The cooking surface of your grill is one of its most important parts of your grill. The material should be strong and resilient. It should also provide good heat transfer, be durable, and keep food from sticking.
Your grate doesn't necessarily need to be a non-stick surface, as in Teflon, but food shouldn't stick any more than necessary.
The Most Common Grate Materials
Typically, gas grills have either cast iron, porcelain-coated cast iron, stainless steel, porcelain-coated steel, or just plain steel. The intense heat of the grill can wear down these metals if they are thin or poor quality. Over time, a grate that worked well when you bought it can begin to produce less than desirable food. That is why it's a good idea to spend a little extra time choosing the right grate.
In reality, the worst thing you can do to a cooking grate is to heat it up and then throw cold food on it, but that's grilling. We can't change the method, but we can choose the cooking surface. No matter the material, though, keeping the grate clean and in the best shape possible will help it last longer.
Steel grates tend to be the most affordable, which is appealing. However, steel and stainless steel do have some drawbacks.
With repeated use, plain steel tends to lose its temper and it will start to develop chips. This can make the surface rough and uneven, and, in turn, it leads to food sticking to the grate. The plain, thin rod-type of the grate is notorious for this, so it's best to stay away from this material.
Stainless steel can also lose much of its non-stick abilities and get chipped up, but not nearly as fast as the plain steel units. Stainless steel will work well for a long time if you keep it clean. It will not, however, stand up as long as cast iron or porcelain-coated surfaces.
Porcelain-coated steel or cast iron is a good choice, but the coating does have a nasty habit of chipping away. This can expose the metal underneath to moisture and may result in a rusty surface over time. This is especially true of coated cast iron, though coated steel can develop problems as well.
This isn't to say that porcelain coatings are all bad. It's often a simple matter of choosing a quality porcelain grate. While the price tag may be tempting, cheap porcelain coatings can lead to headaches down the road, and it may happen sooner than you think.
If you do have a porcelain-coated cooking grate, keep hard metal scrapers and tools away from it. A metal bristle brush is okay, but no scrapers. It's a simple step that can preserve the integrity of the surface for years.
Cast Iron Grates
Most dedicated grillers prefer bare cast iron and the heavier it is, the better. These offer a surface that not only gets hot but holds a lot of heat. It gives good grill marks and helps food cook faster. Cast iron may cost more, but it will last for decades if it's taken care of. Many people find that the investment is well worth it.
The drawback to a bare cast iron cooking grate is that it needs to be maintained. This means you need to keep it clean and make sure that the entire surface is well-oiled. It requires the same maintenance you put into any cast iron cookware, though you quickly get used to the routines involved.
During grilling, grease and fats will build upon the surface of the grate, which helps protect the grate. At the same time, the intense heat of a grill causes grease to vaporize and therefore burn away. With any cast iron part, it's important to keep this contradiction in mind.
Just because you grill fatty burgers all the time, doesn't mean that you have enough oil in the right places. Since you don't grill on every single square inch of the grate, you do need to take it out frequently for inspection. Make sure there is no rust and ensure that the grate is properly oiled.
The other benefit to cast iron is that you can use any metal tools you like. This means that you can invest in grill accessories that may last as long as the grate itself.
Your Best Options for Grates
Overall, a good, heavy cast iron grate is your best option for long-term durability and creating the best-grilled foods. The difference in the quality of your cooked meats is considerable and you'll soon learn why it's the preferred material for a barbecue.
If you don't want to deal with the work of maintaining cast iron, your next best option is a high-quality porcelain-coated cast iron grate. You get the heat characteristics of cast iron with a rust-resistant surface. When you buy your cooking grate, be sure to get a good grill cleaning brush that won't chip the porcelain as well.