Water hot chilli peppers

If you have bitten unsuspecting into a Mexican pizza to find that a red hot chilli pepper was nestling there under the mozzarella, then you will no doubt have found yourself reaching for a glass of water to quench the fires that are dancing along your tongue. Wise veterans of oral chilli wildfires often counsel that water is of no help and that milk is the flame retardant of choice in these circumstances. We leave conclusions on that point to the expert folk at the Oral Fire Service but today we turn to the paradoxical fact that were it not for water, chillies would not possess their heat.

From 2002 to 2009 researchers studied the qualities of chillies that grow in different climates. They found that chillies with less heat tend to grow in areas where there is little water available. By contrast, hot chillies seem to do well in well watered areas.

The theory goes that in dry areas the chillies need what water they can find in order to live and do not devote the precious resource to producing the “capsaicinoids” that give chilli its spicy heat. In wet areas however, where water is not an issue those plants that produce more capsaicinoids do well as these compounds kill the fungi that live on the fruit in wet areas. Additionally, the capsaicinoids keep rats from eating the fruit. So where the cost is not too high to produce them, the spicy chilli compounds give the plants an advantage.

The researchers followed up this observational study with some lab-based work and found that spicier chilli plants produce 50 per cent fewer seeds if they are starved of water. Less hot plants however, were not affected by water deprivation. Spicier plants were also found to have 40 per cent more stomata (holes that allow water in and out of the plant) and this could account for their water loss and difficulty dealing with dry conditions.

The end result is that the more water available to the plant; the spicier the chillies that the plant produces.

This property of chillies of course, is behind the naming of the alternative food science rock band The Water Hot Chilli Peppers, a band so successful that the founding members Anthony Aquaduct and Mark “Fruit Fly” Topiary are still with the band more than two decades after its inception.