Smoking Food or Grilling?
This question is in danger of leading us into international waters. The Southern US states – seen by many as the 'home of barbecue' – would see smoking as the normal method; for them, anything else just isn't barbecue. What we in the UK generally refer to as barbecuing, they would call grilling. There's a difference between the two techniques and they produce very different result. What we're looking at here though, is the equipment.
What's the Difference?
In a conventional barbecue, food is cooked over a dry, high heat; the food is often directly over the coals and open to the air; i.e. no lid. It cooks quickly and is therefore better suited to smaller items such as the traditional burgers, chops, sausages and kebabs. The process tends to remove moisture content from the food; which is why marinating and basting meat is so popular when barbecuing because it add moisture as well as flavour. With a smoker, on the other hand, the lid is down, putting the food in a closed environment. The heat is not direct and its purpose is to create hot smoke which then passes through the cooking chamber. Smoking takes more time and gives a much more moist, tender result. Due to the longer cooking time (and lower temperatures) it is suited to cooking larger cuts of meat like roasts, hams and ribs.
At the risk of confusing the issue, as long as your conventional barbecue has a lid, you can contrive to smoke with it; and if you leave the lid on your smoker open and put the charcoal directly under the food, then you can grill with it. Functionally, the two items can be interchangeable, but that doesn't change the fact that they are each designed for very different cooking processes.
One of the key differences is operating temperature. The conventional charcoal barbecue is cooking your food at 400 degrees Fahrenheit or thereabouts. This means that as the chef, you are turning the food much more frequently in order to prevent burning, which in turn means that you are paying a much more constant attention to the whole process. We've all been there, get distracted, turn your back for five seconds and the burger that was still half-raw the last time you checked has turned into some sort of meteorite. The upside of having to watch the grill like a hawk is that the food does cook quicker on this higher heat. The downside is that it dries the food; not such a problem for burgers and sausages which a fairly moisture-rich to start with but barbecued chicken can be very dry and tough if you're not careful.
When it comes to flavour, food cooked in a smoker tends to taste smoky (well, obviously) so the conventional barbecue tends to be your best bet is you like spicy food. Putting chilli in your burgers and then cooking them in a smoker just masks the heat of the spice. To really bring it out, you need the 'cleaner' heat of a grill – not everything tastes good smoked. That said, sweet sauces and marinades can be enhanced by cooking in a smoker; horses for courses.
One way of approximating the smoker effect with a conventional barbecue is to move the hot coals so that they are not directly under the food and close the lid, creating a sort of oven effect. If you add some damp wood chips to the heat as well then that will give you a smoked flavour. Different chips – hickory, mesquite, applewood, etc. – can be bought to give different flavours; experiment to find what goes best with which foods.
The fire in a smoker usually is often in a separate chamber connected to the side of the main cooker. You build a charcoal fire in the side box and add damp wood to create the smoke. Alternatively, you could go for an all wood fire, but you don't want a high heat, you want it to smoulder gently.
Because all the heat is being transmitted via the smoke, the temperature is much lower in a smoker – around 250 degrees Fahrenheit – which means that you don't have to fiddle with the food so often. As chef, your monitoring duties are more about the temperature itself and many smokers will have a gauge on the lid of the cooking chamber. The fire tends to be small but you need to keep it fed to maintain the right level of heat. The lower temperature and slower cooking time means that the meat retains its moisture and is slowly penetrated by the smoke, giving that distinctive Southern American barbecue taste.
One thing a smoke can do that a conventional barbecue can't, is smoking for preservation. Properly-bringed meat that is then smoked can still be perfectly edible 10 months later. Try that with a grilled sausage.
One other factor: smokers tend to be bigger than conventional charcoal or gas barbecues (not always but often); available storage may be factor in your decision.
In the end, neither is better than the other – smoke or conventional – because they are designed to do very different things. Ultimately, your choice will probably be driven by your taste buds. What do you prefer to eat: smoke or grilled?