How To Make A Pencil Line In Soap

This week’s challenge: the pencil line!  This soap features the bottom portion colored with a blend of black, blue, white, and green oxides. The pencil line is made of ground coffee and the top layer has Calendula petals blended in.

So what is a pencil line and how do you do it? The pencil line is a horizontal line that runs through the soap. It’s made by sprinkling a colorant such as charcoal, mica, or cocoa powder over a layer of soap and then adding another layer on top. The trick is to not get too heavy-handed or the soap layers won’t adhere to each other and will separate.

It’s a simple way to incorporate a bit of artistry into soap. Pencil lines aren’t always straight – I’ve seen subtle straight lines as well as jagged ones, but they are all beautiful. It’s really amazing to see how creative soapers get!

Ready to try the pencil line? Below are steps to making a simple line.

Pencil Line

Additional Soaping Supplies: 
Sieve and line colorant (charcoal, cocoa powder, mica, etc.)

Use a recipe and fragrance oil that won’t accelerate trace.
I used oxides to color half of my soap, but it took a little longer to dust on the line than expected. Adding a pencil line to an uncolored batch of soap may be easier for your first try.


  1. Use a kitchen tool that can dust the powder onto the soap like a tea infuser or sieve. The colorant you choose needs to be fine enough to pass through it. Fill the strainer with a teaspoon or so of colorant and set aside. Keep the colorant close by in case you need more.
  2. Bring soap to a light trace and pour one portion of your soap into the mold. I poured in 2/3 because I wanted the line towards the top. Remove any air bubbles by banging the mold on the counter a couple of times.
  3. Gently tap on the strainer to dust the colorant over the entire soap. Do this evenly making sure to just cover the soap. Remember, if the line is too thick the soap won’t adhere.

    A tea infuser works great for dusting colorant onto soap ($1.99 at Ikea).

    A tea infuser works great for dusting colorant onto soap ($1.99 at Ikea).

  4. Clean all colorant from inside the mold so that it won’t speckle the sides of the soap.

    Almost time to pour the top layer!

  5. Layer the rest of the soap on top of the line. Do this slowly and close to the soap so that it doesn’t break through the line.

    Unfortunately my soap thickened up because I took too long creating the line.

    Unfortunately my soap thickened up because I took too long creating the line.

  6. Once you’ve finished adding the rest of your soap, give the mold a few bangs on the counter to get any air bubbles out of the top soap layer. Then texture or decorate the top however you like.
  7. After unmolding the soap, turn it on its side and cut it. This will keep the line from dragging through the entire soap and leaving residue behind.

This was my first attempt at the pencil line and I give myself a B-. The line wasn’t as clean as I wanted and bled a little, so I’m eager to try mica next time. With some more practice I can get this pencil line sharp. Overall I really liked how it turned out! It definitely makes the soap a bit more interesting.

Have you tried the pencil line? What is your favorite colorant to use?