I wrote about homemade laundry detergent several years ago (here). Later, I edited that post to add notes about making a concentrate. I’d grown tired of taking up so much space with my homemade laundry detergent. I wanted to simplify–but still make a lot of laundry soap at once because who wants to make it every week? The trick to a concentrate is the amount of water. Too little water, and the mixture becomes difficult to deal with. Too much water, and you’re back to the storage issue. I’ve tried less water and more water, and since the original post is so old and outdated, I want to share my current method. I’m using a little more water now than I did when I first started making a concentrate, but I think it works better this way–and still doesn’t take up too much space.

Another choice for tighter storage would be a dry mixture–just mix everything up and add it dry to your washer. I’ve never been a fan of dry laundry detergent, though. Especially when washing cold loads, it doesn’t always dissolve.

For the soap in this recipe, you want a super-sudsing and hard grating bar. Fels-Naptha brand is popular for homemade laundry detergent, but for a homemade soap, I have a recipe here: Homemade Laundry Bar. I’ve also used Ivory soap in the past. This time, I was out of laundry detergent and didn’t have any homemade laundry bar soap made, but I had some Fels-Naptha on hand. I used two bars. (The bars are about 5 1/2 ounces each.)

How to make Homemade Laundry Soap Concentrate

2 bars (approximately 4-5 ounces each) plain soap
2 quarts water
2 cups Borax
1 cup baking soda
1 cup washing soda

Grate the soap. I use the grater blade in my food processor.

Bring 2 quarts of water to a simmer. Add the grated soap and stir until melted.

Don’t walk away while you’re melting the soap or you’ll end up with a really clean kitchen, if you know what I mean.

Not that I’ve ever done that. (Uhh….) Stay tuned to your pot and stir it down if it starts to bubble up. (Lower the heat if it’s bubbling up. I also recommend using a big pot.)

Once the soap is melted, turn off the heat and add the Borax, baking soda, and washing soda. Stir to dissolve. The heat of the warm pot will be enough to let it dissolve in a few minutes. Don’t add clumps–Borax, baking soda, and washing soda all tend to clump up in the box sometimes. There’s nothing wrong with it, but it doesn’t dissolve easily so break up any clumps before adding to the pot.

This is the time to add fragrance, if you intend to do so. You can add 10-15 drops of essential or fragrance oil. (Usually, I don’t.)

Cool the mixture. As it cools, it will congeal. Stir to break it up. It will be sort of like mashed potatoes. Transfer to a container. I use an old ice cream container. It fits easily with room to spare so I can keep my measuring cup sticking up out of it.

One of the other things I don’t like about liquid homemade laundry detergent is that it always separates. You have to stir the soap mass back into the liquid. This method avoids that problem. It’s thick enough that it congeals to a soft mass that can’t separate. (Be sure to stir as it’s cooling to keep the mixture balanced as it forms the mass.) There’s enough liquid in it to keep it from getting hard, but not enough to allow it to separate. Store-bought liquid detergents use emulsifiers, by the way. I’ve thought about experimenting with Polysorbate 20 in homemade liquid detergent, but that would still leave the storage issue of making a full-on liquid, so I headed in the direction of finding a concentrate that I liked instead. (I also didn’t like the added cost of using emulsifier in the mixture.)

For this concentrate, use 1/8 to 1/4 cup, depending on the load. If I’m not using hot water for a load, I find it works better to put the amount of the detergent mixture that I’m planning to use in a microwave-safe bowl and heat it in the microwave for 20 seconds to re-dissolve the mixture before adding to the wash.

This makes about 9-10 cups of laundry concentrate, which is 40 loads at 1/4 cup per load or 80 loads at 1/8 cup per load–and only a few cents each time. And it doesn’t take up too much space!