I’m in the middle of making 6 greenwood chairs using cleft oak shaved to shape along the grain with a drawknife and spokeshave, etc..

The rungs are made first, with round tennons turned on each end.  When dry, they are inserted into round tennons made in only partially dried legs.  Leg shrinkage subsequently exerts a vice-like grip on the tennons so the need for glue is obviated.

The first chairs I made were in ash, over 1 week.  My tutor dried the ash rungs rapidly in his oven, so the project could be finished in 1 week.  Ash is OK with this treatment but the oak I am using now is not.  It would split reet quick if I tried to oven it, or even left it in the sun.

I don’t want to have to wait weeks for the oak rungs to dry out slowly, so I considered helping the process along using steam. 

The chair legs and slats are steamed to bend them.  Paradoxically, when they emerge from the steamer and have cooled, they have reduced in moisture content from their 40%-ish at green to around 20%.  Strange.  But true.

I hope to steam dry the rungs and avoid splitting.  Steaming the back slats prior to bending them has certainly not caused them to split.

I’ve searched the Web a bit but can’t readily find out why steamed wood loses rather than gains moisture content.  It seems counter intuitive. 

When oak (and ash) is steamed, there is a delicious smell of Xmas pud from the steamer.  Perhaps the steam is leaching out the sugars in the green wood and, by doing so, immediately reducing its water-retaining ability?  In a former life, I was a bit of a racing cyclist, and dietry wisdom advised one to  avoid energy intake via sugary choc bars, as sugar apparently attracts 2 1/2 X its own weight in water – sucked out of the needy cyclists’ bloodstream straight into his digestive system. (But I digress).

Anyone have wisdom and knowledge on this phenomenon?  (Drying via steam, I mean, not cyclists diet). Can one steam wood to as low as 10% moisture content, or is this not physically possible?