La Barbecue pitmaster John Lewis and his new brisket pit. (Photo ©Chris Wilkins/Texas BBQ Posse)

In Texas barbecue, competitive secrets are valuable. And a photograph, apparently, is worth much, much more than a few lousy words in a blog.

No pictures. No pictures, La Barbecue pitmaster John Lewis kept repeating as he gave us a tour of his new pit during our recent tour of the best joints in Austin.

Lewis claims he has built, with the help of his father, the world's first offset convection cooker that operates without any mechanical assists, such as fans or blowers. Offset refers to the firebox hanging off one end of the pit.

He didn't mind talking for publication about his invention. He just didn't want anyone to take a photo, especially of the two ends, which contain all the magic, as far as barbecue is concerned.

Why is this better? I asked him.

"You're going to taste it," he said. We did, but we'll save talk about his food for another post.

The key elements of convection barbecue cooking are uniform heat and smoke, which lead to uniform doneness and taste. Lewis said his briskets, which take many hours to cook, are all finishing within 45 minutes of each other on the new pit.

The exterior of John Lewis' new smoker at La Barbecue. (Photo ©Chris Wilkins/Texas BBQ Posse)

A toilet analogy may not seem appropriate in a food story, but it works here. Think of the swirl of water created when a toilet is flushed. The same thing happens in the firebox of Lewis' new pit.

The outside of the firebox has square corners, but the inside is rounded, helping create a swirl of heat and smoke that goes up into the cooking chamber, continuing to swirl, and then out the stack.

"It draws unlike anything I've seen before," Posse co-founder Chris Wilkins said.

Lewis said the pit took him 3 months to build in his off hours, which are few. He discovered its drawing power one night while smoking a cigarette and watching the fire from a few feet away. The smoke from his cigarette got pulled into the firebox, he said.

Followers of the Posse's Facebook page may be scratching their heads and asking, "But didn't I see a picture of that new pit?"

Yes, you did. A friend of the Posse took a photo and sent it to us. Wilkins quickly posted the shot. New pits are news. But later, after the friend discovered that the photo revealed a competitive secret, he asked Chris to take it down. He did.

So, if you saw the photo and didn't really know what you were seeing, no problem. If you recognized the secret, get that welding torch fired up.

La Barbecue "Cuisine Texicana", 1502 S. 1st St, Austin, TX, 512-605-9696. Open Wed-Sun 11 am-til the meat runs out.

John Lewis talks sausage with Posse member Bryan Gooding, aka the Sausage King of Oak Cliff. (Photo ©Chris Wilkins/Texas BBQ Posse)