Why kitchen ingredients appeal to soap makers
Soap additives are anything added to a basic batch of oils, lye and water to change how the bar looks or feels. A few of the most popular come straight from the pantry. Oatmeal and honey, often paired in one bar, are the classic example, with others like milk, yogurt, coffee grounds, cornmeal and spices not far behind.
The appeal is simple. They are familiar, inexpensive, and easy to find. It is worth being clear about what they actually do, though. Soap is rinsed off, so additives mostly change the look, texture and lather of a bar, not the long-term condition of your skin. Claims that a particular additive treats a condition are not something a careful guide can support.
Oatmeal
Oats are popular for their gentle, slightly scratchy texture and their soft, cereal-like look.
Forms. Whole rolled oats are scratchy and can look rustic, but large flakes can be uncomfortable on the skin. Finely ground oats, sometimes called colloidal oatmeal when milled very fine, blend into the batter more smoothly. Many makers grind oats in a blender or coffee grinder for a gentler result.
Effects in a batch. Ground oats can add a slightly creamy feel to the lather and a gentle, mild exfoliation. In the batter, they may thicken things somewhat, so a maker might notice trace arriving faster. Oats also contain some natural sugars, which can contribute a little extra heat.
Practical notes. Use only fine amounts, mixed in at trace, and avoid pieces that are large or sharp. Oat flecks in a finished bar may darken or turn slightly tan, and oats in the bar that stay damp for too long can contribute to spoilage, so make sure the bars cure fully in a dry place. People with oat or gluten sensitivities should be aware that oats are sometimes processed alongside gluten grains.
Honey
Honey is a favorite for its warm, golden associations. In soap, it can add a little extra lather and a sweet, mild scent, though the scent often fades.
The heat issue. Honey is mostly sugar, and sugars make a soap batch heat up more during saponification. A batch with a generous spoonful of honey can overheat in the mold, darken, crack or in extreme cases rise up out of the mold. This is the same issue that comes up with goat milk and other milks in soap, and the same cool-handling habits help.
Using it sensibly. Makers typically use honey in small amounts, often stirred into the batter at light trace. Many recommend avoiding insulating the mold, and some place the soap in a cool spot or even a refrigerator for the first day. As always with unfamiliar additions, follow a tested recipe from a reliable source and keep careful notes.
Color. Honey often turns a bar a shade of tan or brown, sometimes quite deep, and the lighter the batch it goes into, the more noticeable the change.
Other pantry additives
- Sugar or salt. Small amounts can add lather or hardness, though both can also add heat or make the bar more brittle.
- Yogurt or buttermilk. Like other dairy, they bring sugars and proteins and need cool handling.
- Coffee grounds and cornmeal. These offer texture for a scrubbier bar, a theme developed in exfoliating soap.
- Spices and herbs. Cinnamon, turmeric and similar powders are used for color, but spices can irritate skin, and cinnamon in particular is a known problem for sensitive people. Herbs may brown and bleed.
- Fruit and vegetable purees. Often tempting, but their water and sugar content make results unpredictable, and they raise the risk of spoilage.
What to watch for
Several general points apply to nearly every additive.
- Fresh matters. Fresh, dry ingredients are safest. Anything that carries moisture can encourage mold or spoilage in a bar.
- Less is typically more. A little goes a long way. Too many solids can make a bar crumbly or rough.
- Check the batter temperature. Sugary additives heat the batch, so aim for cooler working temperatures.
- Watch for allergies. Any food ingredient can trigger a reaction in someone allergic to it, so patch-test a finished bar and be cautious about gifting without disclosing the ingredients.
- Keep lye safety in mind. Adding extras is exciting, but the batter still contains caustic lye until it has reacted. Wear protective gear, keep children and pets away from the work area and work in a ventilated space.
Expectations versus results
A bar of oatmeal and honey soap can be pleasant, with a mild, creamy feel and a cozy look. Treat that as the main benefit. If your skin is irritated, dry or reacting to something, a gentle product and a conversation with a health professional will do more than any additive. And if a batch with honey comes out a little darker than the picture you had in mind, that is simply how sugars behave in soap.