One of the most popular questions about the chilli is which is the hottest, the spiciest, the most pungent chile pepper. It is easy to answer – and difficult to answer.
The easy way is to look in the Guiness Book of World Records for the officially declared winner in this category.

Since 2017, the Guiness World Record for hottest chilli pepper has been held by the Carolina Reaper from Ed Currie of PuckerButt Pepper Company (USA). It rates an average of 1,641,183 Scoville Heat Units (SHU; the scientific measure of how hot a chilli is because of the amount of capsaicin it contains).

Not everyone submits their chilli to the Guiness Book of World Records, however. (Doing so costs a lot.) For such records, the pungency of the chilli also needs to be measured scientifically, by letting a laboratory perform high performance liquid chromatography to determine the capsaicin content of the submitted material, then calculate the Scoville Heat Units from that.

The quality of those tests has sometimes been put into question when new record pungency was announced, so this would ideally also need to be confirmed.
It is all expensive and complicated – and to a normal person, it may not matter quite so much.

When you grow the record-hot chile peppers, you should find them to have a very high pungency.

First, though, you need to have found seeds which really are of that record variety and not crossed with something else (or something else entirely).

And then, secondly, the pungency produced can still vary with the growing conditions, so that it may turn out lower than the record. (That is why it is important that the Guiness Book has looked at the average Scoville Heat Units, not the maximum.)

Finally, for actually using the chilli in eating rather than industry, record-high hotness does not really matter. In fact, it may easily hurt.

One thing that can be said about the record-holding chilli, though: The hottest chilli can definitely be found among the species Capsicum chinense.

Among this species, which includes the well-known habanero, chile growers now talk of a new category, the “superhots.”