Black walnut

[WDH]

Steaming, yes, but steaming also dulls the natural colors in the heartwood from what I have seen. 

[POSTON WIDEHEAD]

I have customers that only want air dried Walnut and will absolutely turn away from kiln dried Walnut.

[YellowHammer]

I have customers that only want air dried Walnut and will absolutely turn away from kiln dried Walnut.

I have seen this also, and that's one of the advantageous of a low temperature dehumidification kiln as opposed to a steam kiln.  The DH kiln, if operated correctly, will preserve the rich colors to the point that even air dried only folks will snap the lumber up. 

I get a lot of my lumber planed at a professional wood and millwright shop down the road that purchases many, many thousands of Bdft of steam kiln dried lumber of most commercial species from all over the country.  Many times the owners and I have compared the properties of my DH wood to theirs, side by side, and there is a significant difference in some wood species.  The steam kilned dried walnut will be duller and grayer, losing much of its highlights, cherry will have more brown and less red, and even sassafras shows almost a complete loss of chatoyance, which is one of the major reasons people buy sassafras. 

When I buy walnut logs, one of the things that really affects yield is the thickness of the sap ring.    Since the logs are Doyle scaled (around here) then the thicker the sap ring, the less yield per log of heartwood because I'm buying and paying on log diameter, not heartwood diameter.  So thats why I wish I could make a mostly sapwood board behave and not curve so badly when I dry it because it's costing me money, and I hate throwing money into the burn pile.  And walnut ain't a cheap log to be wasting wood.