For homemade soap makers, dealing with soda ash can be a frustrating hassle. Those unattractive white spots and powdery residue mar the appearance of otherwise gorgeous handcrafted bars. While soda ash sometimes feels inevitable, there are actually several effective alternatives for preventing it without compromising on quality. By adjusting techniques and ingredients, it’s totally possible to craft beautiful soda-ash-free cold-process soaps.

The Problem with Soda Ash

What is soda ash?

In soapmaking, soda ash refers to the crystalline sodium carbonate deposits that form on cold-process soap bars as they cure and dry out. It appears as a white, chalky powder or crust on the surface of the soap. Chemically, soda ash is created when the lye water in CP soap reacts with carbon dioxide in the air.

Why Homemade Soapers Use Soda Ash

Many handmade soap makers purposefully add sodium carbonate, commonly called washing soda or soda ash, to their soap recipes. Using a small amount of soda ash helps increase the clarity and hardness of CP soap. The added alkalinity helps neutralize excess oils in a superfatted recipe. With appropriate usage, soda ash helps soap bars achieve an appealing, smooth finish.

Downsides of Using Soda Ash

While soda ash can refine handmade cold-process soaps, it also comes with annoyances. Too much added soda ash can lead to over-neutralization, creating a dry or brittle bar. Even when used correctly, soda ash can still erupt in unattractive white powders on the outer surfaces and edges as the bars cure. This crusty ash residue detracts from the aesthetic look of lovingly handcrafted soap. Besides marring appearance, excessive soda ash buildup directly on the skin can also cause dryness or irritation.

Alternatives to Soda Ash

Adjusting Your Soap Recipe

Instead of using soda ash, you can tweak your soap recipe to prevent ash formation.

Reducing Superfatting Levels

Lowering the superfatting percentages minimizes excess oils, resulting in a less ash-prone bar. Aim for 5-8% superfatting rather than 15-20%. This gives enough extra fat for a conditioning bar without too much unsaponified oil.

Increasing Hard Oils

Adding more coconut, palm, or palm kernel oil creates a harder bar with a low cleansing number. The firmer bar can withstand more alkalinity without turning into ash.

Adding Salt

A pinch of table salt or sea salt increases hardness while lowering the gel phase temperature. This inhibits soda ash without compromise.

Using Other Additives

Rather than soda ash, you can use substitutes like sodium lactate, citric acid, or vinegar.

Sodium Lactate

Sodium lactate performs similarly to soda ash but is generally less ash-promoting. It also hardens soap and boosts lather.

Citric Acid

A small amount of citric acid locks up alkalinity but is milder than soda ash. Too much can lead to seize.


Plain distilled white vinegar gently lowers pH and neutralizes lye without harsh buildup.

Changing Techniques

Tweaking processing and curing methods can avoid ash formation.

Gelling Phase

Encouraging a full gel phase means less soda ash rising up later. Insulate for heat.

Covering Right Away

Wrap bars a few hours after pouring molds to protect from air exposure.

Spritzing with Alcohol

Lightly misting bars with rubbing alcohol helps harden the outer moisture layer to prevent ash.

Perfecting Your Homemade Soap

Testing Different Methods

Getting soda-ash-free soap without compromises takes trial and error. Test batches are key for customizing techniques.

Keep Notes

Record detailed observations about each batch: ingredients, measurements, timing, temperatures, processes, additives, results, etc. Comparing notes highlights what works.

Vary One Element at a Time

Changing too many things at once makes it impossible to pinpoint causes. Alter just one component, like superfatting or vinegar, per test batch.

Assessing for Quality

Evaluate bars over a 4-6-week cure for holistic quality beyond just a lack of ash.


Check for visual appeal—rich colors or swirls if desired, smoothly molded sides, even textures.


Assess the volume, creaminess, and stability of the lather. Re-fatting agents like soy wax or shea butter should contribute bubbly, conditioned foam without stripping.


Confirm the bars fully, yet gently cleanse the skin without dryness or tacky residue. Hard oils should balance cleansing while superfatting moisturizes.


Bars must be cohesive and firm, yet not brittle. They shouldn’t get mushy when wet or have chunks crumbling off.

Balancing Recipe and Process

Adjusting multiple elements simultaneously based on test batches helps perfect custom recipes without soda ash. For example, reduce superfatting while adding hardness via palm oil and sodium lactate. Cover bars after a light vinegar spray and full gel phase by insulating molds in a heating pad. Take notes on how tweaks interact for ideal homemade soap.

Key Takeaways for No Soda Ash Soap

While soda ash may seem inevitable in cold-process soapmaking, there are practical tips for preventing ash formation without losing bar quality. Test batches are crucial for honing recipes and techniques. Lower superfatting, increase hardness with oils or additives, encourage the gel phase, and promptly cover bars after light spritzes of vinegar or rubbing alcohol. Evaluate test bars over a full 4-6-week cure for holistic performance beyond just ash appearance. Balancing adjustments like superfatting reductions, along with hardness boosts from ingredient substitutions and additive inclusions, allow customization for high-quality soda-ash-free soap. With deliberate care and adjustments, homemade soap makers can craft gorgeous bars without unattractive white soda ash marring their creations. It takes persistence through testing, but the journey of mastering ash-free soap is extremely rewarding.

While preventing soda ash on cold-process soap bars may seem extremely difficult, there are several effective alternative solutions to try. With some recipe and technique adjustments, handmade soap makers can successfully craft beautiful, high-quality, ash-free bars.

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