Theories abound as for how to determine just how hot a jalapeño is: Some claim that smaller jalapeños are spicier than their larger ilk. Others say that a pepper with a pointy tip brings the heat. While the smaller peppers theory more or less holds true when comparing varieties of peppers — think of the heat and size correlation between bell, jalapeño, serrano, and Thai bird chiles — from jalapeño to jalapeño, not so much. As for pointy-tipped peppers: this seems more old wives' tale than truth. Visual cues related to the age of a jalapeño, such as white striations on the pepper (they look almost like stretch marks) or a red hue (jalapeños change from green to red as they mature), can signal a hotter pepper, but we've also had our fair share of shiny, smooth green jalapeños that set our mouths on fire. In our experience there's only one surefire way to tell: taste it.