Heatlie BBQs have always used mild steel or stainless steel for our BBQ plates, burners and bodies. We've kept this tried and tested formula for decades because we've seen first hand that it stands a league above other options in terms of quality and longevity.
The most common other materials you would find in a non-Heatlie BBQ would be cast iron for plates and burners or vitreous enamelled steel for the body. We're going to focus on cast iron, and why mild steel trumps it as the best material for BBQ burners and cooking plates.
What are Mild Steel and Cast Iron Made of?
People often mistake cast iron as being pure iron. It isn't, and more surprisingly it isn't the iron content that makes it different from mild steel. Both are an alloy of iron and carbon, however, cast iron features higher values of carbon than mild steel. This gives it a distinct dark colour and rough texture. For this reason, it is also weaker and more brittle than mild steel and can break far easier.
Cooking with Mild Steel vs Cast Iron Plates
Mild steel is an excellent conductor of heat and thus will heat up nice and quickly. This means less standing around waiting for the BBQ to preheat. Its higher conductivity means that the heat will spread evenly across the whole plate, with fewer hot and cold spots than cast iron. Mild steel plates are really good at creating a non-stick surface, so you can cook just about anything without worrying about it being ruined.
Cast iron plates are very common in your standard, cheaper BBQs. It is generally cheaper to make and provides a satisfactory cooking experience. However, it doesn't conduct heat overly well, so it will take its time to heat up, and the chance of cold and hot spots is high as the heat doesn't spread evenly across the plate or grill.
One huge advantage of mild steel is that you can cut it at larger thicknesses for more versatile use. Heatlie offers plates in 5mm, 10mm and 20mm. The thicker the plate the better the heat will spread and the more reliable. It also means the plate won't warp under long heat exposure.
Cast iron is way less flexible and is "cast" meaning it gets poured into pre-made templates at molten state and then sets to it's hardened state. This results in most plates only being a few millimetres thick and not being resistant to warping and heat damage.
Caring for Cast Iron
Cast iron plates and burners are highly susceptible to rust. It needs to be kept seasoned at all times to protect it from oxidation. The lifespan of a typical cast iron burner is only brief. As they are often placed underneath a grill, they get hammered by just about everything that drops in between, meaning they are exposed to rust and rarely cleaned. Their flame holes can easily get clogged up with fat which means less heat.
Mild steel also needs to be kept seasoned to avoid rust, however with thicker more durable plates rust can be scraped away and re-seasoned. Cast iron plates often rust through much quicker.
Caring for Mild Steel
Caring for mild steel is a very similar process to cast iron. All it needs is to be cleansed of food scraps with a scraper and re-oiled to keep the steel protected from oxidation. The mild steel plate on your Heatlie will develop a thick, shiny black coating over the process of many cooks. This simply means it is performing at its non-stick best and is at its peak for cooking.
Mild Steel Burners on a Heatlie
Mild steel burners are also susceptible to rust, however on a Heatlie, they are hidden underneath a solid plate and don't get exposed to all the atrocities that cast iron burners will. The typical lifespan for a set of mild steel burners is 8-10 years.
Enamelled Cast Iron
You will find that some cast iron burners and plates come with an enamel coating that is baked on at high temperatures. This means that the cast iron has an extra layer of protection from corrosion. It makes it generally easier to care for, but it isn't bulletproof and can be chipped if struck hard enough, or can crack at high temperatures.
So what's the verdict?
If you're after a long-lasting, durable BBQ that gives you a killer cook every time, you can't go past a Heatlie mild steel plate.