Table of Contents
- What Is The Action Of Soap With Hard Water?
- What Is Hard Water?
- How Does Hard Water Affect Soap Making and Soap Quality?
- Is Soap More Effective In Hard Water?
- How To Overcome The Challenges Of Using Hard Water To Make Soap?
- Conclusion
What happens when soap is added to hard water? Hard water contains high levels of dissolved minerals, such as calcium and magnesium.
As a soap maker, I’ve had to change location sometimes, and I notice some changes in my soap lather and some scum in between my fingers after taking my bath.
And of course, I did my research and found that one of the problems with using soap with hard water is that the soap reacts with the minerals in the hard water and forms a grey, scummy residue called soap scum.
In this article, I will review soap reactions with hard water and possible solutions when you find yourself as a soap maker in an environment with hard water.
Let’s start!
What Is The Action Of Soap With Hard Water?
Before getting into the action of what happens when soap is added to hard water or when you use hard water to make your soap, let’s understand what soap is.
Soap is a substance that helps remove dirt, grease, and bacteria from various surfaces.
Soap is made of molecules with two ends: one is hydrophilic (water-loving), and the other is hydrophobic (water-hating).
When soap is dissolved in water, the hydrophilic end attaches to the water molecules, and the hydrophobic end attaches to the dirt or grease molecules.
This way, soap forms tiny bubbles called micelles that trap the dirt or grease and wash them away with water.
Also, Hard water contains bicarbonates, chlorides, and sulfates of Ca2+ and Mg2+.
These combine with soap molecules to form precipitates of calcium and magnesium salts in soaps, thereby creating soap scum and making soap less lathering.
What Is Hard Water?
Water hardness is a measure of how much dissolved minerals are present in water.
The more minerals in the water, the harder it is. The most common minerals that cause water hardness are calcium and magnesium, which come from rocks, soil, and groundwater.
Hard water can have adverse effects on household appliances, plumbing, and laundry as well.
For example, hard water can cause scale buildup on pipes and faucets, reduce the efficiency of water heaters and dishwashers, and make clothes look dull and feel rough.
It also can affect the taste, smell, and appearance of water and cause scaling or deposits on pipes, appliances, and fixtures.
As earlier stated, the problem with using soap with hard water is that the soap reacts with the minerals in the hard water and forms a grey, scummy residue called soap scum.
Soap scum reduces the lathering ability of soap and makes it harder to rinse off the dirt or grease.
Soap scum also sticks to the surfaces and creates a dull, filmy, or streaky appearance—I’ve experienced it.
Moreover, soap scum can harbor bacteria and fungi that can cause infections or allergies. So, eczema sufferers and sensitive skin people find that this is a problem.
Because All of soap scum from the hard water gets trapped in the pores of your skin and dries your skin out.
How Does Hard Water Affect Soap Making and Soap Quality?
The chemical reaction between soap and hard water is as follows:
Ca^(2+) (aq) + 2 C_(17)H_(35)COONa (aq) -> Ca(C_(17)H_(35)COO)_(2) (s) + 2 Na^(+) (aq)
Mg^(2+) (aq) + 2 C_(17)H_(35)COONa (aq) -> Mg(C_(17)H_(35)COO)_(2) (s) + 2 Na^(+) (aq)
The calcium and magnesium ions in the hard water combine with the soap molecules, forming insoluble salts that precipitate out of the solution.
These salts are the soap scum that float on the water or stick to the surfaces.
Soap scum affects soap making in ways that it causes:
Soda ash: a white film that forms on the surface of soap bars, which can ruin the appearance and texture of soap
D.O.S.: dreaded orange spot, ugly but harmless oxidation of some of the soft oils in soap, which makes the soap susceptible to rancidity and discoloration
Poor lather: hard water inhibits the formation and stability of soap bubbles, which can make soap less enjoyable and effective to use.
In hindsight, before I started my soap business or soap-making, there were times I used soap to do my laundry, and it wouldn’t just lather that’s because the water was hard.
Some soap recipes are more or less suitable for hard water, depending on the type and amount of oils, additives, and chelators used.
Chelators are substances that bind to the minerals in hard water and prevent them from reacting with soap.
Some common chelators used in soap making are citric acid, sodium citrate, and EDTA.
Generally, soap recipes that have higher percentages of hard oils (such as coconut, palm, or lard), lower superfatting levels, and chelators are more compatible with hard water than soap recipes that have higher percentages of soft oils (such as olive, sunflower, or avocado), higher superfatting levels, and no chelators.
Is Soap More Effective In Hard Water?
No! Due to the hard water composition, soap is less lathering when using hard water to do your laundry, wash your hands, or formulate soap.
It is worth mentioning that hard water only affects the soap lather, not the cleaning ability. Soap in hard water is cleaning but less lather.
How To Overcome The Challenges Of Using Hard Water To Make Soap?
You don’t have to relinquish your soap-making hobby if hard water is the only water available to you.
There are some solutions and alternatives that can help you overcome the challenges of using hard water to make soap, such as:
Use distilled water or rainwater instead of hard water: distilled water and rainwater are free of minerals and other impurities that can interfere with soap-making and quality.
You can buy distilled water from grocery stores or pharmacies or collect rainwater from a clean source and filter and boil it before using it.
Adding chelators to the water or the soap batter: chelators are substances that bind to the minerals in hard water and prevent them from reacting with soap.
Add chelators, such as citric acid, sodium citrate, or EDTA, to the water before adding the lye or to the soap batter after reaching trace.
Chelators reduce soap scum, increase rinseability, and boost bubbles.
Testing the water hardness and adjusting the soap recipe accordingly: you can try the water hardness using a water hardness test kit, which can be bought online or from hardware stores.
The test kit will tell you how many grains of hardness per gallon (mpg) your water has, and you can use this information to adjust your soap recipe accordingly.
For example, you can increase the percentage of hard oils, lower the superfatting level, or add more chelators to your soap recipe if your water is challenging.
Using a water softener or a vinegar rinse for washing soap: a water softener is a device that removes the minerals from hard water and replaces them with sodium or potassium ions, which do not react with soap.
You can install a water softener in your home or a portable one for your soap-making water.
However, my best option is distilled water because that is what I use for my soap-making.
Conclusion
In conclusion, adding hard water to the soap-making equation introduces unique challenges.
However, armed with knowledge and the proper techniques, soap makers can navigate these challenges and produce high-quality products.
Whether it’s incorporating chelating agents or opting for water-softening methods, understanding the interplay between hard water and soap is vital to mastering the art of soap making.
