Dishwasher Test: To Rinse Or Not?


Do you really need to rinse dishes before putting them in the dishwasher? We at Viewpoints decided to find out for you.

The Viewpoints team made lasagna in the slow cooker and used the dirty dishes to perform the ultimate dishwasher test – to find out once and for all if pre-rinsing dishes really makes a difference in the performance of a dishwasher.

An average household uses 6,000 gallons of water per year rinsing dishes before putting them in the dishwasher. Experts insist that rinsing dishes before loading the dishwasher is an unnecessary step that only wastes water and time. Still, many consumers stand by experiences that indicate failing to rinse dishes beforehand results in an even bigger mess when food particles are left behind.

In the Viewpoints kitchen, we have two dishwashers. What better place for an experiment? We decided to put our Kenmore Elite built-in dishwashers through a side-by-side test after cooking lasagna in both a Hamilton Beach 6-Quart Slow Cooker and a Crock-Pot 5-Quart Manual Slow Cooker to find out what happens when you rinse or don’t rinse your dishes before putting them in the dishwasher.

The test

Kenmore Elite

Kenmore Elite Built-In Dishwasher

Half of the lasagna-covered dishes, including a slow cooker insert and bowls, were scraped of solid food, then they went straight into the dishwasher without rinsing.

After the remaining crock pot and bowls were scraped and rinsed they were loaded into the second dishwasher.

We put the slow cooker inserts on the bottom racks, bowls on both the top and bottom and ran each dishwasher on the normal wash cycle with Cascade Action Pacs with Dawn 4X Concentrated detergent, a new formula that’s already gotten positive reviews on Viewpoints.

The verdict

As expected, all the “pre-rinsed” dishes turned out clean.

Of the “no rinse” dishes, the slow cooker insert and bowls on the bottom rack came clean of baked-on cheese and sauce, although there was some detergent residue left on the crock pot.

But here is most interesting and a bit of a surprise. We saw mixed results from “no rinse” dishes on the top rack. The bowls closest to the back of the dishwasher were clean, but those closer to the front were still dirty. And the bowls that did still have food on them were even harder to rewash because the cheese and sauce had hardened.

How dishwashers work

Dishwashers work by dispensing detergent and water heated to at least 140 degrees onto your dishes, causing food to slide down towards the bottom of the dishwasher. The dirty water is then drained, and dishes are rinsed and often heated to dry.

Our “no rinse” crock pot and bowls on the bottom rack were closer to the water jets and detergent dispenser, which may explain why they came clean even though we didn’t pre-rinse them.  It may be that some of the “no rinse” bowls on the top rack were still covered in food because not enough water and detergent reached the dishes to do the job. We found that when food does not completely wash off it tends to harden onto the dishes as they dry at the end of the cycle, which ultimately makes rewashing more difficult.

How much you use your dishwasher can affect how well it cleans. Along with more wear and tear comes a greater chance it will fail to clean all dishes completely in every load. Our dishwashers at Viewpoints stand up to moderate use with each running about two loads per day.

Dishwasher lesson learned

To optimize cleaning power it’s also important to make sure your dishwasher is loaded properly. A general rule of thumb is to place cups and dishes that only need to be sanitized on the top rack, but that can be difficult when you have a large amount of one kind of dish like we had with bowls. Because cleaning performance depends on how easily water and detergent can reach the dirty part of the dishes, loading your dishwasher as correctly as possible—with the dirtiest dishes on the bottom rack—should improve results. 

Editor’s note: If you have professional experience with dishwashers or slow cookers, Viewpoints is recruiting experts in priority product categories to write for our blog. Check out this overview of the Viewpoints Category Expert Program, including qualifications, compensation and how to apply.

Want more information on choosing the best dishwasher? Visit the Dishwasher homepage 

Michelle Esche Michelle Esche (1 Posts)

Michelle is the Community Manager for Viewpoints.