Adding the oil at the trace stage also keeps the oil in its natural state, unaffected by
the lye and providing instant nourishment to the skin when used. When adding oil
during the trace stage, use an amount of lye calculated to yield 1% excess fat;
otherwise, the soap will be too oily, because in addition to the oil you add it will have
excess fat from the depleted amount of lye during saponification. Also, when
calculating the amount of lye needed, be sure not to include the oil you plan to add
during trace.
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