Natural Bar Soap Guide: How It's Made & How to Choose

Natural bar soap is true soap made by reacting plant oils with lye, then curing the bars for weeks until they're hard, mild and long-lasting. Many drugstore "beauty bars" are synthetic detergents. A natural, cold-process bar keeps all of the glycerin that forms as it's made, which is a big part of why it feels different on your skin. This guide explains how our bars are made, what goes into them, and how to choose the right one.

In this guide: What is natural bar soap? · How we make it · What's in our bars · Which bar is right for you? · Bar soap vs body wash · How to make a bar last · FAQ

What is natural bar soap?

All true soap starts the same way: oils or fats react with an alkali (lye) in a process called saponification, and the result is soap plus glycerin. "Natural" bar soap is built on plant oils and butters, with natural additions such as botanicals, clays, goat milk or honey, rather than synthetic surfactants, and it isn't stripped of its glycerin afterwards.

That last point matters. Some large commercial soap makers remove glycerin to sell separately, and many bars on store shelves aren't soap at all: they're detergent bars built on manufactured cleansers. Both can clean well. They just behave differently on skin, which we explain in castile soap vs regular soap vs detergent.

How we make our bar soap

We use the cold-process method, by hand, in small batches in Canada:

1. Mix. Plant oils are warmed to a controlled temperature and combined with a lye solution.
2. Trace. The mixture is stirred until it thickens as saponification gets under way, then scent and botanicals are added.
3. Pour and cut. The soap is poured into moulds, left to set, and hand-cut into bars.
4. Cure for 4 to 6 weeks. The bars rest on racks while the last of the saponification completes, excess water evaporates, and each bar becomes harder, milder and longer-lasting.

Because nothing is extracted, the glycerin that forms during saponification stays in the bar. And once the bars are cured, no lye remains: it has all been used up turning the oils into soap. If that sounds surprising, our article on what lye is and why all real soap is made with it walks through the chemistry.

What's in our bars

Every Mountain Sky bar starts from the same base, then each recipe adds its own butters, oils, botanicals and scent:

• Coconut oil gives a rich, bubbly lather that rinses clean.
• Palm oil (RSPO-certified sustainable) makes a hard bar that lasts. We use sustainably sourced palm certified by the Roundtable on Sustainable Palm Oil. Read more in is palm oil bad in soap?
• Canola oil adds a mild, conditioning feel.
• Sodium hydroxide (lye) turns the oils into soap and is fully used up by the time the bar is cured.
• Butters and specialty oils such as shea, cocoa and sal butters, and almond, rosehip, meadowfoam, avocado or sea buckthorn oils, depending on the bar.
• Botanicals and minerals such as oatmeal, goat milk, honey, activated bamboo charcoal, Canadian glacial clay, pumice and natural mineral colours.
• Scent from an aroma blend of essential oils and naturally derived aromas.

Reading a soap label: real soap lists either saponified oils (names like sodium cocoate) or the oils together with sodium hydroxide, which is how our labels show it. A bar that lists sodium lauryl sulfate, sodium cocoyl isethionate or similar cleansers is a detergent bar.

Which bar soap is right for you?

All of our bars are made for everyday use on the body. Here's how they differ:

• Sensitive or dry-feeling skin: Goat Milk and Oats is designed for sensitive skin, with goat milk, oatmeal and shea butter. Honey Almond and Vanilla Cream (shea, cocoa and sal butters) are our richest, creamiest bars. All our bars are scented; if you need fragrance-free, try our unscented liquid castile soap.
• A deeper clean for oily skin: Charcoal Cleanse with activated bamboo charcoal, or Canadian Glacial Clay with mineral-rich clay and avocado, carrot and pumpkin oils.
• Rough skin, feet and hard-working hands: Tea Tree and Mint with Canadian pumice, or Anise Rebar with pumice.
• Freshness after workouts: Kali Spice with cinnamon, turmeric and neem oil, or Tea Tree and Mint.
• For the scent: Lavender Dream (calming lavender), Wild Rose (rosehip and pomegranate oils), Herbal Pine Eucalyptus (pine, eucalyptus and fir) and Sweet Cranberry Peony.
• Best value and zero waste: our bar soap seconds are the same bars that didn't make the cut on looks, and our rebar soaps are made from repurposed soap pieces.

Vegan? Every bar except Goat Milk and Oats and Honey Almond is made without animal-derived ingredients. Our seconds are an assorted mix, so they may include those two.

If you have a skin condition, check with your doctor or pharmacist before switching cleansers, and try any new soap on a small area first.

Bar soap vs body wash

Most liquid body washes are detergents, and like any liquid cleanser they are mostly water in a plastic bottle. A natural bar is concentrated soap with a short ingredient list and no bottle at all. Body wash can be the better pick if you'd rather not share a bar, or if you have very hard water, where soap can leave more residue. If you like a liquid but want true soap, our liquid castile soap is true soap in liquid form.

How to make a bar of soap last

A standard 135 g Mountain Sky bar typically lasts 4 to 6 weeks of daily use. To get the most from it:

• Keep it on a draining soap dish so it dries completely between uses.
• Keep it out of the direct spray of the shower.
• Lather in your hands or on a cloth rather than rubbing the bar over your whole body.
• Cut a new bar in half and keep the second piece dry until you need it.

Have a question we haven't answered? Contact us, or browse all natural bar soaps made in Canada.