Left on the plant (and even after picked) green jalapeƱos will eventually turn red. So red jalapeƱos are older than green jalapeƱos. The red ones can be pretty hot, especially if they have a lot of striations, but they are also sweeter than the green.
Subsequently, question is, what does it mean when a jalapeno turns red? Like sweet pepper varieties, jalapenos turn red as they ripen. The ripening process does change the flavor, although its effect on a peppers hotness depends on a variety of other variables including weather conditions and the genetics of the particular plant.
Considering this, can you use red jalapenos?
A green jalapeƱo has a fresh, crisp taste whereas a red jalapeƱo has a bit more sweetness to it. This can make a difference in recipes. Some prefer red jalapeƱos in hot sauces. In fact, Sriracha Hot Sauce, one of the most famous hot sauces in the world, uses red jalapeƱos as its base.
Is a Fresno pepper a red jalapeno?
Fresno peppers change from green and turn red as they grow, and increase in hotness, but they are often harvested and sold as green. The green peppers are mild to medium hot, while the mature red Fresno is quite a bit hotter, surpassing the jalapeno.