by exmadscientist | 2025-11-07 23:23:55+00:00
What a strange response. While I agree that Alec's test at Technology Connections has a lot of issues, so does this article. There's a lot in here that's right, but also a lot of nonsense, even self-contradictory nonsense.

> If it is not obvious yet, I love detergents. So it is with a heavy heart that I say that dishwasher detergents are, in general, massively overrated. Other aspects of cleaning dominate the role of detergents, particularly in softer water or when using a rinse aid. ... In most cases, however, detergent only plays a minor role [... long snip...] detergents do not make that much of a difference. ... it is extremely important to keep in mind that nothing detergent-related matters that much.

While it is true that there are many effective detergents on the market, there's a simple test that you can do to show yourself that detergent matters a lot. The absolute best detergent I know of available, at any price, is Tergajet. Tergajet is a laboratory detergent that happens to work in household dishwashers. Tergajet is expensive. Tergajet is powerful. Run your dishwasher just once with Tergajet and you'll be able to tell the difference. (The inside of my dishwasher practically sparkles.) Because it is so expensive, I only use it when I have something seriously nasty to deal with (usually when I've inconvenienced/committed minor atrocities against a skillet). It works. And that's prima facie evidence that detergent does matter: if you can see significantly different results by changing it, it's important!

There's almost no discussion of enzyme action and how it's affected by temperature -- this is really important! Enzymes hate heat. The proteases in Tergajet denature above 55°C, so they like to be just below that temperature, while everything else cleans better above that temperature. It is a delicate balancing act. This, incidentally, is what's been going on with Energy Star and detergents. Old dishwashers ran hot (very inefficiently) and cleaned well. Then we lowered the temperature, but didn't reformulate the detergents, and got poor results. Now enzyme-based detergents do a good job at lower temperatures, but need longer to work, as enzymes aren't terribly fast. This has major implications on what you want your pre-rinse to look like, if you're using detergent in it.

> This risk of “saturation” is almost non-existent. First, you only need a few grams of a good surfactant to strip a lot of oil. Second, the pre-rinse and/or pre-wash cycles, even without detergents, will still remove a lot of soil. Your dishwasher’s wash water will be hot enough to loosen oils, further diluting soils during regular cycles. And then your rinse aid will act as a fairly potent degreaser, finishing the (in all likelihood, already finished) job.

> For all practical purposes, to premium dishwasher detergents, a really dirty set of dishes and a moderately dirty set of dishes aren’t all that different, and so it doesn’t make a difference whether only 30% of the soil or a full 90% of the soil was removed during the pre-wash stage. The main wash stage will do just as good a job regardless.

This is absolutely, completely opposite to my results using dishwashers. You want the detergent to be present in excess: the limiting reagent has to be the soil for good results. I dump lots of Tergajet in there if I'm going to the trouble of using any at all. The final rinse cycle will get rid of whatever's left behind (because Tergajet is free-rinsing). Yeah, the pre-wash is great and needs to be powerful, but you cannot skimp on the soap.

Getting in to the detailed formula comparison, I'm struck by how he thinks EcoGeek/Green Llama has to be heavily caustic given that it contains multiple species of citrate pH adjuster. It's probably not all that alkaline. (I don't have any to check, myself. Does anyone know the pH? Tergajet is around 11 or so, which is pretty serious.) He also seems to think that corrosion inhibition is for "longer-lasting dishes and cutlery". Dishes and cutlery (porcelain and stainless) don't care about pH all that much. Corrosion inhibition is mostly about aluminum. If you never put aluminum things in your dishwasher, even by accident, you wouldn't really have to care much about this at all.

Two detergents have "Better performance on soils that benefit from oxidation because of the transitional metal bleach catalyst." ... but the other has TAED, a "bleach activator". Same thing! Yes, they'll have different effectivenesses, but it's disingenuous to say one detergent has this and the other doesn't.

Is any of this fatal to his arguments? No. But they're sloppily argued. I don't think either he or Alec have made solid cases here.