The Science Behind The Solid Shampoo Bar

From liquid to solid: The evolution of shampoo bars.

As the personal care brands continue to look for the next big innovation, alternate product formats are a great way to differentiate in the market. Consumers are starting to supplement their traditional liquid haircare to innovative solid haircare formats. Unlike their liquid counterparts, solid shampoo bars are compact, lightweight, and require no plastic bottles, making them ideal for consumers seeking to minimize environmental impact without compromising haircare quality.

Solid shampoo bars are gaining a loyal following thanks to advances in formulation and manufacturing that deliver convenience, performance, and scalability.

Industry Growth of Solid Haircare

Previously, solid shampoo and conditioner bars were made at home or with smaller niche manufacturers. As these bars grow in popularity brands need to scale their production with larger manufacturers that can offer regulatory compliance, OTC innovations and support sustainability claims. Shampoo bars also offer significant value with one bar lasting the equivalent of 4 bottles of liquid shampoo.

Bradford Spotlight: We provide effective formulas with naturally-derived ingredients while ensuring consistent quality and performance. Because we routinely meet rigorous regulatory and quality standards across our operations, we can confidently apply this level of oversight to all product categories, while delivering innovative formulations that consumers love.

Unpacking the formulation

Solid shampoo bars are typically more concentrated than their liquid counterparts due to less water in the formulation – 6%-8% water in solid bars compared to 80%-90% in liquid products. Less water allows for concentrated ingredients that provide a creamy lather, hair strengthening, and other functional attributes. Additionally, solid haircare is often made from a syndet base, which does not require preservatives due to its low moisture levels. It is also naturally derived and has a low pH, which is beneficial for your hair and scalp.

Shampoo bars offer unique value through their multifunctional design. Research from Givaudan, indicates that 83% of consumers favor hair products that also feature skincare recognizable ingredients and/or benefits. This signals a growing expectation for innovative solutions across a range of personal care needs. Shampoo bars can be formulated with ingredients that are not only helpful for the hair but also the skin and scalp. When formulated with syndet, these bars maintain a pH closer to that of the skin, resulting in a gentler, more skin-friendly cleansing experience.

Manufacturing Methods: Precision, Quality, and Sustainability in Production

The production of solid shampoo bars relies on three primary manufacturing methods:

1. Hot Pour:
   1. This method begins by melting and blending ingredients before pouring them into molds. Manufacturers can achieve consistent texture, stability, and visual appeal. Hot Pour enables efficient ingredient integration, resulting in a smoother and more uniform bar overall. Since the process involves heat, it creates a denser, longer-lasting bar that maintains its integrity in various environments and takes longer to break down.
   2. The downside of hot pour is that the bars are flat and often have an uneven or wavy finish, depending on how much the formula shrinks. There are also limitations to the shapes of the bars due to the molds and filling process. This method requires a high level of manual labor, including careful demolding of each bar to ensure consistent quality and appearance.

1. Extruded Method: Bradford Specialty
   1. Mild surfactants, including Sodium Cocoyl Isethionate, Sodium Methyl Lauroyl Taurate (SMLT), and or Sodium Coco-Sulfate, combined with conditioners and active ingredients are mixed under high pressure to form a solid bar, then compressed into molds to create a durable, long-lasting bar. Formulations can be made sulfate-free.
   2. A key advantage of the extruded method is its minimal reliance on manual labor, allowing for greater consistency and quality through automation while also supporting cost-efficient production. There are also more options for bar shapes than when using a hot pour method.

1. Compressed Powder:
   1. Ingredients are mixed in the compounder, including oils, color solution, and fragrance. The liquids will then be combined with Sodium Lauryl Sulfate. Other powders and ingredients can be added to enhance the functionality of the bar. Lastly, pressing will begin, which will condense it into its desired shape.
   2. Similar to the extruded method, the bars can be pressed into a broad range of shapes. The production costs are generally somewhere between the extruded and hot-pour options.

Conclusion

The rise of solid shampoo bars reflects a broader shift in personal care: a desire for products that are effective, thoughtfully formulated, and aligned with long-term sustainability goals. By combining concentrated ingredients with reliable manufacturing approaches, solid haircare offers a modern alternative that meets today’s expectations for quality and simplicity. As this category continues to mature, both brands and consumers can expect even greater innovation and refinement in the years ahead.