Using Liquid Dishwasher Detergent? Stop.
You might think that whatever dishwasher detergent you use is inconsequential. All dishwasher detergents are more or less the same, right? Wrong.
As the author of Wirecutter’s dishwasher detergent guide, I’ve learned in testing and reporting that the brand of dishwasher detergent you buy doesn’t matter as much as the form does. And I am sorry to say this, but that jug of liquid dishwasher detergent is the weakest performer compared with powder or powder-based pod dishwasher detergents.
In my multiple years of researching, testing, reporting, and writing about dishwashers and their detergents, I’ve heard a lot of opinions from dishwasher experts — sometimes even conflicting ones.
But there is one thing that every dishwasher expert agrees upon.
Powder dishwasher detergents or powder-based dishwasher detergents, such as our top pick, Cascade Free & Clear ActionPacs, are superior cleaners to liquid gel dishwasher detergents.
Top pick
There’s a scientific explanation for this. In addition to your traditional surfactants (soap-like molecules that help clean crud from pots and pans), dishwasher detergents often contain enzymes and bleaches. These are some of the most integral ingredients in the most effective dishwasher detergents.
Enzymes are biological molecules that are prevalent in the environment and even in the human body. One function of enzymes in the body is to help break down fats and starches in the digestive system. In dishwasher detergent, enzymes incite chemical reactions that make it easier for food soils to be broken down. The enzymes clear the way for other agents, such as surfactants and stain-removing bleaches, to do their job.
Runner-up
The problem is that enzymes and bleach don’t mix well. Enzymes are sensitive little buggers that thrive in mild environments. And when liquid enzymes and liquid bleaches are combined, the enzymes are weakened, and eventually their cleaning power is lost. That’s true even though manufacturers have developed hardier enzymes in recent years.
Powder and pod vs. liquid detergent
Therein lies the weakness of liquid detergent: You can’t combine the two ingredients in liquid form without degrading the enzymes. Because of that problem, liquid dishwasher detergents tend to come in two types: with bleach or with enzymes. Either version can clean your dishes, but not as well as a powder or powder-based pod with both bleach and enzymes.
In my testing, liquid gel dishwasher detergents barely made a dent in proteins such as egg and cheese. That makes sense: Without enzymes to help, the other cleaning agents struggle with those tough soils. And without bleaches, the enzymes begin the work, but there aren’t any powerful cleaning agents to finish the job as thoroughly.
I’ve found that to be true even when testing the powder version of a detergent against the same brand’s liquid counterpart. Low-performing, generic-brand powder dishwasher detergents that ranked among the weakest cleaners in my dishwasher testing still had better scores than gel detergents. This was the case across the board, even when it seemed like some powder dishwasher detergents could not be worse.
There’s a reason for this: Bleaches can coexist with enzymes in powder form without destroying or deactivating the enzymes’ cleaning properties. “Bleach and enzymes are more stable in powder form because they’re in a dry state, which minimizes the potential for chemical reactions and interaction,” explained Morgan Eberhard, a senior communications scientist for Cascade dishwasher detergents, in a written interview. She added that because powder detergent slowly dissolves, bleach’s potential for deactivating the power of enzymes is much lower.
Enzymes also break down soils early in a dishwasher cycle, before bleaches, surfactants, and other cleaning agents get to work. That allows the two powerful cleaning agents, enzymes and bleaches, to work in tandem, and that one-two punch is the most powerful cleaning option when it comes to dishwasher detergents.
Best for…
Nearly all currently available dishwasher detergent pods contain powder dishwasher detergent, though our top pick, Cascade Free and Clear ActionPacs, takes the idea one step further. Thanks to the pods’ synthetic polymer polyvinyl alcohol (PVA/PVOH) casing, they contain both powder and liquid cleaning agents and even include a fast-acting liquid enzyme. The liquid top eventually combines with the powder base to deliver more soil-busting cleaning power than a powder dishwasher detergent achieves alone.
