Manufacturing cosmetics: how to manage scale-up and limit waste

Scale up steps in cosmetic manufacture

When manufacturing cosmetics, taking scale up steps are essential. The methods and equipment you used to make that 100g R&D sample will vary dramatically in size and time with a 100kg or even 20kg batch. It is essential to follow scale up steps to test the changes in mixing speeds and times, as well as the equipment used, and the batches of materials used, to rule out any variables that may turn into a ruined batch.

Let’s face it, no-one wants to waste a 100kg batch.

So, how do you conduct proper scale up? These are the steps you should follow:

• First, make sure you have at least some preliminary stability data on your 100g lab sample.
• We recommend at least two weeks freeze/thaw cycles and extreme (+20°C ) accelerated temperature testing.
• If you are not familiar with the concepts or terms associated with stability testing, please watch our video on cosmetic stability testing, learn the essentials with our stability testing for small brands workshops, or learn stability testing to a professional level with our Certificate in Cosmetic Quality and Stability.
• Once your small lab sample has passed, you would prepare a large lab sample; typically 1-2kg in size, using large lab equipment. This equipment would likely differ to what you used to make 100g; even if the equipment doesn’t differ, the times taken to heat, cool and stir will differ, and this helps test the method and times of processing at this stage. You may also find you need to use cosmetic raw materials from different batches albeit the same supplier – this starts to test the materials too. If there are issues at this stage, they are usually corrected by reconsidering the method and/or equipment.
• Once that large lab batch has passed quality checks, you are ready to proceed to the pilot batch. The pilot batch should be 10-20kg, and should use the same sort of equipment, although on a much smaller scale, as will be used for the larger production batch. For some small brands, your pilot batch may be your main batch, and that is okay too. At this stage, you would be ordering larger batches of raw materials from suppliers, which will check to see if different batches of the same materials impact your finished product; but you are mostly testing the significant change to equipment. You are also again testing the method with even longer processing and mixing times, using different equipment.
• The pilot batch is the step where most issues can happen, largely due to the time differences required in processing, as well as the sometimes dramatic differences in equipment used. If something goes wrong at this stage, you can usually identify the issue easily (most commonly the equipment, but may also be the heating/cooling or mixing times). In many cases, this size of batch is still able to be saved – by either reheating, mixing using a different shear or other small interventions. If it can’t be saved, it is still better than wasting 100kg of product.
• Once the pilot batch has passed quality checks, you can proceed to 100 – 200kg batches or more.

Even the most theoretically robust cosmetic formulas should have all scale-up steps incorporated because what works in 100g, or on paper, may not always work when it is transferred to a larger production batch.

How to limit waste in cosmetic manufacture

A common question we get asked is: how much waste is tolerable in cosmetic manufacture?

The short answer is 2%w/w or less. This might sound unfeasible, but a lot of this is product that gets caught in short tubes or parts of processing and filling equipment. You actually need to make sure you limit any other losses to stay within this 2%w/w limit. These are unacceptable losses:

• Dispensing materials – ensure you use scrapers or suitable dispensing equipment to get every last bit of dispensed material into the batch. You might miss a drop or two but transfer as much of the dispensed cosmetic materials into the batch otherwise you can get batch to batch variation in the finished product. You also don’t want to wash straight raw materials down a sink!
• Evaporation – we hear of companies weighing their equipment to replace evaporation losses, but this is not a solution. Stop evaporation in the first place! Adding lost water back at the end can mean unpreserved water or impact stability. Instead, take steps to avoid evaporation with minimum air time (this also reduces microbial risk) and vats with small openings to add materials or check quality (rather than needing to remove a whole lid).
• Inappropriate equipment – if your equipment is not fit for purpose, you could be losing product when transferring from the production to filling stage, or even during filling. You will invariably lose some product caught in production equipment but you need to validate your machinery to limit this as much as possible. Make sure you can retrieve and even manually fill what you can from equipment rather than make the cleaning process more expensive and arduous than it already is!

Our manufacturing cosmetics workshop series is designed to help you choose the right equipment and use the right documents and procedures to minimize quality risks and maximise product returns, all on a tight budget specifically for small brands. If you’ve found this blog helpful you stand to gain so much more from our manufacturing cosmetics for small brands workshop series.

Good luck, and remember there is nothing more satisfying than watching raw materials transform into a beautiful finished product.

Happy formulating!