I hand-carved my first Kuksa a month ago from half an ash log. I worked with semi-dry wood (definitely not green, but still wet). I used axe, Japanese gouge and knife and all went well. The bowl is not too thick either.
So I let it dry in a plastic bag opened in the bowl and after some (short) drying I put linseed oil on it and let it dry more. I was quite surprised because it was absorbing so much linseed oil. A bit like a sponge... After two weeks of drying and the final application of a mixture of beeswax with linseed oil and some more drying I tested it with some warm tea.
To my disappointment I got a lot of linseed oil floating in my bowl. Then I let the tea in the bowl for some time, to see how it holds. In very little time tea began to ooze from the pores on the outside of the bowl in the faces that were cut across the grain. Then the bottom which was getting wet from this has split.
So I guess my mistake has been to not let the wood dry out completely before oiling and that the oil somehow has caused the wood to contract, somehow keeping the pores open.
Am I guessing right? Or is the ash really spongy like this and not suitable for bowls? Or have I overlooked something. Sorry I'm only starting with bowl carving...
I would like to add that I haven't got this issue with a well-dried beech bowl.