Article by: Perry Romanowski
When you create a formula in the lab it’s rather easy to create batches that are consistently the same in terms of their physical and chemical characteristics. This is because you use sensitive balances, you work with smaller amount and you are not typically under pressure to get something made on a specific schedule. These same conditions are not true of production and for these reasons (and others) you need to set specifications for your finished formulas.
What are cosmetic specifications?
Specifications are a range of values assigned to a formula which dictate the physical and chemical characteristics of any batch that are acceptable for a quality product. If some characteristic of a batch is found to be outside of the specifications the batch is either adjusted or discarded before it can be sold. In this way, specification ensure that every consumer will have a consistent experience every time they use the product.
Who sets specifications?
The specifications are initially set by the product development team.Traditionally, R&D takes the leading role in this process but they also get input from the marketing and market research departments for factors that will affect consumers. As the lead product formulator, you are ultimately responsible for setting specifications.
The product specifications for any cosmetic formula will vary depending on the type of product it is, but there are some commonalities. For example, all products should have an appearance specification. When the batch is done it should be checked for color, clarity, or any other unique appearance that the formula is supposed to have. If your product is a blue body wash but the final batch appears green, it would fail the specification test. Another common specification (or spec) would be odor. Product batches should always be checked against an odor standard to ensure it has the proper odor.
Other key characteristics that get listed in the specifications would include
- pH – A range should be set for every aqueous based formula
- Viscosity – A range should be set for any liquid formula. Also, the test should be done using a standard spindle and speed.
Of course there can be other specifications that are measured including product performance tests, penetration tests, moisture % tests, and more.
Ideally, you’ll set specifications for the least amount of testing required to ensure that the product is consistent. Production people are under a time crunch and often don’t want to wait for intensive testing before releasing the final batch.
Who tests the product?
Normally, the specification testing is done by the Quality Control group at your company. In this way there is an independent verification of the quality of the final product. The production group is under pressure to release as many batches as they can so if they were responsible for the testing, they might pass batches which are borderline.
What happens when a product is out of spec?
Since there are numerous reasons a product could have characteristics outside of specifications there are numerous answers to this question. Sometimes adjustments are made. For example, if the pH is too low or high and acid or base is added to adjust the pH. If the viscosity is off sometimes the batch is reprocessed (heated, mixed and cooled again) or an ingredient known to increase or decrease the batch is added.
If something like the color or odor is off often the batch will be blended off with another batch in a small enough proportion that the mistake isn’t detectable.
But sometimes, and production people hate when this happens, a batch is too far out of spec to be saved and it has to be discarded.
Specifications are an important aspect of formulating and as a cosmetic chemist you need to be familiar with why they are used and how you set them. In a future post we’ll look at how to set them.