in the dishwasher overnight – humidity and trapped moisture promote rust and handle deterioration.
- Assuming all ‘stainless steel’ knives are dishwasher safe – many high-end stainless steels are still vulnerable to pitting from detergents.
FAQ
Can I put ceramic knives in the dishwasher?
No. Ceramic knives are brittle and can chip or break from contact with other items. They also can become dull from the heat and detergent. Always hand wash ceramic knives with care.
What about my expensive Wusthof or Zwilling knife?
Even though these brands sometimes market knives as ‘dishwasher safe’, most experts advise against it. The repeated heat and chemicals will dull the edge faster and may discolor the blade. Hand wash to preserve the investment.
How can I tell if a knife is dishwasher safe?
Look for a label on the knife or packaging that explicitly says ‘dishwasher safe’. But be skeptical: many manufacturers include that disclaimer only to avoid liability. A better indicator is a full-tang, riveted handle and a blade made of low-carbon stainless steel. When in doubt, hand wash.
The Bottom Line
The dishwasher is convenient, but for your knives it’s a shortcut to dullness and damage. Hand washing takes only a minute and keeps your blades sharp and handles intact. If you absolutely must use the dishwasher, follow the loading and unloading tips above to minimize harm. But for the best performance and longest life, stick to warm, soapy water and a soft cloth.
