A Mexican joint I went to happened to have some on hand, so I asked for some diced fresh serrano for my salsa. What arrived sure looked like fresh serrano: small, skinny, and dark green. They had practically zero heat! My reference lists serrano peppers at ~20k Scoville Heat Units, and jalapeño peppers at ~5k SHU, so I was expecting a good burn. What could have caused this awful lack of heat? I've heard growers are experimenting with breeding no-heat jalapeños for Americans, are they abusing the serrano crop the same way?