Nice experiment with the Gamble oak, and those ribs sure do look good!
I think you'd have to be careful with black walnut. As I recall, it has a reputation for slightly bitter, acrid smoke. You'd want to make sure it's well-seasoned, use it on stronger meats, and maybe mix it with a milder wood.
The Turtle is very correct about black walnut. It is strong. Tread lightly my friend.
Indeed...it is stronger than Mesquite - with a particularly sharp-bitter twang. Tho....IF you use it as an "accent" flavor, and at a low ration to the main wood ( cherry, preach, apricot, plum or other stone fruit ) it can be pretty good. Surprisingly good. But I would keep the amount at no more than 20% of the total amount of wood used.
I use Black Walnut often for beef. While it is a strong flavor, IMHO it is NOT stronger than mesquite, and nowhere near as bitter; not by a long shot. Mesquite is a very dirty, bitter, peppery wood, and it's very easy to over-smoke meat with it. Black walnut, is more like a very strong hickory (think hickory X 5) with maybe a slight bitterness.
BUT here's the caveat: If you are using chunks, I would recommend removing the bark because the bark can be very acrid.
I agree with Paul (Ka Honu) that it's best used with a meat that can stand up to it's flavor, which is why I use it mainly for beef. In fact it's my favorite wood to use for beef, especially steaks, without mixing it with any other wood.
Also, just like Hickory, Black Walnut mixes really well with apple for pork. Or to kick up Hickory's flavor a notch, add a bit of black walnut.
But DON'T be afraid to try it!
