After a few weeks of relatively intense house projects due to a rapidly approaching deadline, the backyard grill provided a distraction. As in, the grill itself was the distraction--it was time to install some lava rocks.
Flavorless flavorizing
I've cooked on gas grills with lava rocks, albeit many years ago. Lately, though, all of the grills in my price range have what many manufacturers call heat tents, flame tamers, or--the worst, at least in terms of misnomers--flavorizer bars. Whatever one calls them, these are the angled pieces of sheet metal which sit directly over the burners in a gas grill. Their primary job is to prevent flare ups by instantaneously burning off grease from the cooked food, provide (relatively) even heat at the cooking surface, and to protect the burners from grease drippings.
Flavorizer bars do all of these tasks quite well. They rust out eventually, but replacing them is about as hard as replacing a roll of toilet paper. The real problem I've always had with flavorizer bars is the flavor--they don't provide much, if any, flavor. The grease from the food burns off so quickly and efficiently that it barely smokes when it burns. This efficiency, and the lack of smoke that is produces, provides a grilling experience that is more akin to cooking in an oven--clean and efficient, rather than the smokey mess that makes grilled food special.
A secondary downside to the grease-burning efficiency of flavorizer bars is that they don't provide much additional heat to the grilling surface. The grease hits the flavorizer bar, vaporizes instantly, and is gone--which leaves the burners to do all of the heating. This would seem like a good thing, as long as the burner itself is capable of providing enough heat to sear a steak. In many sub-$300 grills, though, the burners don't always provide sufficient levels of heat, which--when coupled with the gaping holes that many manufacturers leave open on the back of the grill for "combustion" purposes--makes for unpredictable-to-difficult grilling.
Why lava rocks?
Lava rocks, on the other hand, do provide both flavor and a secondary heat source. The holes in lava rock capture grease, and ignite it--but the ignition is not as incendiary as it is with flavorizer bars. With lava rock, grease burns more slowly and less efficiently, which causes more smoke. The char and creosote in the smoke adds flavor, and the continuous ignition of grease in lava rock creates a secondary heat source in and of itself.
This is not without downside, though--the buildup of grease can lead to flare-ups with lava rock, which can quickly turn red hot dogs into black pencils. This requires a cook to take a more active role in the cooking process, rather than simply throwing things on the grill and walking away for ten minutes. And when you add in the use habits that most people have with with their gas grills--that being, a ten minute warm up time (which is generous in some cases) and then turning the grill completely off as soon as the food is removed--grease builds up without burning it off in a productive manner. This leads to uncontrolled flair ups (the grease from all of last month's cooking is now charring tonight's four burgers!), which leads many people to draw the conclusion that "lava rocks are bad."
Which isn't true. Lava rocks aren't bad; they flair up uncontrollably when they aren't used properly. When you allow the grill to come up to cooking temperature, and then allow the burners to continue running for a few minutes after each cooking session, you can keep the flare-ups from getting out of control. And when you control the flare-ups, you can get that grilled flavor and heat that flavorizer bars just can't match.
With lava rocks, you get flare ups. You cook over them. You get better flavor and better heat--if you don't want these things, then why are you grilling? Gas grills are the quick and easy alternative to charcoal grills, which basically involve cooking over a flare-up the entire time food is on the grill--and I have yet to hear anyone say that they can't stand the flavor of something that is properly cooked on a charcoal grill.
That being said, there is an alternative to lava rocks: ceramic briquettes, which are basically lava rocks but with smaller holes. You get smoke, but not as much. And you get flare-ups, but not as many. So ceramic briquettes are like diet lava rocks. Since I had never cooked over these, I thought I'd give them a try as well. The verdict will probably be out for a while, but the shape of the ceramic briquettes does make for a neat pattern inside the grill.
If you're so smart, then why are lava rock grills so rare?
Well, one reason was described above albeit, in a backwards way: most people don't want to grill. They just want to throw food on a grill, walk away, and have cooked food when they come back three beers later. Lava rocks, with their flare-ups, aren't conducive to that type of cooking. Flavorizer bars, due to their clean and controlled nature, allow for good results with less supervision. As most people don't want to supervise the cooking process any more than necessary, replacing lava rocks with flavorizer bars was a logical response on the part of the manufacturers.
Another reason that I suspect flavorizer bars are used in many grills is due to cost. Flavorizer bars are incredibly simple items: they are nothing more than bent sheet metal, and they are often held in place by nothing more than gravity. They are light, cheap to make, and--unlike a bag of rocks--are easy to pack and ship.
When you add the cheap and easy-to-pack nature of flavorizer bars to the aforementioned laissez faire cooking methods used by many grill owners, flavorizer bars make sense. But, when it comes to flavor and heat, it is my opinion that flavorizer bars are not as good as the old fashioned lava rocks.
So, what can be done?
Back to my cheap grill. I like my grill. It has stainless cooking grates, a side burner that I like to use to light a charcoal chimney, and has enough cooking area to grill burgers, zucchini, and corn at the same time. Unfortunately, its burners provide uninspiring heat, the combustion vent gap between the lid and the back of the cooking box is big enough to put your arm through, and it uses flavorizer bars rather than lava rocks.
Fortunately, I also own a cheap welder, know a place where I can get metal for cheap, and lava rocks are cheap. And thinking is free--so why not figure out how to add heat and flavor to the grill by replacing the flavorizer bars with lava rocks? All told, once I had gathered all of the parts, it took less than an hour to make the change.
This is what the flavorizer bars looked like when I started.
But then I started. First, I gathered the parts--a piece of expanded sheet cut to the same dimensions as the inside of the grill and eight 1/4" rods cut to the same length as the flavorizer bars. Two rods would sit in each flavorizer bar perch and support the expanded sheet.
Second, I arranged the rods.
Then I set the expanded sheet on top of the rods and started welding. A couple of welds per rod would have been sufficient, but I need to work on my welding skills--and since these welds will always be hidden under lava rocks or ceramic briquettes, it seemed like a good place to practice.
Once I had welded to my satisfaction, I put lava rocks over half the grill...
...and ceramic briquettes over the other half. I put my smoker chip box in the middle, but I imagine I will end up moving it to one of the ends so that I can have a two-zone cooking area when I feel like smoking something on the gas grill.
Once everything was in place, I threw some cheap brat-burgers on the grill. The smoke was present right away on the lava rock side of the grill. The ceramic briquettes also smoked, but not as much. But on both sides, the improvement vs. the old flavorizer bars was obvious--the smell was incredible, the smoke drew my neighbor over from his back yard, and the flavor of the burgers when they came off the grill was unlike anything that had been cooked on the grill before the changes were made.
