Leaving your dishes face up on the bottom rack of a dishwasher can affect the cleaning and drying performance, and it is generally not recommended. Here's why:
Water spray coverage: When dishes are face up, the water spray from the dishwasher's rotating arms may not be able to reach all surfaces of the dishes effectively. This can result in less efficient cleaning, leaving food residue and stains behind.
Stagnant water: With the concave side facing up, dishes can collect water, creating puddles where debris can settle. This can lead to a less hygienic wash and can also cause water spots and film on the dishes.
Safety concerns: Sharp utensils or items with pointed edges, like knives or forks, facing upwards can present a safety hazard when unloading the dishwasher. It's safer to place them facing down to avoid accidental cuts or pricks.
Stability: Placing dishes face up may make them less stable during the dishwasher cycle. They might shift or fall over, preventing proper cleaning and possibly causing damage to the items themselves or the dishwasher components.
For optimal dishwasher performance and safety, it is generally recommended to load dishes with the dirty side facing the water spray and the concave side facing down. This allows the water to effectively reach and clean all surfaces of the dishes while also promoting better drying.