Homemade Goat Milk Coffee Soap- Cold Process Recipe

Homemade goat milk coffee soap is great for all skin types. This simple cold-process recipe smells delicious & looks good enough to eat!

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Cold process methods

Cold-processed soap involves combining a lye mixture with oils to emulsify and cure. The lye reacts with the oils and goes through a process called saponification, resulting in a bar of soap.

The best soaps contain clean, non-toxic ingredients that meet your skin needs.

With this homemade goat milk coffee soap recipe, you will have beautiful, coffee-scented soap bars that lather well, help your skin retain its natural moisture, and are gentle on all skin types.

Using the soap calculator

 The soap calculator will help calculate the amount of lye needed with the different oils to make up a nice soap mixture. 

There are many lye calculators out there. The one I have used and will walk you through is from soapcalc.net.

1. On soapcalc.net, start by clicking “Recipe Calculator” at the top of the page.

2. Next, click the “Type of Lye” as NaOH (sodium hydroxide).

3. Then choose the weight of oils based on how much your soap mold holds. *Note that sometimes a mold will say it holds a certain amount but the actual number is different. My silicone loaf mold says it holds 5lbs when in reality it will hold at most 3.5lbs of soap mixture. I suggest starting a little bit lower and getting a feel for how much soap your molds will hold.

4. Click the “water as % of oils” in the #3 category with the water percentage being 35%.

5. I leave the Super Fat and Fragrance section alone unless I am going to be using a significant amount of fragrance. Then you can plug in those numbers of fragrance oil ounces per pound.

6. Moving down to the Oils, Fats, and waxes, select the oils and kinds of butter listed in the recipe below with their coordinating percentages. Make sure the percentages are equal to 100%.

7. Click “calculate recipe” after the numbers and ingredients have been added. 

8. Then view the printable recipe to see how much lye you will need and if any adjustments will need to be made. Refer to the “Soap Bar Quality” to make sure the numbers are within the ranges listed for quality goat milk soap bars. 

I have tested this recipe tried and true for the best coffee soap but you always want to double-check these numbers before beginning, especially if substituting any ingredients. 

9. Print your recipe to easily have on hand. 

When making goat’s milk soap, I look at the ounces of water needed in my soap recipe to determine how much goat’s milk I will need. 

For goat milk coffee soap, I use a mixture of goat milk and brewed cold coffee as the liquid for adding my lye.

The total ounces of liquid need to be equivalent to the amount of water listed on the soap calculator recipe. 

Tools you will need

*This post contains affiliate links. By using these links I may receive a small commission at no extra cost to you.

Soap mold– I love my silicone loaf mold for an artisan bar soap look, but some pretty patterned silicone molds work just as well. It just depends on the look you are going for in the final product.

The key is to know how much total soap your mold holds to make sure that you make the right amount of soap.

Brambleberry.com or local craft stores can be good places to find quality soap molds.

You can also use empty clean milk cartons, wooden boxes lined with freezer paper, or even silicone baking pans for soap molds. However, these will not tell you how much exactly they hold and will take some trial and error.

Stick blender

Kitchen scale– make sure to choose a scale that can go back and forth between ounces, grams, and pounds for accurate measuring.

Safety goggles

Rubber cleaning gloves

Thermometer- I like to use the touchless, infrared thermometer for ease of use and cleaning.

Plastic pitchers

– one for lye

– one for layering

Ice bath

Small mesh strainer

Glass bowls

– one for a double boiler

– one for an ice bath

Small pot or saucepan to create a double boiler with your bowl (if not using a microwave)

Silicone spatula

​Freezer paper

Wooden skewer for designing

Soap hanger for designing (optional)

Soap calculator

Ingredients and Substitution Suggestions for Goat Milk Coffee Soap

​Note on substitutions: 

It is important to run the soap calculator with any substitutions being made to the recipe below to ensure that the correct amount of lye is used for saponifying your soap.

Different oils, butters, and waxes when mixed with the lye solution create different effects that impact the process of making soap.

For the best conditions for saponification and success in making handmade soap, follow the ingredient amounts given in the soap calculator.

Frozen goat’s milk- I like to freeze my goat’s milk in 1oz. or 2oz. cubes. This makes for easy measuring.

You want to measure out the goat milk weight before it is frozen.

You want to make sure the goat milk is frozen because once the lye is mixed in, the lye heats up very quickly.

Freeze the goat milk to prevent scorching of the milk and solution. Scorching creates a dark brown look to the soap which could be a problem in pure goat’s milk soap or other soap recipes where a dark brown color is not desired.

Goat milk provides a creamy lather in homemade soap and is gentle, making it great for sensitive skin and all skin types. 

Brewed coffee (cold)- I used a cold brew coffee for this recipe but any brewed coffee from natural coffee grounds with no additives will work. Just make sure the coffee is chilled and cold to prevent scorching. 

Olive oil – Olive oil is non-drying and allows the skin to retain its original functions of balancing the skin. If you do not have olive oil, avocado oil may also be used. 

Coconut oil- Coconut oil is very moisturizing in the right amounts. Too much can be drying but in this goat milk coffee soap recipe, there is just the right amount for perfect soap. If you cannot use coconut oil, replace it with sustainable palm oil in the soap calculator. 

Shea butter- Shea butter is nourishing and moisturizing to the skin. It also helps the soap to maintain more structure with the hardness of the butter and creates a bar that is not too hard and not too soft when used in the right amounts. Shea butter can also be substituted for cocoa butter, just make sure to replace it in the soap calculator before making your recipe to ensure the correct amount of lye is used.  

Castor oil- Castor oil adds lather to soap. The properties of castor oil help the skin to retain its natural moisture which makes a great soap for dry skin. 

Essential oils- The coffee naturally adds a nice scent to this soap but if you would like to add to the coffee scent you may. I added cinnamon essential oil for a cinnamon latte vibe.

A note on scents, essential oils, and fragrance oils

I always opt for pure, therapeutic-grade essential oils when scenting homemade soap.

If you want a highly fragrant soap, make sure to calculate the fragrance into the soap calculator for best results.

Using fragrance oils is also an option.

One of the main reasons soap makers opt for fragrance oils is because they produce a stronger scent using less amounts and they are generally cheaper per ounce.

One of the beauties of making soap at home is the control you have over the ingredients.

I like to ensure my soaps are the cleanest, non-toxic product for my family to use.

Despite the extra cost, I have found by using essential oils or leaving my soap unscented, I can avoid harmful chemicals found in fragrances.

I recommend using pure therapeutic grade essential oils if adding scent to soap to meet the variety of skin types and skin needs of even the most sensitive individuals.  

Sodium Hydroxide (lye)- keep stored in a dry place out of reach of children and pets. The chemical reaction of the lye can be very dangerous when not handled with care and caution.

Coffee grounds- for optional exfoliation. Either used grounds or I used an espresso powder that is exclusively fresh ground coffee but ground very very fine for a smoother, less rough exfoliation.

​Whole coffee beans- for optional topping and decoration.

Goat Milk Coffee Soap Recipe 

Frozen goat milk- measured into 2oz. cubes (about 80% of my water replacement)

Cold brewed coffee (about 20% of my water replacement)

Olive oil (50%)

Coconut oil, 76 degrees (28%)

Shea butter (15%)

Castor oil (7%)

Essential oils (optional)

Used coffee grounds or espresso powder (optional)

Coffee beans for topping (optional)

For a single bar of Goat Milk Coffee Soap for testing:

For testing this recipe, you can plug into the soap calculator, the amount a single soap bar holds in a silicone mold (typically 4 ounces) to calculate the recipe.

Continue with the instructions as follows using the correct amount of base oils, liquid, and lye listed on your printed recipe. 

Safety note when making soap

*Using lye, though essential for creating soap, can be very dangerous when not done properly. I always make sure that no animals or children are around during the process of soap-making with lye. 

Instructions for Homemade Goat Milk Coffee Soap

Soap Calculator Recipe

Calculate your recipe using the percentages listed above, into the soap calculator. Print your recipe. 

Gather your tools and ingredients. 

Heat water over the stove until boiling for your double boiler. (If you are using a microwave to melt your oils, you can skip this step)

Using a kitchen scale, measure out your coconut oil and shea butter into the glass bowl.

Melting the oils and butter

Place the glass bowl over the double boiler to begin melting these ingredients. (If using a microwave, heat the oils for 30 seconds at a time, stirring in between sessions, until just melted)

While the oils are beginning to melt, gear up with your safety goggles and gloves. 

​Starting the lye solution

In a well-ventilated area or outdoors, fill a bowl with ice to create an ice bath for mixing your lye solution. This will help the lye remain in a temperature range you can work with and not get too hot.

Measure out the amount of lye you are going to need in its own separate bowl.

Then, fill a plastic pitcher with the correct amount of goat milk ice cubes and cold coffee (80:20 ratio). 

Goat milk to coffee ratio for Goat Milk Coffee Soap

To find the correct amount, I use about 80% goat milk and 20% cold coffee.

For my recipe using the 3.5lb loaf mold, I needed 19.60 ounces of water which I am replacing with the 80:20 ratio of frozen goat milk and coffee.

To round out my numbers, I placed 16 ounces of goat milk cubes into my plastic pitcher (which is around 80%) and topped off the remaining 3.6 ounces with the cold coffee to give me the correct amount of liquid to mix my lye into.

Adding the lye

Next, sprinkle the lye mixture over top of the goat milk and coffee.

DO NOT add the liquid to the lye solution. This will result in a chemical reaction that causes an explosion.

ALWAYS add your lye to the liquids. 

Immediately begin stirring the lye mixture until the ice cubes are completely melted and the lye is fully dissolved. This should take anywhere from 3-5 minutes or so. 

Mixing the lye solution creates fumes that you want to be careful not to breathe in, so being in a well-ventilated area is key.

Once the lye solution is mixed, the ice is melted, and lye granules are dissolved, periodically check the temperature.

You are looking for the temperature to not reach above 80 degrees F. If the temperature begins to climb too high, keep stirring to cool it down. 

Check the oils

While your lye solution is coming to temperature, you want to keep an eye on the temperature of the oils. 

Once the shea butter and coconut oil are just melted, remove them from the heat.

Next, mix in the olive oil and castor oil. 

Move the bowl of oils to a clean counter space. Stirring occasionally.

Ready your space

Bring in your lye solution so you can easily go back and forth checking the temperature of the solution and the oils. You want the temperatures to be within a 10-degree difference before combining.

I like to get my oils down to between 80-90 degrees at least before combining. 

Then, get your stick blender, soap mold, essential oils, coffee grounds, and second plastic pitcher next to your workstation ready to go.

Combining the lye with the oils

​Once the oils and lye solution are within 10 degrees of each other (around 70-80 degrees F), pour the lye solution through the mesh strainer into the melted oils. 

​Then begin blending with your stick blender. Staying close to the bottom of the bowl to prevent splattering. 

Once the lye mixture and oils are combined, add in your essential oils.

Blend until well incorporated.

Trace

You are looking for the mixture to reach a state of trace.

Trace is when you lift the stick blender to drizzle the mixture across the top and you can see lines of the mixture resting on top.

You want this consistency to be on the more liquid side since this recipe sets up very fast. 

*If you are adding layers like I did, move part of the soap mixture into the plastic pitcher. Add the desired amount of coffee grounds to color and texture this layer of soap. 

If you would like the coffee ground exfoliant throughout the entire soap bar for more of a coffee scrub soap, you can skip the layer step and just add the spent coffee grounds to the entire mixture.

Blend until the coffee grounds are well distributed. 

Pour into mold

As soon as you see the slightest sign of trace, pour your soap mixture into the molds. 

To add the layered look, pour the separated mixture into your mold first. This will be the bottom layer.

Periodically pick up your molds and stomp down on the counter a few times throughout the pouring process to release any air pockets throughout the soap.

Then add the remaining mixture to the top, pouring over the end of a spatula to slow the pour and avoid disturbing the bottom layer too much.

Stomp down the molds again to release air.

Design

For a swirled soap you can use the hanger method in the loaf mold to swirl the layers around for a different effect in the end design. 

If using a different type of mold, you can use a wooden skewer to swirl the soap around. 

There are so many different ways you can be creative with soap designs so have fun with it, yet work quickly. 

Once the soap is a thicker pudding consistency, you can add designs to the top if you would like using the wooden skewer for swirls or using the flat edge of the spatula for the lifted look like I have done with these bars. 

Finish off the soap bar by adding whole coffee beans to the top if you want to decorate with those. 

Cover and cure

Cover the soap with freezer paper or a lid if your mold has one. 

Place in the freezer to cure for 3-4 hours. 

After 3-4 hours, move your soap to the refrigerator to cure for at least the next 20 hours.

The next day

Remove the soap from the refrigerator. 

Then, very carefully remove the soap from the mold. 

If using a loaf mold, use your soap cutter to cut 1-inch bars of soap.

Flip the loaf sideways to avoid dragging beans through the bar and ruining the smooth finish.

Save any end bits for testing the soap later. 

Finish curing

Place the bars on a high shelf somewhere with plenty of circulation and room temperature to finish curing for the next 4-8 weeks. This will provide the ideal environment for the soap cure.

Testing your Goat Milk Coffee Soap Bars

After 4 weeks you can test your soap bar. 

If the soap is too soft, it will need a few extra weeks to cure and further harden.

Soda ash is common to form on soap while it is curing. This looks like a light white powder on the soap bars. 

You can use a steamer to steam this off when ready to gift, use, or sell.

Use a soft washcloth with a little soap to lather and test on a small portion of the skin. 

If you notice a light burning sensation or redness forming on your skin after testing the bar, allow a few more weeks for the soap to cure. The fully cured soap bar will be neutral and not leave any redness on the skin.

Once the soap is fully cured, you can store it for up to one year for best results. 

Who doesn’t love a nice soap, especially when it is handmade by you?

The handmade nature of this product makes for such a great gift, especially for coffee lovers.

Notes: 

Make sure the supplies you have used for soap making are dedicated to soap making and nothing else. I like to have a separate box with my supplies to not mix kitchen tools with soap-making tools. 

Resources to reference for making soap at home:

• The Soapmaker’s Companion by Susan Miller Cavitch
• Simple & Natural Soap Making by Jan Berry
• Brambleberry.com

FAQ

Cold process soap making vs melt and pour vs hot process

Cold-processed soap is made using different melted oils and a lye solution. 

• These bars are nice to make because you can easily tailor the ingredients to be all-natural and perfect for your skin type. 

• Cold-processed soap takes at least 4-6 weeks to fully cure and become a nice bar of soap. 

• The curing process is for the sodium hydroxide (lye) to finish the saponification process and become neutral and useable. 

• Without the curing process, lye can burn your skin so make sure to wait at least 4-6 weeks before testing your soap. 

Melt-and-pour soap involves using a melt-and-pour soap base to create your soap. 

• After melting down the soap base, you to add in your essential oil or fragrance oil for your favorite scent. 

• After being poured into soap molds and set to harden, melt, and pour soap bars are fully saponified and ready to use because the lye chemical reactions have already occurred in the prepared soap base.

• Melt-and-pour soap recipes are nice if you need a quick soap bar and do not have time to wait for curing.

You can find a variety of melt-and-pour soap bases such as shea butter soap base, glycerin soap base, or even goat milk soap base. I like Brambleberry.com for sourcing these or our local Hobby Lobby.

Hot-processed soap involves one extra step compared to cold-processed soap and that is adding soap to a slow cooker after reaching a state of trace.

• After some time spent cooking in the slow cooker, the add-ins, colorants, and scents, are incorporated and the soap bar is set to cure.

• A benefit to hot process soap is the increased cure time of these bars. The cure time is increased to 2-3 weeks instead of 6-8 weeks before your soap bars are useable.

• Hot-process bars also last longer on the shelf.

Does goat milk increase the lather in soap?

Yes, the creamy goat milk helps produce a nice lather in this soap.

What does coffee soap do for your skin?

Coffee soap benefits the skin by adding a light exfoliation with the addition of coffee grounds.

​The coffee grounds help to remove dead skin cells, leaving your skin soft and exfoliated.

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Have you been making soap for a while? Is this your first time? Comment below! I would love to know your experience!