Admittedly not the most important question, but...

May 27, 2007 9:49 PM

Best practices for disposing of charcoal after a barbeque?

I've always just dumped the grill out in a corner of the yard, but it occurs to me tonight that this is neither aesthetically pleasing or especially ecologically friendly.

I'm not sure what else there is to do.

posted by BackwardsCity to home & garden (11 comments total)

Burned up charcoal is pretty much just carbon. There's really no environmental issue there.
posted by chrisamiller at 10:15 PM on May 27, 2007

Note that I'm not really going to answer your question; I'm just going to take a long time telling you how to end up with less ash.

The ash is basic, as in, the opposite of acidic, so you're right, it's probably not the best thing for your yard. (In fact, if you really wanted to, you might be able to make soap using it...but read on.)

But...if you use the standard "Kingsford" style charcola briquettes, they are made using a binder that does not burn. Much of the ash you are left with is that binder. (This same binder makes it difficult to use for real soapmaking. So I guess disregard what I said above.)

If you use natural hardwood charcoal, you'll find that you end up with less ash at the end. Note that natural hardwood charcoal burns MUCH hotter due the same lack of binders. It takes some getting used to.
posted by IvyMike at 10:16 PM on May 27, 2007 [2 favorites]

Well, I recall that in the Weber grill instructions (no, I have no excuse for reading them, I just did) I think they recommended storing them in a metal can until they're stone cold, and then disposing of them with your regular household garbage.

If you have rose bushes, and you use natural wood charcoal and you really burn it to ash, you can use it in your garden to raise the soil's pH (if it needs it -- most gardens do but you might want to get yours tested first). Just don't put it on rose bushes, or other acid-loving plants.

Other than that, I can't really think of anything. Compared to other things in your household garbage, it doesn't seem especially toxic, and unless you do a lot of barbecuing, the volume shouldn't be huge. I'd use what you can in the garden and send the rest to the landfill. Just make sure it's completely cold first.
posted by Kadin2048 at 10:18 PM on May 27, 2007

Oh, man ... I should have done a better job proofreading. Just ignore the initial "If you have rose bushes" from my second paragraph, above. It was left over from a different wording of that sentence that I deleted. Just pretend it says:

"If you use natural wood charcoal and really burn it to ash, you can use it in your garden ..."

As others have pointed out, ash is alkaline, so you can use it to raise the pH of acidic soils. But you want to be careful not to make your soil's pH neutral, if you have a lot of plants that prefer acidic soil (roses, some pines...any garden shop can tell you). However, if you have plants that like neutral soil, and you've used a lot of wood-chip mulch in the past (which produces acid as it decomposes), you can sometimes use ash as a soil conditioner to get things back where they ought to be.

Longwinded explanation for a simple question; sorry.
posted by Kadin2048 at 10:25 PM on May 27, 2007

As an aside, I almost burned down my parents house when I was a lad by putting merely warm-to-the-touch half-used coals back in their plastic coal-storage bucket. Half hour later, the whole thing was merrily blazing away, deck was on fire and the siding was going up. Fast work with a hose saved the house.

The yard seems a much better alternative.
posted by maxwelton at 10:57 PM on May 27, 2007

Here's what I do with what builds up in the bottom of our wood-fired space heater:

1. Wait until the heater is absolutely 100% stone cold before doing anything at all with it.

2. Get one of those mesh bags that onions come packed in, and line a bucket with it.

3. Scoop the ashes and charcoal and burnt bones* out of the bottom of the heater into the bag in the bucket.

4. Find some part of the back paddock where it looks like broad-leaf weeds are doing better than the grass, pull the bag out of the bucket, and shake it to sprinkle ash over that area.

5. Once most of what starts shaking out of the bag is dark grey instead of white, take the bag back inside and dump the contents back in the heater to form the base for the next fire.

The presence of broad-leaf weeds in a patch of grass is a pretty good indication that the soil is a little on the acid side there - grasses generally do better in neutral to slightly alkaline soils; and as well as raising the soil pH, wood and bone ash has very useful amounts of potassium and phosphorus, as well as other trace minerals, and does topsoil nothing but good.

Sprinkling ash over a wide area is the key to making it useful. If you put all your ashes in one pile, you end up with a powerfully alkaline lump that nothing will grow in. You'll find that things around the edges of such a pile, though, will grow like crazy.

*We don't eat a huge amount of meat, but such bones as we do get go into the heater, not into the compost. It takes unburnt bones a loooooong time to break down in compost and/or topsoil.
posted by flabdablet at 11:29 PM on May 27, 2007 [1 favorite]

Once upon a time burnt out ashes comprised the bulk of what people threw out - hence "dustbin" and "dustman" in the UK. This was in the days of metal rather than plastic bins so fewer problems with fires. I would say wait till its cool and chuck it out - old school style.
posted by rongorongo at 3:59 AM on May 28, 2007

The chunks of remaining charcoal can be used in the next barbecue.
posted by theora55 at 7:45 AM on May 28, 2007

Ash also works as a good deterent to slugs & snails (they hate crawling over it) - even better when mixed with sand. As others have said, some plants don't like the alkalinity, but a light sprinkling of ash/sand mixture around seedlings and other slug/snail magnets works a treat (although it needs replacing after each rainfall).
posted by dogsbody at 7:56 AM on May 28, 2007

corner of your yard is the best answer
posted by caddis at 8:21 AM on May 28, 2007

Reuse the half burnt charcoal. If your grill can be fairly air-tight, just closing it up will cause the coals to go out. Otherwise you can dump the coals into a a metal container with a well fitting lid (such as a dutch oven) and they will extinguish.

The next day or next time you use the grill you can fish out the big chunks or pour everything through some metal mesh.
posted by MonkeySaltedNuts at 12:42 PM on May 28, 2007