Straining, and whether to
Updated
Straining is a flavor and appearance decision that producers often make by default rather than on purpose.
What straining removes
Seed fragments, skin, and coarse pepper particle. That gives a smoother mouthfeel, a cleaner look in a clear bottle, and a sauce that flows through a narrow orifice without blocking it.
It also removes some of the sediment that would otherwise settle in the bottle and generate the question about whether the product has gone off.
What it costs you
Yield, and it is not trivial. Depending on mesh and pepper, straining can take a meaningful fraction of the batch out as pulp, and that pulp is the most concentrated part of what you made.
Body goes with it. A strained sauce is thinner and often needs reduction or a thickener to get back to the viscosity it had, which puts the cooking time back in.
And the pulp is not waste. Dried and ground it is a seasoning; folded into a second product it is a paste. Throwing it away is throwing away the part with the most flavor per gram.
Mesh and method
Coarse mesh takes seeds and leaves body. Fine mesh takes body too. Choose the mesh against the bottle: if the sauce goes through an orifice reducer, the strainer needs to be finer than the hole.
Pressing through a strainer recovers yield and pushes fine particle back into the sauce, which partly defeats the purpose. Let it drain if you want clarity, press if you want yield.
The middle option
Strain part of the batch and recombine. You get a smoother sauce than unstrained and better yield than fully strained, and the ratio is a dial you can set.
Whatever you choose, write it into the recipe as a step with a mesh size. It is one of the largest determinants of the finished product and it is usually the least documented thing in a producer's process.