Dishwasher safety - "top shelf" vs. "bottom shelf"
The instruction manual for some of my kitchen equipment says "Dishwasher safe (top shelf)".
What difference is there between what an object on the top shelf of a dishwasher experiences, and what happens to an object on the bottom shelf?
What are the risks of putting one of these items on the bottom shelf?
Best Answer
In most dishwashers the heating elements are on the bottom only. Lightweight plastic items might melt (soften and distort, not drip away) on the bottom, but they don't mind being in the steamy environment or being sprayed with hot detergent-laced water. They are therefore only dishwasher safe on the top shelf.
I've melted a plastic bowl or two in my time; there is a definite difference between top and bottom.
Pictures about "Dishwasher safety - "top shelf" vs. "bottom shelf""
Is there a difference between top and bottom rack dishwasher?
Know what the top and bottom racks are for The top rack is also where you should place dishwasher-safe plastics, to prevent them from warping. The bottom rack is for plates and platters and eating utensils (assuming your cutlery basket is on the bottom).Why is the top rack of the dishwasher safe?
If an item is marked "top rack only," it means it's only safe to be washed on the top rack of the dishwasher. The heating element in dishwashers is typically on the bottom of the machine, which means the top rack is comparatively cooler than the bottom.Does it matter what rack you use in the dishwasher?
The lower rack should be used for plates, large bowls, pots, and pans. The upper rack is for glasses, coffee cups and odd-shaped utensils. The silverware rack is for forks, knives, spoons, measuring spoons and small utensils.Why is melamine only top rack dishwasher safe?
Plastic is typically washed on the top rack of the dishwasher because it can melt if it is too close to the heating element on the bottom. However, melamine is durable enough to be washed on the bottom rack of the dishwasher.How to Correctly Load your Dishwasher...
More answers regarding dishwasher safety - "top shelf" vs. "bottom shelf"
Answer 2
Differences include:
- higher heat (water's had a chance to air cool before it gets higher up)
- higher pressure
The pressure isn't as big of a deal typically (it could scrub off some finishes, but generally those items aren't marked as being 'dishwasher safe' at all. But for lighter weight items, it often means that they flip over or get thrown (possibly to the bottom of the dishwasher, where the heaters for drying are).
Answer 3
This only applies to dishwashers with heated dry cycles. However, many brands of dishwashers use condensation drying rather than heated drying, in which case your plastics are safe in the lower rack (example).
Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.
Images: Thirdman, Polina Kovaleva, Thirdman, Anna Tarazevich