Peppers for Chilli Jam

Our answer

The long red chillies used in Nigella's Chilli Jam (from Christmas and on the Nigella website) are often known as Dutch chiliies. They are what could be considered a "medium heat". There is a scale known as the Scoville scale and this measures the "hotness" of a chilli pepper, defined by the concentration of capsaicin in the chilli. The hotter the chilli, the higher the Scoville rating (Scoville Heat Units or SHU).

Dutch chillis have a rating of between 3,500 and 8,000 SHU. We suspect that the small red chillies you describe are Thai Bird's Eye Chillies. These are rated at about 100,000 SHU. However as the rating system is slightly subjective it means that the Bird's Eye chillies are a lot hotter than the Dutch ones, but it does not mean that you would use less than 1/10th of a Bird's Eye chilli to replace one Dutch chilli. We would suggest if possible trying to use the Dutch chillies, or an alternative with a similar heat rating such as red jalapeno chillies. If you have to use some hotter chilles then maybe try 75g of the Bird's Eye chilles and 225g red bell peppers (or bell sweet pointed peppers), though we have not tried this combination ourselves so can't guarantee the results.