Interresting article about jalapenos & heat here:
"Ever take home a jalapeño chile pepper from the grocery store and have it either be so lacking in heat it may just as well be a bell pepper, or so hot a speck will create a raging inferno in your mouth? Here's a quick tip for choosing jalapeños that can help you decide which ones to pick. Jalapeño chilies progressively get hotter the older they get, eventually turning bright red. As they age, they develop white lines and flecks, like stretch marks running in the direction of the length of the pepper. The smoother the pepper, the younger, and milder it is. The more white lines, the older and hotter. Red jalapeños can be pretty hot, if they have a lot of striations, but they are also sweeter."
Source:http://simplyrecipes.com/recipes/tip_how_to_check_for_the_hotness_of_jalapenos/
