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Episode 2: Test Details

Want to know more about how we did our tests? Well want no longer!

We bought the cheapest front loading washing machine that we could find at a nearby appliance store and used it for all of our tests.

We primed the water lines with the desired water temperature, so that the washing machine would be using that temperature immediately.

To get the 40 degree mark, we used a large (clean!) garbage container that we filled up with ice and water. To get it below 40, we had to add dry ice, which helped us get it down to 36 degrees (and had the added effect of making the water bubble and producing an evil-scientist-like fog over our testing rig).

To get the cooled water into the washer, we used a little transfer pump to move it from the cold water container. (Our little pump wasn’t built for the kind of stress that we put it under, so it gave up and had to be replaced before the final load.)

We washed 5 loads of laundry (one at each temperature level) containing our test stain samples and enough pre-washed towels to make a regular sized load.

We ran loads at the following temperatures:

• 140 degrees, which is what many water heaters are set at by default
• 120 degrees, which is what PGE recommends that you set your water heaters to in order to both save energy and reduce the chance of scalding
• 70 degrees, which is what the “cold” water in your house might be in the summer
• 40 degrees, which is what the cold water in your house might be in the winter
• 36 degrees, which was as cold as we were able to make the water go (let us know if you have ideas on how we could have gotten the water colder)

We used white cotton napkins for our test stains, and washed them once before staining them to make sure that they didn’t have any kind of extra “stain resistance” from the factory.

For each load, we stained 5 napkins, and left 1 unstained (to see if any stains moved around in the wash - none did). In each load we had the following stains:

1. Protein stains, which we used chocolate pudding to represent
2. Tannin stains, which we used wine to represent (a lovely Oregon Pinot Noir)
3. Oil and fat stains, which we used corn oil for
4. Dye stains, which we used grape instant drink mix for
5. A combination stain that had all four of the above in it

We let all stains air dry on a rack for 2 hours before doing anything with them.

To give all the stains the best chance of getting clean, we used the detergent manufacturer’s instructions for pretreating the kinds of stains that we had, soaking some stains in a solution of water and detergent, and putting detergent directly on other stains and letting it sit for a while. Each set of stains got the same treatment.

We always ran the “rinse” cycle in cold (and you should too). For the warmest three tests, we used the regular “cold” water from the wall for the rinse cycle. For the other two tests we used our ice water.

Each stain sample was marked with a letter to represent the kind of stain that it was (e.g. “O” for oil), and a random three digit number to disguise which load a napkin came from.

We had three people work together to sort each stain type from cleanest to least clean (and we threw in a napkin that had never been stained, and one that was stained but not cleaned for good measure), and asked them to let us know the last napkin that they would consider totally clean. Everything was totally clean except for the specific stains that we pointed out in the video.