Scoville Heat Units (SHU) are used to measure what aspect of capsicum?

Scoville Heat Units (SHU) are a standardized measure used to quantify the heat or spiciness of capsicum peppers, which includes various types of chili peppers. The scale was developed by pharmacist Wilbur Scoville in 1912 and is based on the concentration of capsaicin, the chemical compound responsible for the heat sensation in peppers.

When measuring the heat value, SHU allows for a comparison of the spiciness of different peppers. A higher SHU indicates a greater concentration of capsaicin, resulting in a hotter pepper. For instance, a bell pepper would have a SHU of 0, while a habanero can range from 100,000 to 350,000 SHU, demonstrating significantly higher heat levels.

The other options relate to different characteristics of physical substances, such as weight, volume, and concentration, but none of them specifically address the measurement of heat, which is the primary purpose of the Scoville Heat Unit system.