Collecting Ash for Glazes

It’s a few days since the fire died down, I’ve been out there in the paddock collecting the ash for use in glazes. If I try to get there and dig up the ash before it is mostly cooled. I can get burnt, so I must be careful. I wear my oldest thick soled boots, as the ash and charcoal from the burn pile holds its heat in the ground for ages. I have melted the soles of my boots in the past, going in too soon.

If I wait for too long for it to cool, then there may be a strong wind, and that will simply blow away the finest particles of ash, scattering them all around the grassed area. Worse still, is rain, as that will dissolve and rinse away the solubles in the ash. Its the solubles that are the fluxes, and these are so important in ash. They are what makes ash melt and be so useful in glazes. It’s also important to me to be as self-reliant as possible, so I don’t want to waste this important potential resource. Doubly so in this case, as there are no more pine trees left on our land. The bush fire here was so hot and intense, that it killed every single one of them, and I haven’t seen any seedlings germinating out of the ashes in any of the paddocks. It’s the end of an era here.

In fact we did have a little shower of rain on the 2nd night after the fire was finished, so some of the usefulness of the exercise will have been lost. I won’t know how much was lost, until I get it all sieved, processed and tested to find out. I suspect that it will be too far gone to be useful to me as a glaze ingredient, but that wont stop me processing it to find out. We only have a burn pile like this once in a decade where we burn off stumps and big logs. It was the big pine logs that made this burn pile ash so attractive, as pine ash is very different to the hard wood eucalypt ash that we collect from the slow combustion kitchen wood fired stove every week. The slow combustion stove works best on hard wood fuel, and that is what we have plenty of here. Now especially since the fire leaving so many dead gum trees to deal with.

The ash from our Caribbean pine trees here is clearer, paler and more fluid than the ash from our local stringyback and bloodwood eucalypts. Their ash melts to a matt yellow/mustard colour, and is rather more firm, being lower in the alkalis than the pine. They are both good, just different.

I set about digging into the pile of still warm ash and charcoal and found it littered with calcined lumps of subsoil from the tree roots and stumps. Not a good sign. I was hoping for a deeper cover of fine white ash before hitting the heavier stuff. Pity!

I started by sieving the ash through the first 6mm screen to get rid of the big chunks of soil and charcoal, then down through the next 2.5mm screen.

I filled a large metal garbage bin with this first pass. I use a very old and slightly ruined bin for this, as if the ash turns out to be still a bit too hot, it will melt a plastic bin, or burn the zinc off a good bin.

As the burnt pile of ash decreases, the pile of discarded sievings increases.

The second pass is through a finer sieve. It can’t be too fine at this stage as ash is very sticky, and will clog up a very fine sieve. I use a 40# lawn or about half a millimetre, as the ash will pass through this fairly easily. It’s a stainless steel sieve that went through the fire in one of the sheds that burnt down, but not too hot, as the fine mesh didn’t crumble. All my other sieves that were burnt, were completely ruined.

I shovel the coarse ash out of the first bin and back through the fine mesh into the second bin. 1 1/4 bins of coarse ash becomes 3/4 of a bin of fine ash. The discard pile grows as the fine detritus mounts up on top.

Mission accomplished for the time being. The next step is to wash the ash with water to get it to pass through a 100# sieve. But that is for another day. At least this garbage can full of dry ash will keep indefinitely in the storage room, safe from the vagaries of the weather.

All packed up and ready to go. This much ash will last a few years of glaze making.

Nothing is perfect, nothing is ever finished and nothing lasts.