Finally, a Grigne!
I've been making thin couronnes lately, because I can give the loaf a real stretch like baguette, but still have it fit on my oven stone (heck, fit the oven itself). I haven't had much luck with getting a good grigne, tho... until today! I just had to share a picture. I hope I can do this again!
I reduced my initial oven temperature to 475F to avoid setting the crust too fast, added water for steam some time before the loaf to avoid a steam flash, and worked on my slashing with the safety-razor-blade-on-a-coffee-stirring-stick trick, but it wasn't quite right, and my slashes would never get that lip pulling up and browning to a crisp.
Today, I proofed the loaf under a tea towel, but with a metal bowl full of hot water set in the ring of dough. I'm not sure that's what really made the difference, altho I did notice that the skin near the bowl was drier, which may have helped the loaf to expand outwards and pull on the slash... maybe?