Americans love to invite friends over for a barbecue — but when they do, they’re almost surely grilling, not barbecuing. True barbecuing is a demanding process of slow smoking requiring a special cooker or a great deal of attention to heat management.

That’s one of the clear lessons learned by the students in Copia’s first intensive Mastering the Grill course, taught by Andrew Schloss and David Joachim, authors of the book of the same name.

The course was conducted in two parts, with most attendees opting for the two-day session, and the most dedicated staying on to master barbecuing, too.

The all-day classes started with lectures in Copia’s theater, where the two grilling experts lectured about the basics and then the subtleties of cooking with fire. Then the students strolled over to Copia’s South Garden pavilion, where an array of gas and charcoal/wood grills were set up for them to try out literally dozens of cooking techniques and recipes.

The classes started with the basics of direct cooking of meats, the most common method used by backyard cooks, then moved on to indirect roasting of meats, cooking vegetables, then different techniques such as cooking on a plank as was traditional among Northwestern Indians, cooking dough on the grill, and then the actual smoking and barbecuing.

The class started with almost 24 people from as far away as Maryland and Louisiana, the latter a couple with their grown daughter. A number of couples also took the course.

Andy Schloss, who has been a chef, culinary instructor and author, says he and Joachim decided to write their impressive tome because other barbeque books focus on the history and romance of the craft, not the science behind the cooking. “What was missing was an analytical, scientific look at the culinary aspects of grilling,” he said.

As might be expected, the book and the course were heavy on technical information, perhaps too much for some of the attendees who were wondering about noon the first day when they were going to start cooking, much less eating lunch.

Schloss discoursed a bit on why grilling is so popular: “New flavors happen with fire. Most flavors come from the ingredients, and some from conventional techniques, but the flavors from fire are incredible. Fire does something special to food.”

Two types of special flavors come from grilling: caramelization from the meat or vegetable on the meat grate or radiant heat, and juices dripping on the coals and burning.

Of course, cooking with fire also provides a connection with our primitive hunter-gatherer ancestors, and men infamously love to recreate their ancient roles as they cook slabs of meat over a fire.

There are many types of grills; the key element is a grate, though a few styles of cooking over a fire use only skewers or rotisseries. The simplest way to cook is on a grate over a fire, of course, but adding a lid increases the versatility of the grill enormously. It allows you to control the airflow and hence the heat, and it creates a virtual oven, vital for cooking (really roasting) many items like thick pieces of meat or baking potatoes.

The top serves two purposes: It traps heat and allows it to reflect back onto the meat, and it also allows convection currents to develop, intensified the processes of cooking.

These days, most people use gas grills for their convenience, but Schloss and Joachim point out a critical difference between using gas and using charcoal or wood burned down to coals: The gas gives off a large amount of water, reducing the heat. You can get a far hotter fire with better searing using wood or charcoal. This is important in some applications.

The most popular charcoal grill — few people use hardwood in this frantic modern world — is the covered kettle developed by George Weber. It’s effective and versatile, with ports that allow careful heat management and concentrated heat.

Lump charcoal burns hotter than briquettes, but the briquettes burn longer; Schloss recommends using both together for optimum heat and longevity.

The authors are very high on indirect cooking — roasting — with the coals or heat split and none immediately under the meat. This indirect heat cooks evenly and avoids burning flare ups.

The authors offer a number of hints for home grillers:

• Get the fire (and grate) very hot to keep from sticking.

• Oil the grate — and the food.

• Take the meat out of the refrigerator to take the chill off.

• Dry food to make sure there’s no water on the surface as it will reduce the heat.

• High heat browns faster, but it doesn’t cook faster — it just leaves the center raw and the outside burned.

• Don’t touch the meat or vegetables until a crust has developed — it should then release on its own.

• Rubs are a great way to flavor meat and vegetables. They’re better than marinades in most cases.

• Tough meat is done when the connective tissue is above 150 degrees.

• Sear steaks on first side with the lid on, then turn and leave lid off.

• Brining makes a dramatic difference in dry pork and poultry, yet little salt remains in the meat.

• Thoroughly clean your grill occasionally.

Although focusing on outdoor grilling, Joachim admits that at times, we want barbecue flavors without bothering to grill outside, and grill pans and electric grills like the Forman grill have become popular for that reason. Joachim says they’ve found that the pans actually give better flavors than the electric versions. Fats burn in the grooves, giving off smoky flavors missing from the appliances..

And that elusive barbecuing? It’s a long, slow process by which the meat is infused with smoky flavors. The meat should cook at 200 to 225 degrees for a lengthy period — many hours in fact — so touch cuts like brisket or shoulder get tender. It’s easiest with a dedicated smoker with two chamber, one for the fire and another for the meat, but can be done in a kettle or other covered grill with careful management of heat.

If you’d like more information about grilling — virtually a complete master course, in fact — and a vast array of recipes, the book, “Mastering the Grill” is available at Copia and elsewhere for $24.95.