Dishwasher Detergent Buying Guide

Imagine a pile of dishes several hours after hosting a houseful of dinner guests, with plates covered in a sticky sauce and pots coated with stuck-on food. Welcome to CR's dishwasher detergent lab. 

To test how well a dishwasher detergent cleans, CR testers load four identical dishwashers with glasses, bowls, and clear glass plates coated with a mix of baked-on foods, and two stainless pots with baked-on mac and cheese. We run the dishwashers using the normal-wash cycle.

When the cycle is complete, testers use a scanner to determine precisely how clean each dish is and inspect each item. We repeat this test two more times. We also examine how well each dishwasher detergent helps dishes resist food deposits, water spots, white film, and discoloration of aluminum. 

Dishwasher Detergent Types

You can choose from three types of dishwasher detergents. Here's a look at each. 

Single-dose units
Also known as pacs, packets, tabs, and tablets, these single-dose units deliver a conveniently pre-measured amount of detergent. This convenience is boosting sales, and CR's latest tests of over 15 detergents found that the best performing single-dose units clean better than the best gels. That's because more and more pacs contain a pretreat solution, degreaser, bleach, or rinse-aid to boost cleaning. Price per load ranges from 10 to 39 cents among the products tested.

This is your least expensive option—the gels we tested cost just 5 to 11 cents a load. Gels can't match the cleaning power of detergent pacs, but two gel detergents we tested do an impressive job cleaning dishes, but have a harder time cleaning pots. And the worst of all 18 detergents we tested is a gel.

You have to measure out the proper amount for each load, of course, and past tests found they can get the job done, although they all had a hard time cleaning pots. Sales are dropping as consumers choose pacs and gels, so CR did not include powder formulas in our latest tests. 

How to Boost Your Dishwasher's Performance

If your dishwasher has a manual-clean filter, it's important to clean it regularly. That's because bits of food end up in the filter, and it's the filter that prevents food from redepositing debris on clean dishes. Here's what else to consider.  

Skip pre-rinsing. Most dishwashers sold in the past eight years or so that cost $500 or more have a sensor that checks how dirty the water is. The sensor determines the amount of water and time needed to get the dishes clean. But if you pre-rinse your dishes and the sensor detects little food, the dishwasher gives the dishes a lighter wash, which can leave bits of food on dishes and glasses. Do scrape off dishes and pots, however, before you load them in the dishwasher. 

Load right. Your owner's manual will recommend a loading method that works best for your dishwasher. In general, you want to load large items along the sides and back so they don't block the water and detergent. Face the dirtier side of dishes toward the center of the machine, and don't let dishes or utensils nest together. Place items with baked-on food in the bottom rack, face down toward the sprays. Rest glasses upside down on prongs so they don't fill with water. Use the top rack for plastic and delicate items that are dishwasher-safe. 

Use a rinse aid. Regardless of which dishwasher detergent you use, if it doesn't contain a rinse aid, consider using one. Rinse aids prevent spotting and improve drying. That's because the rinse aid breaks the bond between the water molecules and dishes, causing water to form sheets and slide off.

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