How To Make Soap At Home: Learning The Soap Making Methods

There are various methods which can be used to make soap at home. Photo courtesy of flickr user trenttsd.

In our last post, we explained some of the basic foundations for soap making, including ingredients, equipment and method. We have previously gone into detail on soap making ingredients and soap making equipment, so now it is time to expand on the soap making process.

There are various methods which can be used to make soap at home. The basic process for making bars of solid soap is similar for each technique, but there are variations depending on the method used by the soap-maker.

In all processes, the oil or fat is heated, lye and water are mixed, and then the lye-water mixture is combined with the oils.

The mixture then has to be stirred until it achieves the trace stage, at which point it is poured into a mold, and allowed to set, typically for 24-48 hours. The bars continue to harden for another 3 to 8 weeks, depending on the ingredients used.

Cold process method

The most popular method for making soap at home is the cold process method, so named because no external heat is applied to the soap during saponification (the process by which the lye combines with the fats and oils to make soap). With this method, the soap is made from scratch, and while it takes longer than other methods, you have complete control over the quality of the ingredients that go into your soap, and it is typically easier for beginners.

Melt and Pour method

The melt-and-pour method involves taking pure glycerin (animal or vegetable derived), which is always in liquid form, and solidifying it by adding other chemicals. The lather is created by adding pure detergents. Natural ingredients may be added to this variety of soap, but the glycerin base is synthetic, and this method can be expensive, as you are making soap from a by-product of other soap.

However, it is quicker, more convenient, and somewhat safer than making soap from scratch. Also, there is no need to wait weeks for the soap to cure; the bars are ready to use as soon as they cool and harden.

Bars of fragrance- and dye-free soap base can be purchased from many craft and soap supply stores. (You could also try to find some variety of unscented, additive-free soap in a grocery or health-and-beauty store.)


Rebatching refers to the process of melting soap scraps, or chunks of soap base, and remolding them.

Rebatching is useful if you have soaps that are warped, or otherwise aesthetically flawed, but still usable; it also helps to extract the full medicinal or beautifying benefits from any herbs you have added to soap. The fresher the soap is, the better, because the longer it cures, the less moisture it contains, and the harder it is to melt.

As with the melt-and-pour method, as soon as the soap hardens and cools, it is ready to use.

Hot process method

The hot-process method differs from cold-process in that external heat is applied after the fats and oils are mixed together. Instead of allowing saponification to take place during the molding stage – which takes a long time – saponification takes place before the soap is molded.

If you want to use a natural lye solution, such as potash, instead of 100% lye, hot-process is the best method to employ because the hot-process method requires less exact measurements than the cold-process method, since saponification is “forced” instead of taking place on its own.

In the hot-process method, the mixture is heated over a double-boiler, or in a crock-pot, during the trace stage, and the soap is, quite literally, “cooked” to achieve more rapid neutralization. The crock-pot method is usually preferred because the temperature is easily regulated, and the soap is less likely to burn.

Unlike cold-process soap, hot-process soap can be used immediately after it has cooled and hardened, because it should be completely neutralized already; therefore, there is no curing time necessary.

However, it is still a good idea to cure the soap, because the soap may still be soft or spongy, and may not lather properly, or last as long.

Warm process method

The warm-process method is, as you may guess, somewhere between the cold-process and hot-process methods. Instead of insulating the soap with blankets while it is in the molding stage, or boiling it to achieve faster saponification, the filled soap molds are heated in an oven.

Full boiled method

The full-boiled method is typically favored by commercial soap-makers. All ingredients are added at once, in a large container, and heated to cause saponification. Glycerin is a by-product created via this method. The glycerin is typically removed by commercial soap-makers, and sold; however, your soap, with the glycerin still in it, will be naturally more moisturizing and skin-conditioning than commercial bars.

Transparent method

The transparent method is utilized to make clear soap; alcohol is added to the other ingredients to prevent crystallization while it cools and solidifies. Lots of creative projects can be made with this variety of soap. It’s great for innovative and adorable gifts. Transparent soap is sometimes called glycerin soap, but this is a misnomer, since glycerin isn’t utilized at all during this process. One downside to transparent soap is that, because of the alcohol added to the mixture, it can be somewhat drying for some skin types.

Liquid method

There are two distinct options for creating liquid soaps. The liquid methods each resemble cold process and hot process methods, with some important differences. We go into much more detail on liquid soap methods in this article (please click to read more).

Take the next step

Download our FREE ebook, ‘How To Make Soap At Home’, by clicking here.

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