Adding fragrance and color

Two additions at the end of the batch, and the ones most likely to end the batch.

At the right point

Color usually goes in before or at emulsion, so it has time to disperse.

Fragrance usually goes in at light trace, near the end, because many fragrances accelerate and adding them early removes the working time.

Both should be pre-dispersed: color in oil or glycerine, fragrance measured and ready in its own container before the lye meets the oils.

Nothing should be being weighed once the batch is moving.

Fragrance

By weight, as a percentage of the oils, at the supplier's recommended rate.

Stir in by hand rather than with the blender where the fragrance is known to accelerate, because the blender will take it to thick trace in seconds.

And expect discoloration from anything containing vanillin, which browns over days or weeks and which you should plan the design around rather than be surprised by.

Color

Dispersed in a light oil, a teaspoon or so per teaspoon of pigment, blended smooth before it goes near the batch.

Split the batch into portions for a multi-color design, and split before adding fragrance if the fragrance accelerates, because you will not have time afterwards.

Judge color on a set, cured bar rather than in the pot: soap lightens as it dries and gel deepens it, so what you see in the container is not what you will get.

What to do when it accelerates

It will happen, and usually on the batch you had a plan for.

Stop blending, switch to a spatula, and abandon the design: get it into the mold while it still moves.

A plain bar is a bar. A seized batch in a bucket is not.

Then record what the fragrance did, so the next batch with it is planned as a plain pour.

References