Why Did My Black Soap Turn Gray?

Short answer: gray instead of black usually means there wasn't enough colorant, it wasn't mixed in well, titanium dioxide got into the black, or the soap didn't gel. A white, chalky film on top is soda ash, which is more obvious on black than on any other color. And black lather or a stained washcloth means the black is bleeding, which black iron oxide does when you use too much. Here's how to sort out which one you've got.

Start with the colorant

Black takes more colorant than most colors, and each type of black behaves a little differently, so start by looking at what you used and how much.

Too little colorant turns black gray

Fresh soap is off-white, which leaves black a lot of light color to cover. Come up short and you get charcoal, slate or medium gray. Use the full recommended amount for your colorant.

Black iron oxide is the deepest black, but it bleeds

Black iron oxide (CI 77499) gives the deepest black, and it's completely stable in soap: no fading, no morphing. The catch is that it bleeds in use. Too much can turn the lather gray or black and stain washcloths and towels, so use only what you need. It's a very fine powder that clumps easily, so mix it with a little water first to avoid specks.

Activated charcoal needs oil and gel for a rich black

Activated charcoal makes a rich, natural black when it's handled right: mix it well into your oils first, before it goes into the batter, then gel the soap. Charcoal that isn't dispersed leaves specks and a grayer bar, and ungelled charcoal soap looks lighter and flatter.

Black micas give a shimmery charcoal-black

Black micas bring sparkle and depth, but they usually cure to a deep charcoal-black rather than an inky jet black. For the darkest result, use black iron oxide, or activated charcoal mixed into oil and gelled.

Pure dyes and lakes don't work in cold process

Black dye is usually a blend of several pure dyes, and pure dyes and lakes can't handle cold process pH. The blend comes apart and the bar ends up purple, green, brown or gray. Water-soluble dyes are fine in melt and pour, where there's no lye. Lakes are oil soluble and don't work in melt and pour either.

Other things that turn black gray

Titanium dioxide makes black gray

Titanium dioxide added to the black lightens it toward charcoal. Don't add it to make black stand out: it fades color. Keep it out of the black portion entirely.

Soda ash leaves a white film on black soap

That powdery white or gray layer on top is soda ash, not a color change. It forms when fresh soap meets air, and nothing shows it off like black. Spritz the top with alcohol after pouring, cover the mold, or keep the soap warm enough to gel. Steaming or planing the top removes ash that's already there.

Skipping gel makes black look lighter and duller

Gelled black is deeper and glossier, especially with activated charcoal. Ungelled black looks lighter, flatter and grayer, and a partial gel leaves a dark center with a grayer outer ring.

Light streaks are glycerin rivers

Pale, veiny streaks running through a dark bar are glycerin rivers. A high water amount and a hot gel are the usual triggers, especially if titanium dioxide is in the mix, and they stand out on black. A little less water helps.

Vanillin can warm black toward brown

Vanillin browns soap over time. It's hard to spot on black, but it can warm a cool black into brownish-black. For a true, cool black, choose a fragrance with no discoloration from our no acceleration, no discoloration fragrance oils.

Clumped colorant leaves specks

Activated charcoal and black iron oxide both clump. Stirred in dry, they leave dark specks while the rest of the bar looks grayer than it should.

What color did it turn?

Charcoal, slate or medium gray all the way through: too little colorant, charcoal that wasn't mixed into oil first, or titanium dioxide in the black.
White or gray film on top only: soda ash.
Lighter, flat gray with a darker center: the soap didn't gel fully.
Shimmery charcoal instead of jet black: a black mica. That's its normal look.
Purple, green or brown cast: a black dye blend breaking down.
Brownish-black over weeks: vanillin.
Light, veiny streaks: glycerin rivers.
Dark specks: charcoal or black iron oxide wasn't dispersed.
Black lather or a stained washcloth: too much colorant, usually black iron oxide.

When did you notice it?

Right away, while pouring or in the mold: too little colorant, or a black dye blend reacting to lye.
When you cut it (1–2 days): soda ash on top, gel and temperature, glycerin rivers, or specks.
During cure (the first few weeks): vanillin warming the black, or soda ash that keeps forming.
When you use it: black lather or stained washcloths from too much black iron oxide.

How to fix it next batch

Get the amount right. Black needs more colorant than most colors, so use the full recommended amount, but don't go over it with black iron oxide or the lather will turn dark.
Match the black to the look. Black iron oxide for the deepest black, activated charcoal for a rich natural black, and a black mica when you want shimmer. Skip pure dyes and lakes.
Disperse each one the right way. Activated charcoal goes into your oils first and gets mixed well. Black iron oxide goes into a little water. Black micas go into a little light oil, about 1 teaspoon to 1 tablespoon, blended until smooth.
Gel it. A full, even gel is what turns activated charcoal a rich black.
No titanium dioxide. Keep it out of the black.
Head off soda ash. Spritz the top with alcohol after pouring and cover the mold.
Trim the water. A little less water helps prevent glycerin rivers.
Do a wash test. Try a new black in a few ounces of batter and lather up a test bar before making a full batch.

Nurture blacks for cold process

These are made and tested to hold their color in cold process:

Black Iron Oxide: our deepest black. Use only as much as you need so it doesn't color the lather, and mix it with a little water before adding it to your batter.
Activated Charcoal: a rich, natural black when it's mixed well into your oils first and the soap is gelled.
Blackout: the deepest black in our mica lineup, with almost no undertone.
Pitch Perfect Black: a rich black softly kissed with silver shimmer.
Into The Void Black: a moody black flecked with red, blue and gold sparkle.

Can't get to black?

Send us a photo of the bar and tell us which black you used, how much, and whether it gelled. We'll help you figure out what's turning it gray. Send it to Color Rescue or email your photos to support@nurturehandmade.com.