Graining
Updated
A balm that goes gritty after a week is the defect that ends most first attempts at a shea formula, and it is entirely a process problem.
What it feels like
Sandy. A fine grain that the customer reads as the product having gone off or having something in it.
It shows up days or weeks after pouring, which is what makes it so frustrating: the batch passed inspection, shipped, and failed at the customer.
The cause
Butters like shea contain fractions that solidify at different temperatures. Cool slowly, and the high-melting fraction crystallizes first and grows into large crystals while the rest is still liquid. Those crystals are the grain.
Two process faults produce it. Not melting high enough, so some crystal structure survives and seeds the rest. Cooling slowly, which gives the crystals time to grow.
Preventing it
Take the melt well above full melt, high enough that nothing is left of the previous crystal structure. Hold it there briefly rather than just touching the temperature.
Then cool fast. Pour promptly, and set the filled tubes somewhere cold rather than leaving them on a warm bench.
Do not hold a finished melt warm for an hour while you do something else. That is a common cause and it looks like patience.
Or use a butter that grains less: refined shea, mango, kokum.
It cannot be fixed in the tube
Once grained, the balm has to be remelted properly and repoured. There is no resting it out.
Which means graining found after filling is a full batch loss of labor and tubes, and is the strongest argument in this craft for pouring a few test tubes and waiting a week before committing a production run to a new butter or a new supplier lot.