I grew some chilli's for the first time this year and I had a substantial crop.But some of the chilli's are tasteless and some are really hot. Why would this happen when they all came off the same plant ?.
It's possible the peppers were picked from opposite sides of the same plant. By that I mean, peppers grown in shady areas are cooler in capsacacin content than peppers grown in full sun. Additionally, were you growing other peppers nearby? Cross-pollination can cause peppers to be hot or mild.
Fetilization with high nitrogen fertilizer will cool the plant down substantially since that encourages foilage growth...