Instructions on how to use parsley to naturally color handmade soap green. This is a re-batch recipe using cold-process soap. You could use any other type of bar soap to recreate it though.
Prepare your soap mold. I'm using a take-away container like you'd get from a Chinese restaurant. It's lined with baking paper, shiny side up. You could also use silicone molds.
Finely pulse or chop the parsley, place it in a pan with the water, and bring to a simmer. Allow to cook for about a minute before taking it off the heat. Pulse the parsley-water with a stick (immersion) blender until you have a fine texture. It's my theory that it's the bits of parsley rather than the juice that ultimately tint the soap.
Shred the bars of soap using a cheese grater. It may take some effort if the soap is fully cured.
Place the shredded soap in the slow cooker and pour the parsley-water over it. Turn the heat on to high and gently stir every five minutes. I also gently squished the pieces to try to break them up a little. Try not to agitate the soap because you want to avoid it becoming sudsy.
After about 30-45 minutes your mixture should look like this. Scoop it out of the slow cooker and press it into molds. It's quite thick so you may need to squish it in.
Allow to fully cool, which can take 12 hours or overnight.
Cut into bars and cure for 2-3 weeks before using. Curing involves spacing the bars out in an airy place and allowing the water to evaporate out. During this time the green may fade a bit. The best-by date of your soap will be the original best-by date of the soap or one year. Whichever is closer. Store this soap in a dim or dark place if possible, the color might not hold up well if left in the light.