Storing atta through a Lahore summer.

What actually spoils atta in this climate

There are two separate failures and they look different. The first is rancidity. Whole-grain atta carries the wheat germ and the germ carries oil, and heat drives that oil towards a sharp, crayon-like smell. A kitchen shelf above a stove can run many degrees hotter than the room it is in, so where the container sits matters as much as what the container is.

The second is moisture. Flour is hygroscopic — it pulls water out of the air — and Lahore's July and August air has plenty to give. Damp flour cakes into hard lumps, ferments to a sour smell, and becomes a comfortable place for mould and insects. This is why a bag that was fine in April can be unusable by the end of monsoon without ever having been badly handled. Both failures speed each other up, which is why summer is the season worth changing habits for.

The container, and why the paper sack is not one

A sack rolled shut at the top and clipped is not a seal. It breathes, and in this climate breathing is exactly the problem. Move the flour into something with a real closure: a gasketed plastic tub, a steel canister with a tight-fitting lid, or a wide-mouthed jar you can get a scoop into without decanting again and again.

One habit worth breaking is topping up. Pouring a new bag on top of the last few inches of an old one mixes ageing, possibly rancid flour and any insect eggs it is carrying straight into the fresh stock, and the container never gets cleaned. Finish a container, wash it, dry it completely — residual damp is worse than what you washed out — and only then refill.

• Fill the container reasonably full. Less headspace means less trapped air sitting against the flour.
• Write the pack date on a strip of tape on the lid. Once the sack is gone, that is the only record you have.
• Keep separate containers for whole-grain and refined grades. They keep for different lengths of time and mixing them hides which one has turned.
• Let a warm or freshly milled bag cool to room temperature before sealing it, or the moisture it gives off condenses inside the lid.

Where in the house to keep it

Cool, dark and dry, in that order of importance. The worst spots in most Lahore kitchens are the shelf directly above or beside the stove, the top of the fridge where the compressor exhausts warm air, and any cupboard on an outside wall that catches afternoon sun. The best is usually a low interior cupboard, on a shelf rather than on the floor, away from the wall so air can move behind the container.

Keep flour away from strong smells too. The fat in whole-grain atta takes up odours readily, so a container standing next to detergent, a phenyl bottle or an open masala dabba will end up tasting of its neighbours. Small quantities keep very well in the freezer; the trick is to let a frozen pack come back to room temperature while still sealed, so the condensation forms on the outside of the packet instead of in the flour.

Weevils: where they come from and how to stop them

The small dark beetles people call ghun or susri almost never march in from your kitchen floor. They arrive inside the grain. Eggs are laid in the wheat before or during storage, survive milling in the odd intact fragment, and hatch weeks later in a warm dark container that is, from their point of view, ideal. That is why a sealed jar can produce insects on its own, and why sealing alone is not a complete answer.

The one intervention that reliably works is cold. Put a newly bought pack in the freezer for three or four days before it goes into the storage container; that kills eggs and larvae as well as adults. The traditional deterrents — whole cloves, bay leaves, dried red chillies, neem leaves tucked into the container — discourage adults from settling and are worth doing, but they do not kill what is already inside the flour. Space containers apart on the shelf rather than packing them together, and remember that an infestation in the suji jar will find the atta next to it.

You found weevils. What now?

First judge the flour, not the insects. If you see a few adults, the flour is loose and dry, and it still smells sweet, sieving it through a fine chalni and using it up quickly is reasonable. If the atta has webbing running through it, clumps stuck together, a fine powdery dust at the bottom of the container, or any sour or musty smell, sieving achieves nothing — the smell and the debris are through the whole batch. Discard it.

Then deal with the container and the shelf, because that is where a repeat comes from. Empty the container completely, wash it in hot water, and dry it in the sun until there is no trace of damp. Wipe out the cupboard, paying attention to corners, shelf lips and the gap behind, and check every other jar on that shelf: rice, suji, dalia and daal are all as attractive to the same insects as atta is.

Buy to a horizon, not to a habit

The storage problem is much smaller if the bag is smaller. We pack atta from one kilo up to fifty, and the right size is not a fixed household number — it is whatever you will finish while it still smells sweet, which changes with the weather. A bulk sack is sensible from about November, when a cool store room does half the work for you. Through the hot and humid months, buying more often in smaller packs means a few extra trips and saves the flour.

Refined grades are more forgiving through summer for one reason only: the germ has been sifted out, so there is much less oil to turn. If you keep both, work through the whole-grain flour first.