Cold Process Soap, Explained For People Who Buy It.

Cold process soap is soap made the slow way. Oils and lye are mixed without cooking, poured into a mould and left alone for weeks. Every bar on The Rangeis made like this. This page explains what cold process soap is, what it changes about the bar in your hand, and what it does not change, whatever another brand's label would like you to believe.

It is written for people who buy soap. If you make soap, you already know all of this and you will find the tone annoying. That is fine. We find a lot of things annoying.

What is cold process soap?

You combine oils with a lye solution — sodium hydroxide dissolved in water. Mixed at a controlled temperature until the mixture emulsifies and thickens. Poured into moulds. Left 24-48 hours while the saponification reaction completes. Unmoulded. Cut. Cured for weeks.

No external heat is applied after mixing. This is the cold in cold process — relative to the hot process method where the soap is cooked until saponification is complete.

It is not actually cold. The reaction makes its own heat, and a freshly poured block stays warm for hours. Cold only means that nobody turns the stove on.

The reaction is called saponification. Oils and lye go in. Soap and glycerin come out. Neither the oil nor the lye survives as itself. That is the entire trick, and people have been doing it for thousands of years.

Cold process vs hot process soap

There are two honest ways to make bar soap from scratch. They use the same ingredients. The difference is heat and patience.

Hot process cooks the batter. Oils and lye are mixed, then heated — in a slow cooker, an oven or a double boiler — until saponification is finished. The soap comes out thick, like mashed potato, and is pressed into the mould. The bars look rustic and slightly lumpy. They can be used sooner, although they still improve with time on a rack.

Cold process cooks nothing. The batter is still pourable when it goes into the mould, so the bars set smooth and dense, and the reaction finishes on its own schedule. Then the bars need weeks on a rack before they are ready to sell.

Neither is better soap. Hot process is quicker. Cold process is slower. We make cold process, and we wait.

There is a third thing sold as handmade soap, and it is worth knowing the name. Melt and pourmeans a ready-made soap base, bought in blocks, melted, coloured, scented and poured into a pretty mould. Some bases are real soap. Many contain synthetic detergents. Either way, the saponification happened in somebody else's factory.

What our cold process involves

A blend of oils — Koroneiki olive oil from our grove as the primary ingredient, with coconut oil, and depending on the soap: avocado oil, mango seed butter, shea butter, sweet almond oil, jojoba oil, castor oil, cocoa seed butter, sesame oil, apricot kernel oil.

Plus whatever makes each soap specific. Almond milk and liquid silk in the Almond Milk. Fresh carrot juice and carrot seed oil in the Carrot. Real fig puree in the Fig. Beeswax and lavender herb in the Lavender. Cucumber extract and arnica in the Spearmint. Pink clay in the Cinnamon.

This is not a simple olive oil and lye formula. It is a calculated blend with a reason for each ingredient.

The amount of lye is calculated for each recipe from the oils in it. Every oil needs a different amount of lye to turn into soap. Too much lye and the bar is harsh. Too little and it is greasy. Nobody guesses.

Why Koroneiki, and why our own trees, is a separate story. So is what makes it Greek olive oil soap, rather than soap that once drove past an olive.

What cold process preserves

The glycerin produced by saponification stays in the bar. Industrial soap manufacturers remove it — glycerin is valuable in other markets. We leave it in because we don't have the industrial equipment to separate it and we don't want to.

Glycerin pulls water out of the air. That is why a handmade bar left in a steamy bathroom can bead with tiny drops of moisture. It is not sweating because it is nervous. It is glycerin doing what glycerin does.

What cold process requires

Time. Olive oil dominant soaps need six to eight weeks of curing. The bar loses water weight and hardens. Ours weigh a minimum of 120g per bar. What goes in comes out properly.

Our soaps air cure on racks for 6 to 8 weeks, in the workshop. Rack space is the real cost of cold process. A bar that is ready to sell in a week is cheaper to make. It is also a softer bar that disappears faster in your shower.

Does cold process soap go bad?

Not the way food does. A dry bar of soap does not grow mould on a shelf, and the lye that made it is gone. What can happen, slowly, is that a little leftover oil goes stale. Most soap makers leave a small amount of oil unreacted on purpose, so the bar is not harsh. Over a long time, in heat or light, that oil can oxidise. You would see small orange spots, or notice a faint smell of old crayons. Soap makers call it DOS — dreaded orange spots — because soap makers should not be allowed to name things.

Storage decides most of it. Keep unused bars somewhere cool, dry and dark, like a drawer or a cupboard, and not in an airtight container. The bar needs air.

Can I melt down cold process soap?

You can try. It will not behave. Cold process soap does not melt into a clean liquid the way a melt-and-pour base does. Grated and heated with a little water, it turns into a sticky paste, which soap makers call rebatching. It is a way to rescue scraps. It does not turn a good bar into a better one.

Our advice: use the soap.

How to make homemade cold process soap?

Oils, lye, water, a scale, a stick blender, goggles and gloves, and a lye calculator that knows the saponification value of every oil in the recipe. Lye is caustic. It burns skin and eyes, which is why it is handled with protective equipment, every time, by everyone.

That is the outline. It is not a recipe, and this is not a tutorial. There are excellent ones, written by people who enjoy explaining it.

If you do make your own, good. You will understand very quickly why ours takes eight weeks and costs what it costs.