Peppers pop during frying because their skin acts like a waterproof membrane: the air inside and the pepper’s own moisture turn to steam when heated, pressure builds, and the skin tears at its weakest point. This tear sends hot oil splashing outward. Thoroughly dry the peppers before adding them to the oil, and pierce each in 1 to 2 places with the tip of a knife to greatly reduce both popping and splattering.
There is a hollow space inside a pepper, and that space contains air. When the pepper goes into hot oil, this air expands, while the water in the pepper’s flesh also begins to turn into steam. Because the skin is thin but tight, pressure builds inside for a while. Eventually, the skin tears at one point, and as the hot steam inside suddenly escapes, it throws the surrounding oil outward too. That is why the sound is sudden and sharp; splattering oil can reach the area around the stove and the person frying the peppers. The same pressure builds during grilling over embers, which is why peppers crack over a fire.
The simplest precaution is to pierce the peppers. Before each pepper goes into the oil, pierce it in 1 to 2 places with the tip of a knife or a fork; for a long green pepper, the middle of the body is enough, while for a çarliston pepper, the thickest part is enough. The holes let steam escape before it builds up; pressure does not rise, and the pepper does not pop. Pierced peppers fry noticeably more quietly. Some kitchens slit peppers lengthwise. Do not remove the stems, because the opening at the stem end lets a lot of oil into the pepper and makes it greasy. Pierce all the peppers at once, before they go into the pan.
The second precaution is drying. Water on the surface of washed peppers causes the splattering as soon as they enter the oil. After washing the peppers, dry them one by one with a paper towel and wipe away water around the stem ends too. Arrange the peppers in a single layer with space between them in the pan; peppers piled on top of one another will not brown evenly and will trap each other’s steam. Use tongs to place them in the pan away from you; do not drop the peppers in from above. Once the stem ends are dry, check the peppers one more time.
Protecting yourself from splatter is also part of the process. A fine-mesh splatter screen placed over the pan lets steam escape while catching oil droplets. Do not use a solid lid; steam that collects on the lid can drip into the oil and increase splattering. Add enough oil to coat the bottom of the pan in a thin layer; the peppers do not need to float in oil. Medium heat is sufficient; in very hot oil, the pepper skin will brown immediately while the inside remains uncooked. Turn the peppers once, and remove them when their skins blister and develop a mottled color.
Peel fried peppers if desired. Their skins come off easily after the peppers rest in a covered container for a few minutes while still hot; this rest softens them a little. Drain the fried peppers on a wire rack and serve them with garlic yogurt or a vinegar sauce drizzled over the top. Tomatoes also pop for the same reason and can be pierced in the same way. When frying is finished, strain any pepper pieces left in the oil in the pan; these pieces will burn the next time the oil is used.