Consumer advice organisation Which? has warned British households against cooking thin-cut bacon and grated cheese on barbecues ahead of a warm weekend.
Food experts at the organisation cautioned that dripping fat from thin bacon creates severe flare-ups that can burn food or trigger dangerous grease fires.
Natalie Hitchins, Head of Which? Home Products and Services, warned cooks about the dangers of poor preparation. "Getting it wrong could mean a messy grill," Hitchins said.
Which? is a long-established UK consumer advocacy organisation that tests consumer goods and publishes independent buying guidance. The group regularly issues seasonal advice on domestic appliances, outdoor equipment and food preparation to help shoppers avoid safety hazards and financial waste.
Thin-cut bacon and fat flare-ups
Thin-cut bacon tops the list of foods that can ruin a cookout, according to the consumer experts. While placing crispy bacon on top of a burger is a popular choice, experts say attempting to cook thin strips directly over open coals is a mistake.
Which? food experts caution that the fat content in thin bacon melts rapidly over the heat. Excess fat drips straight onto hot coals below, triggering uncontrollable flare-ups. These intense bursts of flame rapidly char the outside of food while increasing the risk of a dangerous grease fire.
Barbecue flare-ups occur when liquid fat or oil vaporises and ignites upon contact with glowing charcoal or heat diffusers. In outdoor cooking, sudden grease fires can spread to surrounding equipment, creating safety hazards and leaving stubborn carbon deposits on cooking surfaces.
Grated cheese and dairy risks
Grated cheese is another popular topping that experts say should never be placed directly onto the grill. While melted cheese is a classic accompaniment to barbecued burgers, using shredded or grated forms guarantees a ruined grill.
Which? explained that grated cheese "melts into the coals rather than onto your food" when exposed to direct heat. The process leaves burned cheese stuck to the iron grate and sends burning fat dripping downward to produce flare-ups.
Instead of grated cheddar, the experts recommend using sliced cheese or varieties with lower melting points, such as mozzarella or American cheese singles, which hold together better over heat.
Different cheeses react differently to heat based on their moisture content and protein structure. Semi-hard cheeses like cheddar separate into oil and solids when melted over high heat, whereas processed singles and fresh mozzarella melt more uniformly.
Puff pastry and heat distribution
Cooks looking to get creative by baking tarts or pastries over hot coals have also been advised to reconsider. Which? says that attempting to cook puff pastry over an open grill is unlikely to succeed in practice.
Puff pastry requires a stable oven environment and diffuse heat so that its layers can separate and form a light, crispy shell while cooking all the way through. The intense direct heat of a barbecue burns the outer crust long before the interior pastry is cooked.
For those set on cooking pastry outdoors, Which? suggests placing a cast iron pan over the coals to help diffuse the direct heat, combined with a lid or cover to create an oven-like cooking space.
Puff pastry relies on water evaporating into steam between thin layers of butter and dough to expand. Cast iron cookware retains and distributes heat evenly, helping to replicate the ambient thermal conditions of a conventional kitchen oven.
Leafy greens and vegetables
The urge to grill side dishes can also lead to mistakes with salad ingredients. Which? warns cooks to resist adding delicate leafy greens, such as spinach, rocket or kale, to the barbecue.
When exposed to the high heat of a grill, delicate greens will simply "wilt, burn and disappear" rather than taking on a pleasant smoky flavor, according to the group.
However, cooks seeking a smoky salad base can char heartier vegetables like romaine lettuce. Which? recommends cutting the lettuce in half lengthways, brushing it with oil, and placing it cut-side down over the flames for one to two minutes until lightly charred. This creates a base for a smoky Caesar salad.
Alongside warnings about what to avoid, Which? highlighted ten surprising foods that can be cooked successfully on a barbecue. The list includes watermelon, avocados, Camembert, pizza, oysters, halloumi, romaine lettuce, bananas, eggs, and fresh fruits such as pineapple, peaches and citrus fruits.
Halloumi, a traditional cheese from Cyprus, has a high melting point that allows it to be grilled directly on grates without losing shape. Similarly, fruits with high natural sugars, such as pineapple and peaches, caramelise when exposed to grill flames.
Fresh pasta, grains and raw rice
Fresh pasta is another item that culinary enthusiasts should keep away from the barbecue. Soft fresh pasta cooks in just one to two minutes, and larger types such as gnocchi may appear sturdy enough for grilling.
However, Which? cooking experts urge cooks not to attempt the experiment. The group noted that fresh pasta "sticks instantly and falls apart" the moment it touches hot coals, rather than becoming crisp or smoky.
Similarly, raw rice and uncooked grains cannot be prepared on a barbecue. Because these grains require water to soften and cook, roasting them over coals will not make them edible, no matter how long they stay over the heat.
Which? advises anyone wanting rice or grain side dishes to cook them indoors on a kitchen hob or in a rice cooker before serving them alongside barbecued meats.
Gnocchi are soft Italian dumplings typically made from potato, flour and egg, while rice and grains rely on starch gelatinisation through boiling water. Without liquid absorption, dry heat causes raw grains to scorch rather than soften.
