Behind the Bar: Hot Process vs. Cold Process — What’s the Real Difference?

brushwoodcorners
Nov 25, 2025
3 min read

If you've ever dipped a toe into the world of handmade soap, you’ve probably heard these two terms tossed around: hot process and cold process. At Brushwood Corners, I use both depending on the batch, the recipe, and what I’m trying to achieve. But each method creates a bar with its own personality — its own look, feel, and rhythm in the soap studio.

Today we’re walking behind the bar to break down what truly sets these two styles apart.

What Is Cold Process Soap?

Cold process is the classic, old-fashioned method of soapmaking — the one most people picture when they think of handcrafted soap. Oils and lye water emulsify, trace thickens, and the magic happens naturally as the batter cures.

Here at Brushwood Corners, cold process is how I make nearly all of my signature bars.

My standard recipe includes:

Tallow
Goat’s Milk (100% milk replacement)
Olive Oil
Coconut Oil
Lye
Castor Oil
And often a touch of sodium lactate for firmness

Cold process gives me that creamy pour, smooth texture, and the ability to swirl, layer, and design bars the way my customers love.

Pros of Cold Process

Smooth, creamy, artisan finish
Endless design possibilities (swirls, layering, embeds)
Mild, gentle lather
Long-working time for creative pours

Cons of Cold Process

Requires a 4–6 week cure time
Colors may morph during gel phase
Fragrances can accelerate trace

“Cold process gives you time. Time to swirl, time to sculpt, and time for the bar to become what it’s meant to be.”

What Is Hot Process Soap?

Hot process speeds the whole thing up by cooking the soap batter with heat — usually in a crock pot or oven. The soap goes through the saponification phase before it’s molded, creating a more rustic, textured bar.

It’s perfect when I want a quick turnaround or when ingredients behave better after the cook.

Pros of Hot Process

Soap is technically ready to use immediately
More control over tricky fragrances (they go in after the cook)
Rustic “old-world” texture
Less risk of designing acceleration

Cons of Hot Process

Thick, mashed-potato texture (limited design options)
More hands-on attention during the cook
Finished bars look more rustic and rugged
Still benefit from a short cure to harden fully

“Hot process is fast, honest, and rugged — like soap that got up at dawn and put in a full day’s work.”

Which Method Do I Use at Brushwood Corners?

Both — it depends on the project.

Cold process is my signature style for the Brushwood Corners line. It’s how I achieve smooth bars like Re-Energize, Pure, Re-Imagine, and Morning Dew.

Hot process is what I reach for when I need:

A lightning-fast turnaround
A difficult fragrance
A bar with a rustic farmhouse finish
Testing batches for new products

In short:

Cold process for beauty.
Hot process for utility.

Each plays a role in my small-batch rhythm.

How to Choose Which Method Is Right for You

If you’re crafting for yourself: pick the vibe you want.

If you’re crafting for business: consider workflow, curing shelves, deadlines, and fragrance behavior.

Choose Cold Process If:

You want intricate swirls
You sell visually aesthetic bars
You enjoy the slow craft style
You have cure-rack space and time

Choose Hot Process If:

You need soap ASAP
You use finicky fragrances
You prefer a natural, rustic look
You want to add certain ingredients after saponification

“There’s no right or wrong way to make handcrafted soap — there’s just the way your hands work best.”

Final Thoughts

Hot process and cold process soapmaking both have a place in the heart of a handmade maker. One gives you art; one gives you speed. One gives you silky pourable batter; one gives you warm rustic texture.

And here at Brushwood Corners? I love them both.

Thanks for stepping behind the bar with me today. If you’re curious about the next batch I’m pouring, or want to stay in the loop for new releases, don’t forget to follow along at brushwoodcorners.com/blog or visit the shop to see what’s curing on the rack.

Thank you for spending a little time here with me today at Brushwood Corners.

Every bar, every batch, every story behind the work means the world to me — and I’m grateful you’re part of this small, handmade journey.

If you’d like to follow along, you can always:

Visit the shop → www.brushwoodcorners.com