We explore the slow-cooking technique with Mill Scale Metalworks.

When we finally felt ready to buy a smoker, we knew there was only one place to call. Mill Scale Metalworks is located in Lockhart, Texas—halfway between Austin and San Antonio—where brothers Matt and Caleb Johnson make the finest custom smokers, we would argue, in all of the United States.

The Johnsons grew up outside of Waco, and from an early age, were learning about welding, woodworking, and fixing up cars from their father. Moving to the state capital in 2007, they started careers in architectural steel design, and as the barbecue scene started to take off, they found themselves building smokers for the famed Franklin’s Barbecue before striking off on their own in 2018, winding up in Lockhart, known as the barbecue capital of Texas.

“We grew up seeing a big smoker in everybody’s backyard—it’s part of the DNA here in Texas, you’re always smelling post oak in the air, it’s like the free outdoor air freshener,” says Matt, pictured above on right. “But what I thought was brisket as a kid is a totally different business than what we’re in now.”

Barbecue has a long history in their neck of the woods. It began with direct-heat cooking, with meat roasted over a frame of wood above the high temperatures of an open flame, according to Texas Monthly. Later, the practice moved to dug-out, in-ground pits, constructed and tended to by Black cooks, and by the late 19th century, they were built up, above ground.

As markets and eventually restaurants started selling barbecue, they moved inside an oven, which was moved inside of a building—at the same time that the American kitchen was transforming from one of open hearths to those of enclosed cast-iron stoves, in the name of progress and sanitation. 

But it wouldn’t be until the 1920s that indirect-heat cooking—the low, slow process that makes even the toughest cuts of meat fall off the bone—would become the holy grail of American barbecue that is has become today. There’s a good chance it began at the Kreuz Market in Mill Scale’s own Lockhart, and by the 1950s, the backyard barbecue craze brought with it the first commercially available “smokers,” sold as half-drum-like gadgets for Saturday picnics. Though it would still take another two decades for the now ubiquitous offset-style smokers to arrive, first in the form of custom smokers built from old oil pipes in the 1970s, and more recently, using decommissioned propane tanks, like the flagship smokers built by Mill Scale—now essentially a symbol of the Lone Star State.

In modern day, these manual steel smokers are a Luddite’s dream. There are no gadgets, gizmos, buttons, and definitely no digital computer screens. Instead, they generally consist of a simple cylindrical cooking chamber to hold the meat, a separate firebox for that burning wood on one end, and a chimney-like smokestack on the other, altogether drawing air, heat, and clean smoke in an open loop slowly and consistently around the meat.

At Mill Scale, these bad boys range in size from 94 to 1000 gallons, with the latter running 20 feet long, weighing 5,000 pounds, and hauled by their own trailers. Their design tips a hat to their upbringing around classic vehicles, from their natural patinas to white-walled tires, with functional features honed through conversations with chefs and pitmasters.

And with the fire-cooking craze booming, they also make Japanese-style yakitori grills, asado-style fire pits, outdoor kitchens fit with planchas, cast-iron grates, and more, with this global approach inspired in part by their own upbringing, with their mother hailing from Portugal. Their 10-person team cranks out both residential and commercial cookers for customers across the country and now around the world. 

The Johnson brothers are part of the ongoing evolution of Texas barbecue, and their goal is to make the technique approachable, far and wide.

“What we really want to make it a tool that brings people together,” says Matt, who shares his go-to tips below, including how to incorporate your cast-iron cookware. Spoiler alert: it’s a must-have smoker accessory.

Use indirect heat for big pieces of meat.

“An offset smoker is essentially an oven with convection and the heating element is smoke. That indirect heat allows you to take big cuts of meat that would traditionally be difficult to cook, tough in texture, with a lot of fat, and slowly break it all down into tender bites while still getting that ‘bark’ formation like a beautiful crust. It also allows the smoke density to infiltrate the meat and add a ton of flavor. Imagine cooking brisket on the direct heat of a grill; you would eventually burn the outside, but it would be raw and fatty in the middle.”

Start small.

“Start with kindling, wood chunks, small splits of wood, like nine inches in length and about an inch and a half in diameter. We personally like to stack the into little log cabins tyle with a little bit of charcoal in the middle to start the coal bed. To ignite it, you can use a propane torch or a tumbleweed fire starter or the butcher’s paper that your meat came in.”

Build a “clean” fire.

“You want what’s evacuating out of the exhaust stack to be thin blue or transparent smoke—not a gray, cloudy, train-style smoke. That has a lot to do with your woods selection and it has a lot to do with airflow. The first question we ask is: what is the wood—is it wet, is it green, is it hardwood, how big is it? Tuffy Stone said it best; use what’s local. In Texas, we use post oak, California has red oak, the Northeast has hickory, Mexico has mesquite. The key is using a hardwood that’s seasoned and dry. Otherwise, it’s going to be pushing out a lot of moisture and producing dirty smoke, which translates into a rancid flavor profile. The size of the wood is important; you have more control and even temperature if you’re using small pieces, but it also means you have to manage the fire more, replacing the wood more often. If you’re putting in big logs, it’s going to take a longer time to ignite and burn down, and then there will be temperature swings. When cooking meats like brisket, consistent heat is critical. And then the second is about airflow, which you need to have a clean burning fire. Fire needs oxygen to breathe. This comes in through the firebox, and you can crack the door to add more. But too much airflow can be a bad thing, too.”



On that note, mind the weather.

“Rain, humidity, wind, temperature. It can all have an impact. If wind is blowing into your firebox, you’re going to have accelerated airflow, accelerated draw, faster burning wood, it's going to increase your temperature. If there’s no wind at all, you might have to crack your door or open your vent a little bit more to add some oxygen and fuel your fire. If it’s cold out in the northeast, your wood is going to take longer to ignite, and if it has some ice on it, it’s going to take more time to start burning clean smoke. Here in Texas, that wood can be 90 degrees when it goes from your pile to your firebox, and it ignites instantly. That’s why a lot of times you see people staging logs on a firebox—they’re pre-warming those logs to ignite quicker.”

Take your time.

“Embrace the process. Using time and understand the power that is has, to your advantage or disadvantage, is the most important aspect of cooking with fire. If you’re cooking big cuts of meat that take 12 or 14 hours, give it the time it takes—it’s ready when it’s ready. You can always increase your heat and speed things up, but you just need to be aware that there’s a lot of nuance, and you could end up burning it. It is a slow process.”

But don’t save it just for Saturdays.

“It doesn’t have to be a special occasion or the Super Bowl to bust it out. I’ve been known to cook with fire on a Tuesday night. Choose thinner cuts of meat or vegetables for quicker cook times. You can make chicken wings in a smoker in about an hour, or I’ll do meal prep, where I’ll cook several whole chickens or a couple pork butts and then integrate those into dishes throughout the week. It doesn’t always have to take an entire day.” 

Smoke your cast iron, too.

“We use them for everything, from making cowboy cornbread to holding the fat trimmings of a brisket to rendering down tallow. I’ve even seen people do beef cheeks and carnitas in cast irons in the smoker. There’s a ton of stuff that you can do with it.”

June 29, 2023 — Dennis Powell