Making shampoo bars is a very different process from making body soap in a lot of ways. Unlike body soap, it is important to limit the number of unsaponifiable substances in a bar made for hair. Unsaponifiable substances are the parts of an oil besides the fatty acids. The fatty acids will react with the lye to form soap, but the unsaponifiables remain unchanged. Too much unsaponified matter when making shampoo bars means a sticky film left on the hair after washing. Some oils have a lot of unsaponifiables, such as unprocessed shea butter. Some are naturally low in unsaponifiables, like cocoa butter. The best shampoo bar recipe will have a very low amount of unsaponified substances.
Another difference between making shampoo bars and body bars is that you want to use larger amounts of strong bubbling oils, such as castor and coconut oils, to effectively lift and separate the strands of hair and to attach to grime, allowing it to be washed away. The best shampoo bar recipe will have no more than 50 percent soft oils, such as canola, rice bran, soybean or olive oil, and a high percentage of coconut and castor oils for rich bubbles. If you do not know how to make coconut oil soap, it is important to keep in mind that high coconut oil formulas can overheat easily during gel phase, especially if you have a recipe with honey or sugar. Another difference with high coconut oil soap is that the soap may harden more quickly than usual, and can often be cut the same day it is poured into the mold. (If you find yourself asking, “how does soap work?” click here for more information on the soap making process.)
When making shampoo bars, they should not be superfatted to a high percentage like body soaps, because the residual oils can weigh the hair down. The best shampoo bar recipe will have between 4-7 percent superfat, enough to make the shampoo gentle and to use up all of the lye for soap, but not enough to coat the hair. The recipe contained within this article is for 6 percent superfat.
Below is the best shampoo bar recipe of all that we tried. It was tested on oily and dry hair types, as well as both fine and coarse hair types. The majority of those who tried the sample shampoo bars preferred this recipe over the others. This recipe makes a standard three pound soap loaf, which yields approximately ten bars of soap, depending upon how it is sliced.
The Best Shampoo Bar Recipe
Makes one loaf of shampoo soap, slightly less than three pounds, or approximately 10 bars
- Olive oil – 16 oz
- Coconut oil – 12 oz
- Castor oil – 2 oz
- Cocoa Butter – 2 oz
- Sodium Hydroxide – 4.65 oz
- Beer, left out overnight to go flat – 11 oz.
- Fragrance or essential oils – .5 – 2 oz., according to preference
To start making the shampoo bars, you must begin the day before by pouring 11 ounces of beer into a shallow container and leaving out overnight to go flat. This also reduces the alcohol content of the beer significantly. The shallow container is necessary because more carbonation will be released from the greater surface area exposed. Also, alcohol acts to suppress bubbles, so this is an important step. It is also important because if you add lye to fresh, bubbly beer it is likely to overflow — definitely not a situation you want to encounter. (To learn vital soapmaking safety protocols, click here.) I like to take the additional step of chilling the flat beer in the refrigerator for several hours before using. This prevents scorching of the sugars in the beer when the lye heating reaction occurs. In tests, there was always a small amount of undissolved lye sediment left over in the mixed solution, even after half an hour. I recommend straining the lye solution into the oils when you are ready to make soap.
Here I must offer my sincere apologies, and an unusual suggestion — my apologies for the fact that mixing lye with beer releases an odor, a combination of yeast and wet dog. For this reason, I suggest mixing your lye solution outdoors, or at the very least, adjacent to an open window and with a fan running. The smell dissipates quickly in the finished soap and becomes completely undetectable when cured, leaving behind nothing but the benefits of added vitamins and minerals as well as richer shampoo lather..
When you are ready to make soap, first weigh all of your ingredients. Melt the hard oils (coconut and cocoa butter) together in the microwave or on a burner set over low heat. Warm until just melted enough to be clear oil, not opaque. Blend the melted oils with the room temperature soft oils (olive and castor) and allow the oils to rest until about 75-80 degrees Fahrenheit. Weigh out the beer and the sodium hydroxide. Very slowly pour the sodium hydroxide into the beer in a large bowl, while stirring, to allow for foaming to occur and subside. This may not happen if the beer is flat enough, but it is better to be safe and leave room for the reaction to happen. In our tests, there was always some amount of foaming when the lye was added. Allow the beer and lye solution to cool to room temperature before straining into the base oils. Mix the oils and strained lye solution thoroughly by hand using a nonreactive (non-aluminum) spoon or spatula. Next, use your stick blender in short bursts of 20-30 seconds, alternating with hand stirring, to help the shampoo soap reach medium trace. Once medium trace is reached, add the fragrance, if using, and mix thoroughly. Pour into the prepared mold. If the soap begins to get too hot during gel phase, you can place the soap into the refrigerator or freezer until it cools. This soap hardens fairly quickly and can crumble if cut when cured, so make sure you cut the soap as soon as it is firm enough.
To use a shampoo bar, simply rub into wet hair, massage into scalp, then spread out to the ends before rinsing well. An optional acid rinse, such as a splash of vinegar or lemon juice in water, will make hair feel soft and well conditioned without adding residue.Some people like to infuse apple cider vinegar with herbs or essential oils to make their hair rinse more fragrant.To make a simple infusion for hair vinegar, pack a clean jar with fresh, dry herb leaves, stems and flowers. Fill with apple cider vinegar and cap. You can also add a few drops of essential oils to boost the fragrance of your infusion. Allow at least 48 hours for the infusion to develop before straining and storing in the bath. To use, add a splash to a cup and fill with warm water. Pour through hair. No need to rinse.
By using our recipe, which is low in unsaponifiables that can make hair sticky, and also low in superfat, which can weigh hair down, you can create a good all-purpose shampoo bar suitable for most hair types. An additional acidic rinse will leave hair soft and silky.
Will you try making solid shampoo bars with our recipe? What fragrance or essential oils will you choose? Which herbs will you use in your acid rinse solution? We would be very interested to hear your results.