Grilling burgers for your child’s birthday party or summer family get together is an ideal way to make your guests happy, especially if you have a fixins table with everyone’s favorite condiments. The key to serving a large group is to buy the right amount of food, especially ground beef, do as much prep work in advance as possible and have several people signed up as cooks so that you are not tied to the grill all evening long. Another important factor is to keep the burgers hot and juicy once they are cooked. This is easily accomplished with a covered aluminum tray.

Successfully cooking for a large group requires some math. How many people do you expect to feed? How many hamburgers will each person eat? If you are cooking for a larger group or a group of people you don't know as well, go for an average of 1.5 hamburgers per person. Some people will eat just one, some will come back for a second. Assume one-fourth to one-third of a pound of ground beef per hamburger. If you have a group of 25 people, they will probably eat 37.5 hamburgers. Round this up to 38 or an even 40 hamburgers. Depending on how large you make your hamburgers, you will need between 9.5 and 13.25 pounds of ground beef.

Make your hamburger patties the day before the party. You may want to mix ingredients such as herbs, garlic or onion powder, or spices into your hamburgers. This will give the flavors time to mix with the fat in the meat. Place 16 to 30 hamburger patties on a tray, depending on how many you can cook on your grill at one time. Wrap the tray with plastic wrap and store them in the refrigerator until you are ready to cook.

When your grill is ready, remove one tray of hamburger patties from the refrigerator. Leave the remaining trays in the refrigerator until you are ready to cook the next batch. This will prevent the meat from coming to room temperature, where harmful bacteria can grow. Cook the hamburgers until they reach 160 degrees Fahrenheit in the center. Remove the hamburgers from the grill and store them in a covered aluminum tray to stay warm until the rest of the hamburgers are finished.

Lay out hamburger buns, vegetables, toppings, condiments and side dishes on a large buffet table. Be sure to refrigerate any leftover hamburgers, mayonnaise or other perishables within two hours to prevent spoilage.