Plastic food-storage containers are less likely to warp when washed on the top rack with a cycle that stays at or below 50–60°C / 120–140°F. Proximity to the bottom heating element and high drying-cycle temperatures are the two main causes of warping.
Why Use the Top Rack? A dishwasher's heating element is usually at the bottom. Items near the bottom rack are exposed to more heat during washing and drying. The top rack is farther from the heating element, making it a safer position for plastic containers.
Why Can the Drying Cycle Be Risky? Wash water usually stays below 50–60°C / 120–140°F, but a steam-drying cycle can raise the dishwasher's internal temperature above 70°C / 160°F. This may warp or ripple the edges of thin-walled plastic containers. Turn off the drying cycle and leave the door open so the containers can air-dry.
Is Every Plastic Container Dishwasher-Safe? A basket-and-waves symbol on the bottom indicates that a container is suitable for the dishwasher; if it has no such symbol, hand-wash it in warm water. Older, thin-walled, or inexpensive containers may become cloudy and brittle over repeated high-temperature washes, even if they carry the symbol.
Do Lids and Container Bodies Respond Differently? Lids are often made of thinner, more flexible plastic and may be more sensitive to heat. Place gasketed lids in the coolest corner of the top rack whenever possible. If a gasket hardens and loses flexibility, the container may no longer seal properly.
Why Can Dishwasher Washing Remove Stains More Easily? Hot water and detergent can remove stains from colorful liquids such as tomato sauce more easily than hand-washing, but the heat also increases the risk of warping. For a heavily stained container, use the top rack and no drying cycle.
Does Detergent Choice Matter? Abrasive granules in tablet or powder detergents can leave fine scratches on plastic over time; use a nonabrasive liquid detergent for plastic containers because scratches may harbor bacteria. Adding a little vinegar to the dishwasher's rinse-aid compartment may help reduce mineral buildup on plastic.
For a new container, try a low-temperature cycle during the first few washes and observe how it responds. If the bottom has only a general durability symbol, test the container on the top rack at a low temperature first; if it comes out without warping, use the same setting again. This test helps establish a suitable washing routine without guessing.
Comments (2)
Yıllardır tüm plastik kutuları körü körüne alt rafa atıyordum, birkaçının kenarı hafif eğrilmiş ama fark etmemiştim; şimdi üst rafa geçtim, en azından yenileri düzgün kalıyor.
Plastik kutuyu alt rafa koyup kurutma programını da açık bıraktım, çıkardığımda kapak kenarları dalgalanmış ve artık tam oturmuyor; yazıyı önce okusaydım bu hatayı yapmazdım herhalde.
Alt raf ve kurutma programı birlikte en riskli kombinasyon; bir dahaki sefere üst rafa koyup kurutmayı kapatın, kapağı da mümkünse kapıyı açık bırakıp havada kurutun, deformasyon büyük ölçüde önlenir.