A handmade olive oil soap scented with lavender, from Daki, a small Portuguese artisan soap works.
Why olive oil, and why handmade
Soap is made by saponification: an oil reacts with an alkali and becomes soap plus glycerine. The reaction completes in the finished bar, so no lye remains.
What matters is the glycerine. Industrial manufacturers extract it and sell it separately, since it is a valuable commodity in its own right — which is part of why commercial bars can leave skin feeling tight. A cold-process handmade soap keeps all of it, and glycerine is a humectant that draws water to the skin. That is the main reason a handmade bar feels gentler, more than any single added ingredient.
Olive oil makes a particularly mild soap with a creamy, low-bubble lather. It is the basis of Castile soap, and it has been made around the Mediterranean for centuries for the same reason it is used here: it is the gentlest of the common soap oils.
Lavender
The most familiar soap scent there is, and one of the few that genuinely suits everyone — clean, herbaceous and neither sweet nor sharp. It works well as a bathroom bar and particularly well as a bedside or guest-room soap.
A note on colour: naturally scented soaps do not stay lilac. Lavender essential oil is colourless, and any purple in a soap comes from a colourant. A cream or oatmeal-coloured bar is what an uncoloured lavender soap looks like.
Making it last
The one thing that matters. Keep it out of standing water. A bar left in a puddle absorbs water, goes soft and dissolves quickly. Use a draining dish or slatted rack and let it dry fully between uses — kept dry, an olive oil soap hardens and improves with age.
Note
For external use. Avoid the eyes. If your skin is reactive, test on a small area first — essential oils are natural but not automatically hypoallergenic. Handmade soaps vary slightly in colour, size and finish between batches.