Start by looking at the space you already have

Most British homes come with a ready-made pantry and don't know it. That narrow alcove beside the chimney breast, the dead space at the end of a galley kitchen, the gap between the fridge and the back door — any of these will hold a sturdy shelf and, once it's up, it will quietly become the most useful metre in the house.

Dry goods want three things: cool, dark and dry. An alcove away from the cooker and out of direct sun is ideal. A shelf above a radiator is not, and neither is the wall behind a boiling kettle. Flour, rice and pulses keep for months in the right spot and go claggy or weevilly in the wrong one, so choose the position before you choose the timber.

Have a proper look at what's already there. Skirting boards, a stopcock, a spur of cable running down from a socket, pipework for the radiator — all of it will interfere with a flat shelf and a straight bracket. Better to find out now with a torch and a tape measure than halfway through drilling.

Measure the alcove honestly

Old walls are rarely square, and alcoves are rarely parallel. Measure the width at the top, the middle and the bottom, then work to the narrowest figure. A shelf cut to the widest measurement simply will not go in.

• Width: three readings, use the smallest, then subtract 5mm for wiggle room.
• Depth: 250–300mm suits most jars. Deeper than 350mm and things vanish to the back.
• Height: leave at least 350mm of clearance above the shelf so you can lift a full jar down without clouting the one behind it.
• Obstacles: note the height of any socket, pipe or uneven plaster you'll need to bridge.

If the wall is plasterboard, find out what's behind it. A detector that traces cables, pipes and timber will tell you where the studs run. Fixing a loaded food shelf into plasterboard alone is asking for trouble; into brick, block or a timber stud it will hold for decades.

Timber, brackets and the right fixings

For a shelf carrying jars, thickness matters more than looks. Go for 25mm solid pine or birch plywood. Anything under 18mm will bow in the middle once the flour goes on.

Brackets should be steel, at least 25mm wide, and deep enough to support two-thirds of the shelf's depth. As a rule of thumb, use one bracket every 600mm, with a minimum of two. A 1200mm shelf wants three.

Fixings depend entirely on the wall:

• Solid brick or block: 6mm masonry bit, brown wall plugs, 50mm × 5mm screws. Drill 10mm deeper than the plug.
• Timber studs: 50mm wood screws straight into the stud. Mark the stud centres in pencil on the wall first.
• Plasterboard with no stud where you need one: use proper hollow-wall anchors rated for the load, and keep the heaviest jars directly over the brackets.

Fitting it so it never sags

Mark a level line across the alcove with a spirit level, then offer each bracket up and mark the holes through the metal. Check the line sits flat against the wall as well as level along it — wonky plaster can pull a bracket off true, and a thin packer behind the bracket sorts it.

Drill, plug and screw the brackets to the wall first. Only then lay the shelf on top and fix it down. Pilot-hole every screw hole in the timber, countersink the heads so they sit flush, and if your brackets have a front hole, screw up into the underside of the shelf as well. That single screw stops the shelf tipping when someone leans on the front edge.

When you load it, put the flour and the big bags of rice directly above the brackets, where the shelf is stiffest, and lighter items like herbs, baking powder and dried fruit in between. Spread the weight evenly and the shelf will stay flat for years.

Jars, labels and a layout that works

Decanting into glass is the whole point. You can see what you've got, insects can't chew through it, and nothing smells of the bag it came in.

• 1kg of plain flour needs roughly a 2-litre jar.
• 1kg of rice or 750g of red lentils fits comfortably in 1 litre.
• Clip-top jars with rubber gaskets keep contents freshest; screw-top jars are easier to stack and clean.

Label everything — contents and the date you filled it — and use a funnel when decanting to save sweeping the worktop afterwards. Group by use: baking together, rice and pulses together, spices and small jars at eye level where you can reach them. Oldest jars go at the front, and the whole shelf gets a glance before you shop, which is half the reason for having it.

Keeping the shelf honest

A pantry shelf only earns its keep if it stays tidy. Once a month, wipe the shelf, check the seals on the jars and shuffle anything that's been sitting untouched to the front. White flour keeps for six to twelve months; wholemeal, nuts and stoneground flours go rancid sooner because of the oils, so buy those in smaller quantities and use them first.

If a jar has been open and half-used for a year, tip it into the bin without guilt and start again. There's a quiet satisfaction in a shelf like this — a row of labelled jars, everything reachable, nothing hiding at the back turning into a science experiment. It costs an afternoon and a length of timber, and it makes the kitchen feel like somewhere that's been properly thought about.