Disclaimer: Our Farm and Research Blog has been created to share our research findings and daily farm life with the public. We are not professionals and none of our blog posts represent professional advice. Please consult a professional for individual advice.

How to Make Laundry Soap (part 1 - rebatch/reuse)

Soap making is both a science and art and I am still rather new to the trade. My interest took shape two years ago when I put in some sweat and tears (no blood, thankfully)and learned to milk our goats as we went through our first kidding season. I only milked them for the first few days for their colostrum. All farm babies (all babies really) need colostrum to get a healthy start in life. If there is ever a problem, it is really important to be sure that the babies get colostrum and having frozen on hand is a million times better than store-bought. Once I knew I would want to milk goats in the future, I started to look into the things I could do with it, and making cheese and soap were the two that interested me the most.

I didn't really learn how to make soap until last year. I decided to milk our only doe that kidded, a black and white Boer goat named Lady. I was in school at the time and working on my research and probably stretched a little thin, hence our reasoning for only breeding one doe. I had wanted to learn to make cheese but never got the opportunity and it led to an overabundance of goat milk. I decided then that it was time to learn to make soap. Next time (a.k.a. this year), I also want to learn to make cheese.

Since I took the dive and made my first batch, I like to talk about my new hobby to just about everyone. As more and more people have found out about my interest, I have been asked a few different questions that I often think about. I was recently at a dinner for a friend's graduation and someone asked me about reusing soap bars. They said that they saved the bar ends from their used soap and wanted to make them into a new bar of soap and started asking me questions about it. I explained about rebatching soap, making confetti soap (using pieces of other soap in a new soap) and a little about using soap in laundry soap. I'm not sure if they ever decided what to do with their soap ends.

At the time, I had made one soap rebatch and already turned from that to making laundry soap. A soap rebatch is when a newly made loaf of soap is grated down completely and put into a pot. A little water is added, and it is all melted back down and rebatched into another loaf of soap. When I made it, I literally had to shove the soap-goo-melt into a soap loaf mold and let it set. And then I unmolded it and cut it again. A rebatch is usually done in order to correct a problem that occurred when making the soap, for instance if it was lye-heavy. In my case, I just like to experiment with different techniques and I was unhappy with how the finished soap looked so it was an excuse to try the rebatch. The soap didn't look too bad really, it just looked ugly on top because the sandalwood fragrance I used accelerated my soap batter really fast and I moved too slow. I rebatched it and it ended up looking WAY WORSE, with chunks of soap not totally melted and flecks of paprika that I had thrown in at the last minute to at least change the color, but didn't work.

I suppose the soap's not really that bad. That sandalwood fragrance that I struggled so hard with smells pretty nice. However overall, I don't really care for it. So, even after the rebatch I was looking for another purpose for this soap.

At the same time all this was going on with the sandalwood soap fiasco, I was taking notice of anything soap-like that we were purchasing at the store. I kept thinking about how wasteful it all is. I especially dislike laundry detergent - the HUGE plastic container that I can't think of a way to reuse really irritates me! I kept telling Rich that we need to figure out a different way to do this. I finally realized that my problem in one area could serve as my solution in another. So I started to look online for ways to reuse the sandalwood soap nightmare into some laundry soap.

I found an excellent resource with the Brambleberry Soap Queen's write-up on DIY laundry soap. I have tried a few versions of the three recipes listed in her tutorial. The neat part about this laundry soap DIY is that you can create it depending on your preferences. For instance, the first time that I made the laundry detergent I was really tired of our dingy-clean clothes and so I made a laundry soap mixture that was more like the one listed for heavy duty loads - with washing soda and citric acid. The heavy duty soap worked so well it cleaned our laundry machine and the drainage lines! This stuff was awesome and it got out stains that I didn't think were going anywhere, although it did wear down some of our clothes - as in I found a few holes in sweaters that I had never noticed before. I decided that once I was finished with that batch, I would make a less abrasive detergent.

The second time I made a lighter version of the laundry soap, with borax, baking soda, and much less citric acid, and I still used my own grated soap. This is the soap that we're almost out of right now and I've been quite pleased with this recipe. The only thing that I didn't like was that this recipe solidified into what I refer to as laundry pucks.

I learned that I needed to put those first two recipes into individual molds the hard way - I put the first one all into a large jar with an airtight lid and set it in the laundry room and it all turned to one big brick of laundry detergent! Luckily, I save used egg containers, so those came in handy when I found the laundry detergent brick and needed to quickly break it up to repack it individually. It all worked out because I used those pucks for individual sized loads. I would prefer them not to be solid though, because they scrape when I put them in our detergent dispenser drawer and I think it's a little too much soap to use per load.

I'm pretty sure that I know why they were sticking together - the citric acid in the recipe. I know that this really helps bath bombs to harden up. I also know that I shouldn't work with citric acid when it's humid out or whatever I'm making could be ruined from it soaking up the water in the air. Because of that, I'm blaming the citric acid for now and changing the recipe to see if I can keep this laundry soap in a powdered form for easier storage.

A few notes on this recipe:

First, this recipe is simply a mixture of the DIY laundry soap recipes that I found on the page that I linked earlier. I honestly don't know what outside substitutions might do, so I'm not a good resource for questions there. If you're interested in making your own laundry soap but want to use other ingredients I would suggest starting with a web search combining "DIY Laundry soap" and the name of the ingredient you would like to use for a place to start.

Second, there is the chance that my laundry pucks stuck together due to 1)using fresh soap bars that are less than 6 months old and/or 2) the humidity in my laundry room reacting with a different ingredient. I'm experimenting this time and putting the mixture into egg cartons first to see if it solidifies - if it doesn't, I'll transfer it all into a air-tight jar for better storage.

Third, if you're like me and you want to use washing soda but find that you are almost out (or don't have any at all), don't fret. Especially if you're like me and have a gallon of baking soda on hand. I ran a quick search online and found this article from Wellness Mama. She does a great job of explaining the differences between baking soda and washing soda. Then she tells you how to make baking soda INTO washing soda by creating a simple chemical reaction with heat (baking it at 400° for an hour, stirring occasionally). It's very easy to do, just make sure not to breathe while stirring it or you may have a sneezing fit like I did.

And finally, and maybe the best part is that this recipe reuses and recycles household items. It is *not* less expensive than store-bought detergent, although if I were to buy ingredients in bigger bulk quantities, it might be. It works as a solution to reuse things that we don't have a use for otherwise. It's also a sustainable enough solution that my 13 year old daughter doesn't mind washing her clothes using the laundry soap. It is my opinion that this detergent works better for us than store bought, meaning our clothes are cleaner and softer, too.

Making Laundry Soap

The ingredients I'm using in this recipe are fairly simple. Washing soda, baking soda, borax, and soap. I tried to figure out weights in order to make it more precise but I really think just using standard measuring cups is fine here (I'll include weights though).

You'll also need a bunch of utensils to measure the ingredients, grate the soap, sift the powders, and mix it all together. I wear goggles and a mask when I'm pouring the baking soda, washing soda, and borax because I'm rather sensitive to all those flying in the air. I make sure all of my tools are clean and dry and I wear disposable gloves (I forgot to put them in the picture) throughout making the laundry soap.

The first step to making the laundry soap is to grate up about 5 cups or 16 oz of soap. I suggest wearing disposable gloves and grating it into a large measuring cup. Once the 5 cups of soap are grated, I also suit up the rest of the way.

Then take a large bowl and measure out 2 1/4 cups or 34 oz of washing soda, 2 cups or 18 oz of baking soda, and 1 cup or a little less than 7 oz of Borax. When pouring these into the large bowl, pour them through a sifter to make sure there are no clumps and they can sift together. Once they're all in the bowl, stir it up with a whisk.

Begin to add the soap while still stirring with a whisk but it can be a little difficult to keep the soap from clumping, so switching to hands to mix it up usually happens. Once it's all mixed together, it's ready to use or to store. In this case, I have put all of my laundry soap rebatch into those egg containers so that if it hardened up, I wouldn't have to break apart another brick of soap. I made it yesterday evening and all of it is still in powder form, so I think that it may stay like I want it. I'll transfer it to an airtight jar in a few more days when I'm sure.

This recipe filled 60 egg spaces in these cartons, so it makes over 60 loads. If it stays in powder form and I can transfer it to an airtight jar, I'm actually going to make the loads slightly smaller at about 2 tbsp of laundry soap per load. I also put a few splashes of white vinegar in the rinse compartment of our washing machine because vinegar + baking soda = cleaning magic.

Laundry Soap Rebatch Recipe

5 cups (16 oz.) grated soap (any kind)

2 1/4 cups (34 oz) washing soda

2 cups (18 oz) baking soda

1 cup (6.8 oz) Borax


  1. Wear gloves, goggles, and a mask depending on your sensitivity.

  2. Sift all powdered ingredients (washing soda, baking soda, and Borax) into a large bowl and stir together.

  3. While still stirring, add grated soap. If soap clumps together, use hands to break it apart and mix with the powders.

  4. Store powdered laundry soap in egg cartons or an airtight container. To use, measure 2 tbsp or 1 laundry puck into the laundry machine's detergent dispenser. Add a few splashes of white vinegar to the rinse compartment for softer clothes.

This part 1 blog post explores how we're reusing our soap to make laundry soap for our own household use. In part 2, I'm going to make a laundry soap recipe that I recently found through a social media group I follow (they have given me permission). The laundry soap I'll be making next time is a liquid soap, and it's something we'd like to offer to our customers as a way to create more sustainable change. I'll include more details next time, I'm pretty excited to make it and try it out!

Until then, I hope you enjoyed this post and thanks for reading,


11 views0 comments

Recent Posts

See All