Seaweed soap recipe that makes 5-6 bars using the cold-process method. Ingredients include powdered sea kelp, French green clay, babassu oil, and essential oils. Technical information: 16 oz / 454 g / 1 lb batch -- 6% superfat -- 31.9% lye concentration. This recipe traces very quickly and does not require an immersion blender.
Ensure that your soapmaking station is set up with all of the equipment, materials, and tools you need. Pre-measure each ingredient using a digital scale. Take care to wear gloves when measuring the lye.
Make the Lye Solution
For full information on soap-making safety and equipment please head over here. It’s important to read it before trying to make soap the first time. Put on your rubber gloves and eye protection (goggles) and set yourself up in an area with good ventilation. Under a hob, on the doorstep, or outdoors is perfect. Pour the sodium hydroxide into the water and stir with a stainless steel spoon. Be careful not to breathe in the fumes.
Stir until the lye is completely dissolved and then add the French green clay. Adding the clay to the lye solution disperses it much better than if you add it later in the process. Stir well and leave to cool to 100°F (38°C). I tend to set the jug containing the lye solution in cold water in the sink.
Melt the Solid Oils
In a stainless steel pan, heat the babassu oil and mango butter on very low heat until just liquefied. They’ll melt quicker than you think so don’t be tempted to turn up the heat.
Blend the Powdered Seaweed
Powdered sea kelp is relatively fine but can clump in your bars if you add it direct. To avoid this happening, mix the powdered seaweed with 1 TBSP olive oil reserved from the recipe. Blend until smooth.
Add the Liquid Oils & Seaweed Oil
When the solid oils are melted, take the pan off the heat and pour in the liquid oils and the sea kelp oil. If you pour the liquid oils against a spoon or spatula held just inserted in hot oils, it will help to reduce air bubbles forming in your final bars.
Stir well and keep an eye on the temperature. You want the oils to cool to just above 100°F (38°C).
When cooled, pour in the essential oils and stir well. It's unusual to add essential oils to soap this early, but this recipe traces quickly so you'll be glad for doing it now.
Make Seaweed Soap
Get the mold prepared, along with the chopped rosemary. You will be working quickly from this point.
When the lye solution and oils are both about 100°F (38°C), pour the lye solution into the pan of oils. Again, pour the lye solution against a spoon or other implement to reduce air bubbles.
Gently but quickly, stir the contents of your pan, and do not be tempted to stick blend. This recipe traces quickly and almost immediately after stirring you'll see chunky white blobs in the pan. Keep stirring until the entire pan is a consistent creamy color and has thickened up to the texture of warm custard. This takes less than a minute and you need to work even faster now.
Mold and Cool the Seaweed Soap
Pour the soap into your mold, and I recommend a silicone loaf mold. Create texture on the surface of the soap, decorate with pieces of rosemary, and pop the mold into the refrigerator. Leave it there for 12-24 hours.
Cut and Cure the Seaweed Soap
Take the seaweed soap out of the refrigerator the next day but leave it inside the mold. Set it someplace on the counter and leave it there for another day to harden up a bit. Saying that, this soap hardens up relatively quickly and could be popped out of the mold much earlier. 48 hours is safer though since most of the saponification is complete by then.
Use an ordinary kitchen knife to cut it into bars. Their thickness is up to you. The soap may be yellower than the cured soap after just being cut, and the seaweed pieces won't have had time to infuse a halo of color around them so don't worry if your bars don't look light green right away
After you cut them, leave the bars someplace airy and out of direct sunlight to cure for at least four weeks. For full instructions on how to cure handmade soap, and why a minimum month for curing is important head over here
Using your Homemade Seaweed Soap
The lather and feel of this handmade seaweed soap is fluffy and silky. The scent is a gorgeous herbal blend but you may get the faint smell of sea kelp as you use it. Using more kelp than listed in this recipe will give you darker bars that smell even more like sea kelp.
Once made, your soap will have a shelf-life of up to two years. Check the oil bottles that you're using though -- the closest best-by date is the best-by date of your soap. That's because some of that oil is free-floating in your bars as the superfat, and it can go rancid over time.