How to Make Rosemary Mint Tallow Soap (Cold-Process)

You are going to love this DIY Rosemary Mint Tallow Soap Recipe. It’s as pretty as it is functional, and it uses all-natural ingredients for a fun and moisturizing soap.

Rosemary brings the earthy calm, peppermint adds a cool zip, and tallow makes your skin feel like velvet. It’s like a garden spa in bar form. This rosemary and mint soap combines the skin-loving properties of tallow with the natural benefits of clay and essential oils. Plus, it’s a beautiful green that’ll look great in any bathroom. 

Check out our How to Render Tallow Tutorial or our How to Make Tallow Soap Tutorial for the basics of soap making. For other tallow soap recipes, try our 3-Sugar Tallow Soap, Coffee Scrub Soap, Eucalyptus Mint Soap, or Spice Honey Vanilla Soap.

You may also like our how-tos on making Tallow Laundry Soap, Tallow Shampoo Bars, or Tallow Balms.

Why You’ll Love This Soap

If you’re new to soap making, welcome to your next obsession. Rosemary is naturally antibacterial and invigorating, while mint gives that fresh, clean feeling that makes morning showers feel like a spa ritual. Together, they’re a dream team.

Tallow is a great addition to homemade soaps as the fatty acid profiles of rendered animal fat is similar to our own skin barrier. Some of the benefits of animal fats like tallow include increased hydration, gentleness, and barrier strengthening, so it’s a great addition to any homemade skincare. 

Tallow can also be amazing for dry, flaky, or sensitive skin. Just patch test new bars before going full lather.

Notes:

• This recipe makes approximately 11-12 bars depending on cut size
• Always run a soap recipe through a lye calculator — I use SoapCalc.net. 
• Wear eye and hand protection, you do not want to be splashed with lye or unsaponified soap or inhale fumes. Long sleeves, pants, and shoes are great too.
• Do not have children nearby while making soap.
• Make sure you melt fat on low heat, you do not want to scorch it by using higher temperatures.
• Do not use any melt-and-pour soaps (pre-bought soap ingredients often in craft stores) in this process.
• ALWAYS pour lye into water. NEVER pour water into the lye. A hard pocket of undissolved crystals can occur, and you could end up with undissolved lye in your soap, or lye could explode out of your bowl. Be safe!
• Trace is when the soap mixture has emulsified to the stage of looking like pudding. Let some of the soap drop off the blender or a spatula, and you should be able to see it kind of sitting on top of the rest of the mixture.
• Cure soap in a dark, dry area
• I usually fill one soap loaf mold and then have a little extra I put into a small silicone mold.
• Soap making is basically kitchen chemistry. Use a digital scale, and always measure in grams or ounces—never cups. Precision makes the difference between a dreamy bar and a greasy brick.

Common Cold Process Soap Problems

Soda ash? It’s harmless. Soda ash is a white, ashy film that can sometimes show up on soap when you go to cut it. It happens when unsaponified lye reacts with carbon dioxide in the air. The quality of soap is not diminished, and the soap is safe to use. Spray with rubbing alcohol or embrace the rustic look.

Soap separating? Blend a bit longer next time until you get that pudding texture.

Seizing? Soap batter hardening up too fast? Your oils might be too hot or your scent too strong.

Bars getting mushy? Make sure you let the bars cure for 4-6 weeks to harden and make them last longer. Be sure they dry in between uses and don’t sit in a wet puddle.

And if it all goes sideways? Rebatching is always an option! Also, don’t soap while multitasking. One time, I forgot my essential oils. No big deal really, but my scented bar was just perfectly bland.

Homemade Tallow Soap Instructions

Infuse Tallow: I like to weigh and infuse my tallow with rosemary in a small crockpot on the warm setting for 24-48 hours before I plan to make my soap.

Melt Fats and Oils Together: When I begin getting ready to make soap, I will measure and add my olive oil and coconut oil to the crockpot to come to the same temperature as the tallow. This is usually somewhere between 130-165 degrees. 

Prepare Your Work Area and Supplies: Wear gloves and goggles, and work in a well-ventilated area. 

Make the Lye Solution: Put on protective gear before starting this step and make sure you are in a well-ventilated area or outside. Weigh water in a heat-resistant bowl and lye crystals in another bowl. Slowly add sodium hydroxide (lye) to the water (never the other way around!). Stir until fully dissolved and allow the lye solution to cool to around 100 degrees. This will take about 15-20 minutes. 

Cool Oils: Strain oils using a mesh strainer and a cheesecloth into a soap-safe bowl and let the oils cool to around 100 degrees. I also add the French green clay and spirulina to the fats during this time to infuse the color better. This will take around 15-20 minutes.

Combine Lye Solution & Oils: Slowly pour the lye solution into the oils. Using an immersion blender, keep it submerged, and pulse for about 15 seconds. Then use spatula to stir the mixture, switching between pulsing and stirring until you’ve reached a light trace (a pudding-like consistency). Then add essential oils and using the blender, mix until a medium trace is reached.

Texture & Top: After all of the batter is poured into the mold, use a spatula to texture the top of the soap as desired and sprinkle salt on top.

Insulate, Cut, & Cure: Put soap molds on a cookie sheet for easier transporting. Lightly cover the soap with plastic wrap (to help prevent soda ash). Allow it to fully saponify for 24-48 hours before unmolding. Cut into bars of desired size and cure for 4-6 weeks for best hardness and lather. 

Wrap your soap with kraft paper, tie with twine, and pop on a custom stamp or tag. For holidays, add a sprig of rosemary or a wax seal. Instant gift basket envy!

You’re officially ready to rock your first batch of Rosemary Mint Tallow Soap. It’s simple, satisfying, and wildly addictive (don’t say I didn’t warn you). Try it out, tweak it, and make it yours. I’d love to hear about it—or see pics of your gorgeous bars!