Stopping it separating
Updated
On this page5
A natural sauce separates. The question is whether you prevent it, slow it, or explain it.
Separation is normal
Water and solids have different densities, so given time the solids settle or the water rises. Nothing has failed. A bottle with a clear layer at the top is a bottle that has been standing still.
Customers do not always read it that way, and a retail shelf is where bottles stand still longest.
What actually holds it together
Particle size, first. A finely blended sauce separates far more slowly than a coarse one, because small particles settle slowly. High-shear blending buys you stability without adding anything.
Viscosity, second. A thicker continuous phase holds particles in suspension. Reduction gets you there without an additive.
Pectin from the peppers themselves does some of this work, and cooking releases it. A sauce cooked properly is more stable than the same ingredients blended raw.
Gums, and using them well
Xanthan is the usual choice and it works at very small percentages. The mistakes are dosing by eye, and adding it dry to the batch where it clumps into gel beads that never disperse.
Hydrate it into a small amount of liquid first, or disperse it into the vortex of a running blender. Weigh it rather than spooning it; the difference between stable and slimy is a fraction of a percent.
It goes on the ingredient statement, and for some buyers a gum is the line between a natural product and a formulated one. That is a positioning decision as much as a technical one.
Or sell the separation
"Shake well, separation is natural" on the label costs nothing and converts a complaint into a signal of authenticity. Plenty of respected sauces do exactly this.
It is the honest option and it is free. Reach for a gum when the sauce needs to survive a distributor's warehouse and a retail shelf, not when it needs to survive a customer's expectations.