A lower fill for back sleepers
You need a lower fill than a side sleeper: enough hull to fill the curve behind your neck, and no more, so your head never tips forward. Most standard pillows arrive fuller than that. The usual job is taking hulls out.
In short: Run a lower fill than a side sleeper, remove hulls until your chin sits level, and keep it pure hull unless weight bothers you.
The fill, specified
| What | Specification | Source |
|---|---|---|
| Target height, lying on it | About 10 to 11 cm, roughly 4 inches | A 2015 X-ray study judged 10 cm the most suitable height for the neck's normal curve. In a 2016 pressure study, neck pressure at 110 mm, the lowest of four heights tested, was 65% lower than at 170 mm |
| Fill weight for a standard 20 by 26 inch pillow | 7 to 9 lb | A seller's fill guide puts a standard pillow at around 7 to 9 lb, and a fully filled one weighs about 12 to 13 lb |
| Hull volume, in litres | None of the sources read gives a figure in litres | One seller gives about 200 cubic inches of hulls per pound, and calls that a rough estimate |
| Polished or unpolished hulls | Unpolished suits most answers; if the sound worries you, read about polished first | No figure. See polished versus unpolished hulls |
| Pure hull or hull with wool | Pure hull; a wool layer is worth reading about only if a lighter pillow matters more | No figure |
Why this fill follows from your answers
On the back, the pillow only has to fill the hollow between neck and mattress. There is no shoulder width to bridge. That is why the target sits near 10 cm, the height a 2015 X-ray study judged most suitable for the neck's normal curve. Back sleeping also comes out lower than any side position in the height guide by sleep position. In that study, as pillow height rose, both the slope at the top of the spine and the curve of the neck increased. Too much hull pushes the chin toward the chest.
Hulls hold whatever shape they are pushed into. That is the firm, mouldable feel you asked for, and no other fill gives it. A lower fill sits lower, but the hulls still hold their shape. For more give, lay a thin flat pillow or a folded towel on top.
The weight and sound answers set the last two rows. For anyone who reshapes the pillow at night, a lower fill moves more easily under the hand. If you would rather it were light, this fill already helps. A fully filled standard pillow weighs 12 to 13 lb, against the 7 to 9 lb in a seller's fill guide. How much a buckwheat pillow weighs explains why the weight is part of how it works. If you were unsure about the crunch, read polished versus unpolished hulls before settling on either. Why buckwheat pillows are noisy covers who never gets used to it.
What changes it
The mattress moves the number most. On a soft or pillow-top mattress your body sinks lower, which shrinks the gap the pillow has to fill. There, start near the bottom of the 7 to 9 lb range in a seller's fill guide. On a firm bed the body stays higher, so start near the top of that range. On a medium bed, start in between.
What to check on your own bed
Lie on your back for a few minutes with your usual pillowcase on. The chin should be neither clearly raised nor dropped toward the chest, the landmark a pillow fitter's guide gives for lying face up. If it tucks down, take out a cupful of hulls and lie down again. If the head tips back, add some. Change a little at a time. By one seller's estimate each pound is about 200 cubic inches, so a cupful shifts the height only slightly. Give each change a few nights before judging it. Keep spare hulls sealed and dry; the moisture guide explains why that matters.