A handmade olive oil soap with ground coffee, from Daki, a small Portuguese artisan soap works.
The kitchen soap
This one has a genuine, practical job, and it is not the one people expect. Coffee grounds neutralise the smell of garlic, onion and fish on the hands — not by covering it, but because the sulphur compounds responsible bind to the coffee. Anyone who cooks seriously should keep a bar of coffee soap by the kitchen sink. It works when ordinary soap does not.
The grounds also make it a mild exfoliant, which suits hands, elbows and feet rather than the face.
Why handmade olive oil soap is different
Soap is made by saponification: an oil reacts with an alkali and becomes soap plus glycerine. The reaction is complete in the finished bar, so no lye remains in it.
The difference is what happens to the glycerine. Industrial manufacturers remove it and sell it separately, because it is valuable — which is part of why commercial bars can feel stripping. A handmade cold-process soap keeps all of its glycerine, and glycerine is a humectant that draws water to the skin. That, more than any added ingredient, is why a handmade bar feels gentler.
Olive oil in particular makes a mild soap with a creamy, low-bubble lather. If you expect a big foam you may think it is not working — lather and cleaning are unrelated, and the foam in most commercial products is there because shoppers expect it.
Making it last
This is the single thing that determines whether a handmade soap lasts a month or a week. Keep it out of standing water. A bar left in a puddle in the soap dish absorbs water, goes soft and dissolves away. Use a draining dish or a slatted rack, and let it dry fully between uses. Kept dry, an olive oil soap actually hardens and improves with age.
Note
For external use. Avoid the eyes. Handmade soaps vary slightly in colour, size and finish between batches.