All You Need to Know About Moldy Soap


Soap making, the way we know it today, started in the Babylonian civilization. The process hasn’t much changed throughout the centuries and people will continue to use it for generations to come. Whether creating it yourself or just a consumer using soap, many problems can arise if you’re not careful. Today we’re going to answer one of those possible problems: Can soap get moldy?

Soap can grow mold if organic additives are present. generally soap will sit with a pH of 8-10 which prevents growth but add in fruit puree, flower petals or other things in the making process, and you present the opportunity for mold to form and grow.

So, let’s find out more about the why soap gets moldy, and the how to prevent homemade soap going moldy, and everything in between – Let’s jump in.

Molding Soap

Soap can grow mold. Although this should be a rare occurrence, it can happen. Mold requires organic material, water and heat to thrive on any surface and soap is no exception.

If done right and proper, the answer should be “no.” But there are some nuances in the types of soaps available and things like fresh fruit, cooked vegetables and grains can affect it. Mold occurs more with melt-and-pour more than cold process soaps.

Cold-process has a pH balance between eight and ten. This means it’s far too alkaline to sustain mold due to the fact it hasn’t gone through saponification yet. But if there’s organic material in the bar and has poor curing, mold can definitely occur.

Melt-and-pour soap is different than cold-process. It experienced saponification before your use of it and is thus more susceptible to mold when mixing in fruit purees, fresh herbs or other organic substances.

Liquid or foaming soaps are prone to mold because more water is inherent in the product. Distilled water is best because tap, spring and filtered water will introduce mold-promoting organisms.

Organic Matter is often the Culprit

Fresh substances, when added to soap, can have microorganisms because of the water content in the soap and the organic material. This is why it’s always best for soap to contain dried components.

The only time to add fresh ingredients is during the “tracing” stage. If you are making soap yourself, only add in small amounts. As the water evaporates during curing, the water from the herbs, flowers, fruit, vegetables and etc will also evaporate. It is not advisable to add fresh materials any time before that unless you really know what you’re doing.

If you make soap and are new to doing it, stick to tried and true recipes that are simple and easy. Don’t go for the fancy additives until you are confident about your technique and understand how to make it.

Even when you’ve built up the knowledge and faculties for making soap, know that cooked or fresh pieces of plant material can and will ruin your batch.

Remember to keep your work area free of excess moisture and humidity every step of the way. You can do this by having a dehumidifier or a fan while you mix your batter as well as during the tracing and curing processes.

Keeping surfaces disinfected will keep them clean and free of any type of debris. This will help to ensure mold doesn’t grow in your batter.

If you buy your soap, a little investigation and research will go a long way on your part. If it comes from an independent crafter, look up their ingredients and ask the following questions:

  • What type of soap method used: cold press or melt-and-pour?
  • Is it made in a personal kitchen or do they have a reserved area?
  • What are their safeguards against mold?
  • If fresh organic material is used, when do they add it to the batter?

Commercial manufacturers should never sell you a bar of moldy soap. This generally isn’t a problem because they usually have quality checks for this sort of thing before distribution. But if you have any doubts, don’t hesitate to ask questions.

Identifying Mold on Soap

If your soap isn’t used in some time and you see white marks or circles all over it, chances are it’s just dried bubbles from the last use. But if there are strange colors present or it smells funnier than before, it may very well be mold.

Mold will grow throughout the bar and may have started deep within the bar itself. Check the soap by cutting or breaking it in half. If you see the same discoloration and it retains the same rancid smell, it’s a sure sign of mold.

Do not keep the soap, throw it away immediately and don’t forget to wash your hands. If you have any doubts about your soap being moldy, stay on the safe side and just throw it out.

Most soap is safe to use and will not grow mold. Even if your soap reaches its estimated expiration date, it should still be safe to use for a time. If there is any mold, it’s more than likely because fresh materials added during the wrong phase.

Bomb Guru

A bathbomb enthusiast who happened to be in the birthplace of bath bombs as they were born. My passion remains to this day

Recent Content