Don’t think that just because you’ve got some jalapenos, that you’re guaranteed some heat. You can actually buy a bunch of them at the same time, only to find some will have no more zip than a bell pepper.
Newer varieties have been developed that are not only milder, but also resistant to disease. They seem to have penetrated the market, according to broncosaurus. The peppers that are the brightest green are often of that new variety called TAMs (after the developer, Texas A&M). JMF has found that the hotter peppers have black or purple striations near the stem end. Leave the interior ribs and seeds in for more heat.
They’re a hot weather plant, so look for them at farmers’ markets in August and September. When you find some to your liking, buy up a lot and freeze, advises MakingSense.
They’re easy to grow, if you live in a climate with long, warm days. They’re ornamental, as well.