How to Prevent Soda Ash on Your Cold Process Soap Bars

Soapmakers generally end up with soda ash forming on their bars at least once in their soap making endeavors. Let's take a look at soda ash, what it is, way to prevent it from happening, how to get rid of it when it occurs, and an example of how it can enhance your soap.

What is Soda Ash?
Soda ash is the common name for sodium carbonate. It's a harmless, white powder that can naturally occur on bar soaps as a mineral deposit. It forms when sodium hydroxide (lye) and air (oxygen) come in contact with each other (see below on how to prevent this from happening).

Sodium Carbonate
Na-= sodium hydroxide
O = oxygen

Here is an example of a soap with soda ash (left) and one without (right). Thanks to my friend and colleague, Angela Carillo of Alegna Soap for sharing this example. The bar on the left had been exposed to air during the first 24 hours of saponification, while the bar on the right was not exposed.

Heavy soda ash on the surface of the left bar.
Photo credit: Angela Carillo of Alegna Soap

When Does Soda Ash Occur?
As in the example that Angela provided, this soap set up with soda ash during the period of 24 hours after pouring the soap into the mold. During saponification, or the first 24-48 hours and occasionally a few days into the curing process.


How to Prevent Soda Ash
The easiest, most proactive way to prevent soda ash is by reducing the water content in your soap. I haven't gotten soda ash for 15 years, and I soap at a 38% lye concentration (do not confuse this as water as percentage of oils). This is convenient if you are making soap that you want to set up quickly.

However, if you want your soap to set up slowly such as in the case of swirling or creating intricate color designs, then you won't want to reduce your water content as the soap batter will thicken too quickly on you.

Some people say that spraying isopropyl alcohol (rubbing alcohol) on the soap right after pouring into the mold will prevent soda ash. I've never found this to be true. The theory is that the alcohol helps remove the extra water on the surface layer of the soap. Give it a try and experiment for yourself.

The second best way to prevent soda ash is by simply covering your freshly poured soap AS WELL AS your freshly cut bars with a loose layer of plastic. You can use plastic wrap, a clean trash bag or a plastic table cover. Keep the plastic over the surface of the soap in the mold. After you have unfolded and cut into bars, cover again for 48 hours. If you are using full water content (lye concentration of 28%), then you may want to keep the plastic over the bars loosely for a week.

How to Remove Soda Ash
Here are some ideas to removing existing soda ash from your soap bars:

• Wipe a damp paper towel over the bar.
• Use a steamer to remove the soda ash (yes, some people actually do this).
• Run the bar under water and let dry (wear gloves as this tends to leave fingerprints).

Embrace Your Soda Ash

Soda ash on the top of activated charcoal soap.
Photo credit: Angela Carillo of Alegna Soap

Soda ash can create interesting contrasts in intricate soap designs, as in the one pictured above. Again, a perfect example by Angela on how soda ash can naturally appear simply by the lye in her soap "meeting" the oxygen in the air around it.

Although soda ash can show up unexpectedly and present aesthetically-challenged soap bars, it can also lend itself to complementing colors and designs. There are easy ways to prevent it once you understand that water plays a large part. Most soapmakerss are busy and don't want to be presented with the task of removing soda ash on every batch made. Plastic wrap might be the easiest way to protect yourself against a surprise visit from the soda ash fairies!

What have you noticed about soda ash setting up on your soap?

Do you have any tips on removing or preventing it?

How Much Fragrance for My Soap, Ice Trick and Other Cold Process Soapmaking Tips

Let's dive into some questions I recently received via email regarding cold process soap making. I hope that you'll find them helpful. Do you have other questions? Feel free to leave a comment and I may choose yours as my next blog post!


Q: Do carrier oils and butters lend any fragrance to the soap?

A: Not enough to notice. The only exception that I've experienced is cocoa butter added at 15-20 percent. It results in a light cocoa scent. I find that most of my clients and students want to add essential oils to create a beautifully scented soap. (I no longer use synthetic, fragrance oils. I stopped using them five years ago when I began to have breathing issues around them.)


Q: Is it true that sodium lactate will speed up the saponification process? What's the cure time when using sodium lactate? Is the cure time based on the weight of the soap?

A: Sodium lactate won't speed up saponification. However, it will result in a harder bar. I recommend that you try sodium lactate at 1% of your oil weight. If you've never seen it, it's clear and looks similar to glycerin.

To use, simply stir into cooled lye water (under 130F). However, you may not want to use sodium lactate if you are reducing the water content in your soap. It can cause overheating and cracking, which is a complete bummer.

Also, if you plan to use any liquid with a high sugar content (juices, milk, etc.), I suggest that you try a small batch first to see if the sodium lactate will behave in the batch. It can cause overheating in milk and juice soaps.

Cure time for the soap will be standard, which is around four weeks depending on your formula. For example, if you make a castille soap (100% olive oil), then your bars may take six to eight weeks to cure.

Try using ice in your lye water to keep fumes at a minimum
and to help cool your lye water temperature quickly.

Q: We used ice in our water during the soap making class with you in New York City. Can you remind me of the ratio of ice to water? Does it matter how much? Should I assume the weight of the ice and water should equal the water liquids needed for that particular batch?

A: Great question! And I'm sure many soapmakers will appreciate this tip. Let me first explain that I use ice for two reasons: 1.) to help the lye water temperature drop faster and 2.) to keep the sodium fumes at a minimum, which your lungs will thank you for years down the road.

The maximum amount of ice I recommend is 70% of your required liquid. You'll just replace 70% of your liquid weight with ice, then add the rest in water. Sometimes students ask if ice weighs the same as water, and the answer is yes. And yes, you're right in the assumption that you're going for the total amount of water liquids needed for the batch. The higher the ice amount, the stronger the probability that some of your lye may not dissolve completely. So start with a 50:50 ice to water ratio and you won't run into any problems with the lye not dissolving.


Q: How do I determine how much fragrance to add to my soap batch? When do I add it?

A: You can either add your fragrance to your oils before you begin soaping or you can add them at trace (thickening of the soap batter). I recommend adding them at trace, especially if you aren't sure how they are going to behave once added. Add a small amount at a time. If you see your soap thickening quickly or turning into tiny chunks, stop and quickly pour into your mold. This can happen with floral essential oils and especially fragrance oils, since the latter is made up of different chemical components. We never know how fragrance oils are going to behave. So if you are new to soap making, stick to essential oils like lavender, lemongrass, peppermint and rosemary in the beginning and you'll have very little chance of something going wrong because of them.

The usage rate for essential oils in cold process soap is 0.5 - 1 oz. per pound of oils used in your formula. This doesn't include water. Just your oil weight (olive, shea butter, coconut, etc.) Always weigh your fragrance and rest of ingredients for accuracy as opposed to using measuring cups.

To determine the amount of essential oils/fragrance, take the weight of your formula oils in pounds and multiple by .5 ounces. For example:

3 lb. oil
x .5 oz fragrance
1.5 oz.


Q: Do I have to line my molds?

A: If you are using wood or cardboard, yes. Line it with freezer paper or plastic wrap. If you are using plastic molds, I suggest you use plastic wrap inside the mold for an easy release. However, if you are using silicone molds, you can forgo the plastic wrap.


Q: Can you remind me what the temperature of the lye water and oils need to be before I combine them? Does it matter about the temperature of the essential oil?

Honestly, I don't even check temperatures anymore. I now teach my students to feel the sides of the lye/water and oil containers and get a feel for the temperature of under 120F or 130F. If you are new to soap making, you might want to use a thermometer in the beginning. Under 120F is ideal, but if you are at 130 or even higher your soap will be fine. My favorite temperature is room temp, which is right around 68 degrees in my house this winter.

Thanks for reading. If you're in the New York City area this month, be sure to check out my upcoming workshops!

Alchemy of Cold Process Soapmaking - An Online and New York City Experience

Photo credit: Marla Bosworth
These are the hands of alchemists blending their cold process soaps
with wildcrafted botanicals and healing essential oil blends.

Last month in New York City I shared with students what I have been doing for a lifetime as an alchemist - blending nature with healing modalities. It began when I was a child in central Illinois when I would create infusions with botanicals found walking in the woods, forgaging in fields or in my parents' garden. Later in life when I created my botanical beauty company I began creating soaps in Massachusetts and captured the energy of the Atlantic ocean and Cape Cod in my bodycare line. Then I moved to Jackson Hole, Wyoming where shIe worked with the energy of wildlife, the Rocky Mountains and the plethora of botanicals growing throughout the Grand Tetons.

Customers would come into my Jackson Hole store and tell me how her products envoked memories of hiking on trails in Yellowstone or Grand Teton National Park. They would hold the soap - some knowing and others not - that the vibrational frequency in the soap brought memories and oftentimes emotional healing.

I've taken my knowledge of combining alchemy, higher consciousness and sacred geometry and created a new class for beginning and experienced soapmakers. This workshop is also intended for healers, lightworkers, massage therapists, yoga enthusiasts, and anyone interested in wildcrafting, alchemy, energy healing, sacred earth energies and cold process soapmaking.

Join me on March 24 in New York City for the next workshop. Check out the class here. Not able to travel to New York? Sign up for my new, upcoming online workshop here.


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