How big a batch to make

Batch size in this category is pulled in two directions at once: testing costs push it up, and uniformity and shelf life push it down.

Three constraints, not one

Blender capacity, which is the obvious one and rarely the binding one.

Uniformity, because blend time and mixing energy do not scale with volume and a larger batch is not simply more of a smaller one.

Shelf life, because a batch larger than your sell-through spends its life aging on your own shelf while its declared potency runs down.

Blending does not scale linearly

Fill level changes how material tumbles, which changes the mixing action. Discharge takes longer, during which segregation is already happening. And a deeper container percolates more.

So a doubled batch needs its blend time re-established by sampling, not doubled by arithmetic. And it needs sampling from more points, because there is more batch in which to be non-uniform.

Shelf life and the testing cost

The pressure to batch large is real: identity testing, potency assay and blend uniformity work are per batch or per formula, so a bigger batch spreads them further.

Against that, a supplement powder has a declared shelf life and a potency that declines within it. Making a year's supply means selling most of it in the back half of its life, closer to the point where overage stops covering decline.

The balance point is sell-through: batch what you will move within a comfortable fraction of the declared life.

Choosing, and re-qualifying

Write the batch size into the master record alongside the formula and process. It is a specification, not a convenience.

And treat a change in it as a change requiring re-qualification: new blend time, new sampling, and a potency check. A batch size changed quietly is how a product stops matching what was tested.

References