Background and Research


Chile peppers are becoming more popular in the United States due to the fact that more people are using them in their cuisine or as decorations for their homes.  The chile pepper’s pungency is designed for protection against mammals trying to eat them.  Mammals are the only living things who can feel the heat of the capsaicinoids which make the peppers hot.  The main reason why we are interested in doing research on this specific subject is because we have been living in Hatch, New Mexico all of our lives.  Chile is an important part to Hatch’s economy and lifestyle.  We, like the majority of the world, wonder what makes a chile hot.  As chile continues to grow more popular in our society, people want to know how the chile pepper gets its pungent taste and what factors contribute towards its pungent flavor. 

The pepper fruit contains many chemical compounds known as capsaicinoids which give the fruit its pungent flavor.  The most common components of this class are capsaicin and di-hydrocapsaicin.  Together they make up 75-85% of the capsaicinoids found in chile.  Capsaicinoids are not soluble in water, but they are very soluble in fats, oils, and alcohol.  Pure capsaicin is rated at 15-16,000,000 SHU, which stand for Scoville Heat Units; the units of measure that tell how hot a chile is.  “All capsaicinoids found in chiles are slightly different in their hydrocarbon tail.  This difference allows them to penetrate and bind to nerve receptors in the tongue, mouth, and throat.  This explains why some chiles burn in the mouth, while others burn deep in the throat,” (

Chile plants may become more or less pungent if they are stressed.  Two types of stress that affect the pungency of peppers are having a high average temperature outside, and insufficient watering.  Another form of stress is overwatering. It does not matter what type of stress the plant goes through; any type of stress will increase or decrease the pungency of the fruit.  This is one of the main reasons why the majority of farmers do not like to over water their crop. 

Many experts disagree on what factors affect chile.  There have been a lot of studies conducted on how the chile plant is affected by the different factors. One study, Pungency of Chile Fruit is affected by Node Position, talks about how the position of the node, the area of a plant's stem from which the leaves grow, and how it affects how pungent the chile will become (Zewdie 2000a).  This article also states that fruits grown on the second node, from the base up, will average a higher pungency than those on the fifth or sixth node.  Another study explains how the pungency of the fruits on a single plant can differ in their pungency levels (Kirschbaum-Titze 2002).  This means that out of all of the fruits on a chile plant most of them will not have the same pungency.  Fruits from one side of the plant may be under a different type of stressor than a fruit on the opposite side.  Other studies have demonstrated that the amount of capsaicinoids in the pepper fruit fluctuates as the fruit is maturing.  Some articles even suggest that “capsaicinoid production increases with maturity and then reaches a peak, followed by a rapid degradation of up to 60%” (Iwai 1979).  It is very difficult to try to model the amount of pungency in a chile pepper at a given time due to all of the factors that determine what the total pungency will be in the fruit.  However by conducting the appropriate type of research, we are able to create a program that may benefit farmers at the end of the season.  This way they do not have to rely on the seed variety alone to determine the pungency of their crop.