shot to fame

[elfbert]

So the answer to yesterday's question is that iron reacts with tannins to form a dark black substance - so Oak, being rich in tannins, plus iron, plus the moisture in the tree would stain the wood dark black. They actually use tannins and iron sulfate to make a sort of ink. So whilst you all guessed it would mark the wood, none of you got the

Comments

[nx_01hreod]

I should have realised about the tannins. I use oak - shavings soaked for ages in water - to make tannin mordant for dyeing. And iron too is a mordant, used to sadden colours. Oak tannin with an iron overbath will give black. Easy to be wise know you've told me the answer. XD