What is 'spalted' wood?

The word 'spalted' is one you will see fairly often here on Woodsmithery, usually - but not always - associated with beech.

It's important to be delicate when explaining to a customer what this means though, because the bottom line is that spalted wood is simply starting to... well, let me explain.

Beech wood grainThe timber in a healthy beech tree is, to be frank, a bit dull.

It's pinkish and plain, and the grain doesn't really do much other than go from A to B with little in the way of deviation or interest. Don't get me wrong, it has other qualities like strength and... er... ummm... other stuff, but in the looks department it's just nothing to write home about. It takes colour well, though.

spalted beech

But if you take that boring old wood and leave it on the ground for a while where it's damp and maybe a bit icky, it will begin to develop interesting patterns in the very early stages of its inevitable decay, caused by microscopic fungi starting to break down the fibres. As the fungi tries to take hold it will follow various paths of least resistance, creating dark lines and changing the colours of random areas of the wood. This is known as spalting.

If this is left to continue unchecked, over time the decay will get a good foothold, making the wood soft and 'punky' - a bit crumbly here and there - until it eventually rots and falls apart. But if you catch it just right you can find some astonishing patterns when it's on the lathe and if the wood is dry and sealed then the fungi that caused the spalting in the first place is completely dead and harmless.

Other woods develop spalting to varying degrees and with differing results, but spalted beech is one of the most common here in the UK which is great news because it is also one of the most beautiful and sought-after by woodturners everywhere.