After a few years of cooking on both lava rock and flame tamer barbecues, this guide is based on my experience with cooking with both types of gas barbecues.
Important update: After getting several stories of gas barbecues quickly disintegrating or bursting into flames and brand bashing, I’ve decided to disable and remove the comments on this article. Please see the section below on fires and corrosion and carefully read the manual that comes with the barbecue, otherwise your first cooking session on a new gas barbecue could be its last!
Cooking with Lava Rock
Up until a few years ago, pretty much all entry level gas barbecues came with lava rock, including my first gas barbecue, the Outback Omega 200. The lava rock looks just like charcoal briquettes and their purpose is to give a similar cooking experience to cooking on charcoal. Higher end barbecues came with ceramic briquettes, which functioned much the same but had the advantage of even heat distribution.
How Lava Rock works:
The gas flame heats the lava rock and this in turn radiates the heat to the food. The food juices drip on to the lava rock, which turns to vapour and smoke. This raising vapour and smoke bastes the food to give the all-familiar smokey barbecue flavour. This is different to infrared/sear grills which let the drippings fall into a collection tray, where very little flavour is added to the food.
Advantages with lava rock:
One thing I do like about lava rock is that the majority of juice/grease drippings from food are vaporised or turned into smoke. The only time any drippings make it to the grease collection cup is when cooking very greasy food such as 8 burgers simultaneously. As a result, lava rock tends to give a stronger flavour than with a flame tamer, very close to that of charcoal cooking.
Drawbacks with lava rock:
As the lava rocks are of different sizes, with gaps between the rocks, this results in hotspots, which means that food needs to be moved around regularly to prevent burning. As grease drippings can run down the lava rock and catch fire from the flame below, lava rock regularly flares-up, especially when cooking greasy food such as chicken legs/breasts. Excess grease can also drip on to the burner below, resulting in port-hole blockages over time, as well as corrosion from excessive juice drippings. With regular use, expect to replace the burners every 5 years. Another problem with lava rock is that it tends to get mouldy, especially when the barbecue is stored over the winter, making it an unpleasant clean-up task when taking the barbecue out of storage.
Cooking with a Flame tamer
A flame tamer looks like a hat or a sheet of steel bent into a ^ shape, with one flame tamer placed on top of each burner. The vast majority of barbecues sold today are equipped with flame tamers ranging from entry to top-end models, sometimes under different terms such as flavourisers, flavour bars, heat diffusers, etc. Some barbecues such as the Outback Trooper/Hunter have a single large flame tamer that covers all burners, which gives additional surface area for drippings to fall onto.
How a Flame Tamer works:
Same principle as Lava Rock: The gas flame heats up the flame tamer and this in turn radiates heat to the food. The food juices drip on to the flame tamer, which turns to vapour and smoke. This raising vapour and smoke bastes the food to give the all-familiar barbecue flavour. Don’t confuse the flame tamer based barbecues to infrared grills, which don’t have anything between the burner and the food.
Advantages over lava rock:
The main advantage I find with a flame tamer is heat distribution. Everything cooks evenly much like with an infrared grill, which means that food only needs to be turned midway and everything is cooked at once, unlike with lava rock where certain items need to be left on longer to finish cooking. There are no hotspots either, which means no annoying spot burning. Unlike lava rock, the flame tamer completely covers the burner below, preventing grease and juice drippings falling on to the burner. This prevents the burner clogging and also gives it a much longer live. A flame tamer is also a lot easier to clean than lava rock and thus is less prone to getting mouldy when the barbecue is left in storage over a few weeks.
Drawbacks with a flame tamer:
While flame tamers generally don’t have issues with flare-ups, excess grease drippings will cause an issue and when the flame tamer does flare-up, it becomes one large fat fire, so all food needs to be removed until the fire goes out. For example, when cooking 8 beef burgers at once, these generally need to be removed twice during cooking, as beef burgers generally always cause at least one large flare-up. Those who intend to cook burgers regularly on their barbecue may be better off with a lava rock barbecue.
Charcoal vs gas fires and corrsion
Gas barbecues behave very different to charcoal barbecues when it comes to flare-ups and corrosion. Although there are plenty of articles and discussions of gas vs charcoal cooking, it seems like most articles ignore the comparison of flare-ups and corrosion, which I’ll try to quickly run over.
Flare-ups, fat fires and gas fires
Charcoal barbecues use ventilation to control the charcoal burn rate and in turn the cooking temperature. If a fat fire occurs, its burn rate will also be limited by the ventilation. With charcoal kettle barbecues that have a hood, usually it is sufficient to close the vents and put the hood on to extinguish the flames. Do not try this with a gas barbecue!
With a gas barbecue, the control knobs control the cooking temperature. Gas requires plenty of ventilation to burn properly and thus do not have adjustable vents. If a flare-up occurs, it can quickly lead to a thermal runaway, causing a serious or out of control fat fire, especially with the hood down. Processed and fatty foods such as burgers, sausages and chicken wings are worst for flare-ups. If the fat fire spreads to the inner body or drip tray, it can burn away the protective coating and paintwork, ruining the barbecue.
Gas fires are another issue to watch out for. Always perform a leak test (see the manual) whenever taking out the barbecue or after changing the gas bottle. I know someone that had a gas cooker explosion due to their propane regulator getting frost damage. It delivered so much pressure that it blew the seals in their cooker. This can just as easily happen with a gas barbecue.
If you have never cooked on a gas barbecue, please read the instruction manual carefully, especially the sections that cover flare-ups, maintenance and leak detection. Start off with a small amount of food and never leave the barbecue unattended!
Processed food such as burgers and sausages often have high salt content. Salt is incredibly corrosive and anyone leaving near the coast is aware of how quickly the spray from sea attacks metal such as satellite dishes and car components. The same occurs in a barbecue when barbecuing food with a high salt content. The saltier the food, the more corrosive the drippings will be. Unlike charcoal barbecues, there is no ash coating to resist the salt impact.
Salt is also a hygroscopic and will attract moisture, even with the barbecue covered. If this salty greasy residue is left over an extended period, this wet salty coating will gradually corrode the metal and lead to the bodywork disintegrating over a few years. Before putting the gas barbecue away for the season, clean away as much residue as possible from the inside surfaces of the barbecue.
My advice would be to consider using a disposable or separate charcoal barbecue for processed meat such as burgers and sausages. Use the gas barbecue for whole meats such as poultry, steak, chops and so on and cut away any excess fat before cooking. Another option would be to try getting low salt alternatives for processed meat. If you prefer a saltier taste, just sprinkle salt on the food after cooking and away from the barbecue!