How to Store Charcoal (and Whether It Goes Bad)

This is one of the few questions in charcoal grilling with a genuinely short answer: charcoal does not go bad, but wet charcoal does not work properly. Everything below follows from that.

It matters more than it sounds. Half the complaints about charcoal being hard to light, burning cool, or refusing to hold temperature come from a bag that has been sitting on a garage floor absorbing moisture since last summer — not from the charcoal itself, and not from the technique.

Why charcoal doesn’t expire

Charcoal is what’s left when wood is heated without enough oxygen to burn: the water and volatile compounds are driven off and you are left with almost pure carbon. Carbon is chemically about as stable as a domestic material gets. It does not oxidize on a shelf, it does not rot, and nothing about it changes over years of dry storage.

This is why you can buy a bag today and finish it in three summers with no difference in performance. It is also why bulk-buying at the end of the season, when charcoal is discounted, is one of the few genuinely free savings in this hobby — there is no downside to owning six bags of briquettes if you have a dry place to put them.

Two exceptions, both about additives rather than the charcoal:

• Match-light / self-lighting briquettes.These are ordinary briquettes pre-soaked in lighter fluid. The fluid evaporates over months, so an old bag lights badly and gives you the worst of both worlds. Use these within a season, or better, don’t buy them — a chimney starter lights plain charcoal faster and without the taste.
• Flavored or infused briquettes.Any added aromatic compound fades. The base fuel is fine; the marketing feature isn’t.

What moisture actually does

Charcoal is extremely porous — that structure is what lets it take in air and burn hot. The same porosity makes it very good at absorbing water vapor out of the air, and a bag left in a humid garage will do exactly that over a season.

A damp bag causes four distinct problems:

• It won’t light. Energy that should be raising the charcoal to ignition temperature is spent boiling off water instead. A chimney that normally takes 15 minutes takes 25, or stalls with half the load unlit.
• It burns cooler. The same energy drain continues through the cook, so your searing temperature never arrives.
• It steams. White vapor off the coals is water, and it makes crisp skin and a dry sear noticeably harder.
• Briquettes can disintegrate. Properly soaked briquettes lose the integrity of their binder and break down into powder, which packs into the gaps between coals and strangles the airflow your fire depends on.

Lump charcoal handles damp better than briquettes because it is solid carbonized wood with no binder to soften — it dries out and burns normally. That is a small point in lump’s favor if your only storage is imperfect. The wider comparison is in lump vs briquettes.

Where to store it

The requirements are simple: dry, off the ground, out of the weather.

Good:a shelf in a garage or shed. A sealed plastic storage bin with a clip-down lid, which is the single best cheap solution — it keeps humidity out, keeps the mess in, and lets you decant a torn bag. A lidded metal can on a covered patio.

Bad: directly on a concrete garage floor. Concrete wicks moisture from the ground and pushes it upward into whatever sits on it, which is why the bottom third of a floor-stored bag is always the worst of the bag. Raise it on a pallet, a plank or a shelf and the problem disappears.

Never: in a living space. Charcoal in storage is inert, but a household should not keep a large quantity of solid fuel indoors, and you do not want a sack of it near a boiler, water heater, tumble dryer or anything with a pilot light or heating element.

One practical note on opened bags: fold the top over and clip it. It costs nothing, keeps the humidity out, and stops the fine charcoal dust at the bottom of the bag from getting everywhere.

How to dry out charcoal that got wet

Entirely recoverable, and worth doing rather than throwing a bag away.

1. Spread it in a single layer. A tarp, an old baking sheet or a patio slab. Piled-up charcoal dries from the outside only.
2. Give it sun and moving air. A warm, breezy day will do most of the work in an afternoon; a genuinely soaked bag wants two or three days.
3. Bring it in overnight, or it will re-absorb the dew you just removed.
4. Test one chimney before committing to a cook. If it lights and ashes over normally, the bag is fine.

Do not try to speed this up in an oven. Charcoal reaching its ignition temperature inside a kitchen appliance is exactly the emergency it sounds like.

The exception is briquettes that were properly submerged rather than damp. If they crumble when you squeeze them, the binder has gone and they will smother your fire with dust. Spread them on a border as a soil amendment and start a new bag.

Storing used charcoal — the one real safety point

This is the part of the page that matters most, because it is where people get hurt.

Leftover charcoal from a cook is worth saving — shut both vents on your grill, starve the fire, and what remains lights again next time. That is a genuine saving, especially on an efficient cooker like a kamado.

But used coals and ash can hold enough heat to reignite for a very long time — well beyond the point where they look and feel cold on the surface. So:

• Leave used charcoal in the grill with the vents shut until you next cook. That is the simplest and safest option.
• If you must empty it, use a metal container with a metal lid, stood on a non-combustible surface, well away from the house, fence and anything that burns. Never a plastic bin, never a paper sack, never a cardboard box.
• Wait at least 48 hours before it goes anywhere near a household bin, or douse it thoroughly with water first and confirm it is cold all the way through.

Ash disposal and the rest of the after-cook routine is covered in how to clean a charcoal grill.

Buying ahead, sensibly

Because charcoal keeps indefinitely, the cheapest way to buy it is in quantity at the end of the season, when retailers are clearing stock. If you have a dry shelf and a sealed bin, there is no reason not to.

Two things worth knowing before you do. Buy the bags you have actually used and liked — a pallet of the wrong charcoal is a long, disappointing summer. And work out roughly how much you get through: our guide to how much charcoal to use gives chimney-by-chimney figures you can multiply by the number of cooks you actually do. Most people overestimate the number and underestimate the bag size.

Which bags are worth stocking up on is the whole of best charcoal briquettes and best lump charcoal.