Your surface is sanded. Raking light says it's clean. Your hand says it's smooth. Both are telling you the truth, mostly.
If you're reaching for an oil-based finish, solvent lacquer, or hardwax oil, keep reaching. This step isn't for you. Those finishes don't raise the grain. Move on.
If you're reaching for anything water-based, stop. Put the can down. You have one more step, and skipping it will cost you a coat and a sanding session later.
What's Actually Happening
When you sanded that surface smooth, you didn't just cut wood fibre. You compressed some of it. Bent it flat. Under raking light and under your hand, it feels gone. It's not. It's lying down because it's dry.
Water stands it back up. The first coat of a waterborne poly or water-based lacquer carries enough moisture to swell those compressed fibres upright. The surface that felt like glass ten minutes ago now feels like fine stubble. That's grain raise. Not a product defect. Not a species problem. Physics.
The conventional fix is to sand between the first and second coats with fine paper. This works, but you're sanding through cured finish on the high points and leaving it thick in the low spots. You can do better.
Raise It Yourself, Before the Finish
The idea is simple: do the raising now, when fixing it costs a damp cloth and thirty seconds of sanding. Not under the first coat, when fixing it costs a whole coat and careful re-sanding.
Take a clean, lint-free cloth. Dampen it. Not wet. Damp. You want enough moisture to wake up those fibres, not enough to move the board. Wipe along the grain, full coverage, every surface that will receive finish. The wood should darken slightly at the surface. If it feels wet to the touch, you used too much.
Set the piece aside. In a warm, dry interior shop, twenty to thirty minutes and it's done. In a humid coastal shop, plan for an hour. The test: run your hand across it. No cool patches, no dampness. Just that fine stubble.
Feel it? Good. That's everything you're about to remove.
The Sand-Back
This is not re-sanding the surface. You already did that in the sanding progression. You're removing fuzz.
Use the same grit you closed with. Finished at 220, sand back at 220. Finished at 180 on hard maple, sand back at 180. The logic: the scratch pattern already on the surface is at that grit. Matching it means you remove the raised fibre without introducing coarser marks.
Light pressure. Full-length passes along the grain. One pass is usually enough. Two if you feel resistance. You're not trying to feel a dramatic surface change. When it feels exactly like it did after your final sanding pass, you're done. That's correct.
One thing: this step eats sandpaper. The raised fibres load the abrasive fast, and a loaded sheet burnishes instead of cutting. If you're covering a lot of surface, fold a fresh partial sheet and replace when the cut feeling goes.
Tack cloth. Move on.
The Shellac Question
If you're applying a dewaxed shellac wash coat for blotch control on cherry, maple, or alder, the sequence matters: raise the grain first, sand back, then apply the shellac, then sand lightly at 320 before your water-based finish or stain.
Don't reverse it. Raising the grain after the shellac wash coat pulls fibres up through that thin film and breaks the seal. A broken wash coat defeats the whole purpose.
The shellac itself may raise the grain slightly, but the alcohol carrier evaporates faster than water, so it's mild. That 320-grit pass after shellac handles it. If you've already done the damp-wipe raise before the shellac, the 320 pass is cleanup, not structural work.
Why Bother
The grain raise is going to happen. The moisture in a water-based finish guarantees it. The only question is whether it happens on your terms, with a cloth and some sandpaper, before the finish goes on. Or on the first coat's terms, under the finish, when the fix is slower and uglier.
Twenty minutes and a light sanding pass. That's the whole cost. The surface you send into the first coat is the surface that was actually there all along. No surprises.