When it comes to grill construction, a lot of attention is paid to the exterior; what kind of metal it is, how thick, how large, are the legs sturdy, etc. So much so that the importance of the interior construction is often overlooked by prospective grill buyers, who may assume that all grill grates are pretty much the same.
This couldn’t be further from the truth. The grill grates are possibly the most important part of your grill in many ways, as it will be the bit that suffers the most wear and tear, put under stress each and every time you use your grill. Perhaps the only exception is the bottom of the grill, where the coals go, but that bit is made of significantly thicker and more durable metal on average.
This means that for the most part, grill grates are the only part of your grill you’ll likely need to outright replace over the life of your grill, and at that point it’s important to know what your options are. While you have little control over the composition of the metals that makes up the grates that come with your grill, you often have a lot more choice when replacing broken ones (or those that simply don’t perform to your satisfaction).
There are essentially four options to choose from here, separated into two basic categories: covered metals, and bare metals.
Bare steel (usually stainless steel) grates are going to be the most common type you can find, and are the default that come with most low to mid grade grills. Stainless steel is a great material for a lot of things, though is honestly only so-so at best for grill grates. Not only are they less durable than other options (especially since they’re often constructed poorly, with just thin rods), they have fairly poor heat conductivity, taking longer to heat up than other options.
Cast iron is all around better in most regards. Not only are cast iron grates thicker by necessity, they have superior heat conductivity to steel, and are all around more durable in most ways. As an added bonus, cast iron (when properly seasoned) is naturally nonstick, making it easier to cook on than steel.
It should be said though there’s a fairly large drawback to using cast iron: it rusts. You need to take very good care of cast iron products of any type, and grills generally being stored outdoors or in a non-climate controlled storage space means that moisture can easily get into the grill, causing the grates to rust.
Stainless steel is therefore a whole lot easier to take care of, even if as a material it’s not as good as cast iron for most purposes.
However, there is something that tips the scales back in cast iron’s favor: coating. Specifically, a nonstick porcelain coating. The benefits given to stainless steel are fairly minimal; it grants nonstick properties to a surface that is not natural nonstick.
But for cast iron, it’s a whole other ball game. The porcelain coating protects the cast iron interior from water damage, increasing the longevity of the cast iron grates and drastically cutting down on the effort required to keep them clean and well maintained so they don’t rust.
There is a bit of a drawback to this as well though, which is that the porcelain coating is fairly thin, meaning they’re prone to chipping over time. This will gradually make them harder to clean, and reduce the benefits provided; steel will start sticking more, and cast iron will begin to rust. The coating is a supplement to, but not a replacement for proper maintenance.
The only other thing worth mentioning is a fairly rare option: anodized aluminum. Anodized aluminum shares many of the upsides of stainless steel. It doesn’t rust, and is easy to clean with a brush and an all purpose cleaner. It also has superior heat conductivity, heating up and cooling down with extraordinary speed, allowing it to sear well.
Unfortunately, as mentioned, this option is hard to find. It’s also a bit less durable than either steel or cast iron, and can be harder to clean off stuck on food; grills are best cleaned while the grates are still warm, and as mentioned aluminum cools off very quickly.
Of these options, I think the best by a fair margin is porcelain coated cast iron. As a material it has many qualities that exceed those of other, similar options and very few true drawbacks, being easy to maintain and use, with excellent performance.
However, keep in mind that material is not the only factor you’ll need to consider. Of equal importance is the construction of your grill grates.
Most cheap grill grates are thin rods. They use as little material as possible to keep costs low.
These rods are easy to bend due to the stresses they’ll be put under when heated, and break down quickly.
What is significantly better is to look at grates which are either made from thick bars (most cast iron grates are made this way) or are crafted into “flavorizers”, or triangular shapes. These are not only more durable than rods (though perhaps less so than bars), but also promote more even cooking and the delicious kiss of smoke that are made when grease drips onto the angled sides.
There’s not much point in fretting over the material of your grill grates if their construction does not do that material justice, so make sure to keep both things in mind when buying your grill grates.
Just don’t stress TOO much about it either way. Any grill grates will get the job done, so it’s not worth paying some insane premium for better grates. It’s generally better to let the original grates wear down first, and wait for a sale so you can snag replacements at a great price.