Putting knives in the dishwasher can dull them due to a combination of factors:
High water pressure and temperature: Dishwashers use high-pressure water and hot temperatures to clean dishes. This forceful water can cause the knives to knock against other items or the dishwasher's metal racks, leading to chipping and blunting of the blade's edge.
Harsh detergents: Dishwasher detergents often contain abrasive chemicals to remove stubborn stains and food residues from dishes. These chemicals can be damaging to the sharp edge of the knife, wearing it down over time.
Proximity to other items: Knives placed in the dishwasher may come into contact with other dishes, cutlery, or hard surfaces during the washing cycle. This contact can cause the blade to become dull or even sustain nicks and dents.
Long exposure to moisture: Extended exposure to water can cause the knife's metal to corrode and degrade, affecting its sharpness.
To maintain the sharpness and longevity of your knives, it's generally best to wash them by hand with mild dish soap and warm water. Avoid using harsh scrubbers or abrasive materials that could damage the blade. Additionally, make sure to dry the knives thoroughly immediately after washing to prevent corrosion. If you prefer to use a dishwasher for convenience, consider placing the knives in a separate utensil basket, away from other items, and use a gentle or delicate cycle if available. Nevertheless, handwashing is the safest method to preserve the quality and sharpness of your knives.