Cold Process vs Melt and Pour Soap: Quality Differences Explained

If you’ve ever browsed a craft market or DIY tutorial, you’ve probably seen both cold process soap and melt and pour soap mentioned side by side. On the surface they can look similar – pretty bars, lovely colours, tempting scents – but under the hood, they’re very different creatures.

As a cold process artisan, I’m a little biased, but I also respect melt and pour as a useful creative medium. The key is understanding what each method can and can’t do, especially if you care about ingredients, skin feel and long-term value.

In this post, I’ll walk you through the real quality differences between cold process and melt and pour so you can choose the right bars for your bathroom, gifting and even your own craft experiments.

What Is Cold Process Soap (Recap)?

Cold process soap is made from scratch by combining plant oils or butters with a lye solution, allowing saponification to occur and then curing the bars for several weeks. Our dedicated article on cold process soap making goes into more detail, but the main points are:

• You choose every oil and its percentage

• You control superfat (extra unreacted oil left in the bar)

• You retain the naturally formed glycerin

• You allow a full 4–6 week cure for mildness and longevity

Scientific work on cold saponified soaps confirms that this method can preserve more unsaponified fatty matter and certain plant components than more intensive processing, supporting a conditioning, emollient feel.

What Is Melt and Pour Soap?

Melt and pour soap is usually a pre-made glycerin-based base that you buy in blocks. You then melt it gently, add fragrances, colours or botanicals, and pour it into moulds to set.

Many melt and pour bases are made with synthetic detergents alongside soap, plus added glycerin, sugar and solvents like propylene glycol to keep them transparent and easy to remelt. Educational blogs such as Botanie Soap's overview of soap pH and formulating guides from natural skincare schools often point out that these bases are designed for convenience and clarity rather than pure minimalism.

That doesn't make melt and pour "bad", but it does mean you're starting from someone else's formula, not your own.

Ingredient Control: From Ground Up vs From a Block

For me, this is the single biggest difference:

• With cold process, I see every ingredient before it ever becomes a bar: each oil, the exact amount of lye, the botanical powders, clays and essential oils. That level of control allows me to design moisturising bars like those we celebrate in our guide to top ingredients for soft, hydrated skin.

• With melt and pour, the base ingredients are already decided. You can add colour and scent, perhaps a sprinkle of herbs, but the cleansing agents, solvents and stabilisers are baked in.

If you're trying to avoid particular surfactants or sugar alcohols, reading melt and pour labels carefully is vital. In contrast, when you pick up a small-batch cold process bar, you can often recognise most of the ingredients at a glance.

Skin Feel: How Do They Compare?

Both cold process and melt and pour can feel pleasant on the skin, but in my experience they do so in different ways.

Cold Process: Creamy, Nourishing, "Weighty"

Well-formulated cold process bars tend to feel creamy and substantial, with a satisfying, cushiony lather, balance cleansing with conditioning (especially when crafted with butters and good superfatting), and retain natural glycerin produced during saponification, which supports hydration.

We looked at glycerin in depth in our post on glycerin in handmade soap, drawing on dermatology research that shows glycerin's role as a humectant supporting barrier function and comfort.

Melt and Pour: Slick, Glassy, Sometimes "Squeaky"

Glycerin-rich melt and pour bases often feel slick or glassy on first contact, with a smooth glide, can rinse to a slightly more "squeaky" finish depending on formulation, and may sweat or bead with moisture in humid bathrooms because of their high glycerin content.

Some people enjoy the shiny, jewel-like look and quick gratification of melt and pour bars. Others find they miss the "buttery" richness and weight of a well-cured cold process soap, especially in drier climates or during winter.

If you're trying to support dry or sensitive skin, I usually recommend looking for simple, well-cured cold process bars and pairing them with emollients as advised in sources like the NHS overview of emollients for dry skin conditions.

Longevity and Value

Because of their different compositions, cold process and melt and pour bars don't always last the same length of time in real bathrooms:

• Cold process bars made with a good balance of hard and soft oils, cured for several weeks and kept on a draining dish, can last a surprisingly long time

• Melt and pour bars may dissolve faster if they're high in glycerin and not allowed to dry fully between uses

Part of our motivation in articles like zero-waste bathroom: how switching to bar soap reduces plastic is to highlight that a well-made bar is not just eco-friendlier – it can also be economical when it's formulated and cured to last.

Customisation and Creativity

This is where melt and pour shines for beginners and children. It's much safer from a chemistry standpoint because you're not handling raw lye – the base has already been saponified or formulated. You can melt, colour, embed toys, and experiment with layering without waiting weeks to cure.

For families or absolute beginners who want a fun craft afternoon, melt and pour is a lovely option. I would still encourage you to check the base ingredients and choose one that aligns with your values – perhaps a more naturally oriented formula, if available.

For deeper, more ingredient-focused creativity, cold process offers another level. You can design bars for different skin needs, as we do in our posts on sensitive skin bars and clay or charcoal soaps. You can experiment with plant infusions, milks, butters and clays in ways melt and pour bases may not tolerate as well.

pH and Skin: Are There Big Differences?

Both cold process and most melt and pour soaps are alkaline, typically around pH 9–10. Studies measuring the pH of natural soaps and their effect on skin show that:

• Healthy skin normally has a slightly acidic surface pH below 5.5

• Washing with soaps temporarily raises skin pH, but it usually returns to baseline after a few hours if the barrier is intact

A recent paper examining natural soaps made by cold and hot processes noted that while pH is broadly similar across traditional soaps, formulation details and usage patterns make more difference than the label "cold" or "hot".

Melt and pour bases that include synthetic detergents may sometimes be formulated closer to the skin's natural pH, but that's not guaranteed – it depends heavily on the manufacturer.

In our own work, we focus less on chasing a specific numerical pH and more on keeping recipes simple and gentle, ensuring full cure for cold process bars, and encouraging good habits like moisturising after washing, as per NHS and dermatology guidance.

When I Would Choose Melt and Pour (and When I Wouldn't)

Even as a committed cold process maker, there are moments where I'd say melt and pour makes sense:

Good uses for melt and pour:

• Craft projects with children where safety is paramount

• Clear soap designs with embeds or suspended items

• Very small, decorative guest soaps and favours where appearance matters more than deep ingredient tailoring

Places I prefer cold process:

• Everyday body and face washing, especially for dry or sensitive skin

• Bars designed to support specific routines, like the ones we talk about in building a simple daily skincare routine

• Gifting where I want to highlight craftsmanship, slow curing and carefully chosen oils

Ultimately, I see melt and pour as a creative medium, and cold process as a from-the-ground-up craft.

Frequently Asked Questions

1. Is cold process soap always more natural than melt and pour?

Not always, but often yes in practice. Cold process gives you complete control over every ingredient, so it's easier to avoid unwanted additives. Melt and pour bases can be naturally leaning or quite synthetic depending on the brand, so reading labels carefully is essential.

2. Which is better for very sensitive skin?

For sensitive or reactive skin, I usually recommend a simple, fragrance-light cold process bar with a full cure and rich oils – the approach we take in our guides on sensitive skin bars and moisturising ingredients.

3. Does melt and pour soap still count as "handmade"?

In a sense, yes – you are hand-crafting the design, scent and presentation. But from my perspective as an artisan, there's a distinction between hand-assembled (starting with a pre-made base) and handmade from scratch (designing the recipe and making the base yourself).

4. Which type should I buy if I care about long-term value and eco-impact?

If you want bars that last well and reduce plastic, a hard, well-cured cold process bar is hard to beat. Our post on creating a plastic-reduced bathroom with bar soaps touches on how durable bars support low-waste, low-clutter routines.

If you'd like to experience the difference that thoughtfully formulated cold process bars can make, you're warmly invited to join our waiting list via the Shop Now page. When new small batches finish curing, you'll receive a gentle nudge – no hard sell, just an invitation to bring a little more craft and comfort to your daily wash.