Appearance jalapeno pepper Size and Appearance: Jalapenos are typically small to medium-sized peppers, measuring approximately 2 to 3.5 inches (5 to 9 centimeters) in length. Heat Level: Jalapenos are considered a medium-heat chili pepper, ranging from 2,500 to 8,000 Scoville Heat Units (SHU) on the Scoville scale. flavor: Jalapeos have a distinctive flavor characterized by a combination of mild to moderate heat and a slight sweetness.