Glossary
Ricing
Small solid clumps that form in soap batter when a fragrance oil reacts badly with the recipe.
Ricing is when small, hard, rice-grain-like lumps suddenly appear throughout soap batter, usually right after a fragrance oil is stirred in. It happens when certain ingredients in the fragrance oil react with the oils or lye in the batter and solidify faster than the rest of the mixture around them.
Some fragrance oils are more prone to causing ricing than others, and the same fragrance can behave differently depending on the recipe's oils, water amount, and temperature. It tends to show up more with recipes that already trace quickly or run on the cooler side when the fragrance is added.
Once ricing starts, it is difficult to fully blend back out, though continued stick blending can sometimes smooth it. A common approach is to test a new fragrance oil in a small batch before committing a full recipe to it, and to add fragrance at a slightly warmer temperature and thinner trace, since both can reduce how sharply a fragrance oil reacts.