I use Higgins drawing ink and 99% alcohol as a stain. It is available in Europe in a variety of useful colours like black, umber and sienna (I saw the ink in Germany) and the Higgins dye won't fade with time. Other alcohol will work, but the more water the greater the risk of warping.
Always stain the wood first if possible, as the glue seals it and can result in a splotchy finish.