Have you noticed how the indicators on hot sauce bottles (usually a little thermometer) are all different? Some say they're flaming hot and turn out to be mild and then the ones that are truly hot surprise you! Let's put a stop to that and come up with a standard.
The "spicy heat" of chili peppers is scientifically referred to as pungency. The most common method of measuring is by using the well established Scoville Heat Unit (SHU) scale. You can read about it on Wikipedia.
Using this scale, a relationship can be made between SHU and to what most people can realistically handle, or better yet, enjoy. This is an approximating scale until capsaicinoid concentrations can be more accurately determined. Additionally, there are seven types of capsaicinoids, so the SHU scale points directly to the different type of peppers used, thus addressing the capsaicinoids within the different types of peppers. In most cases, this is irrelevant because capsaicin is the most potent out of all of the capsaicinoids and dominates the others, rendering them insignificant.
SHUR stands for Scoville Heat Unit Realistic: a standardized pungency (spicy heat) rating scale for hot sauce.
The SHUR scale ranges from 0 to 10. A rating of 0 indicated no spice and a rating of 10 represents a concentration of a pepper rated at 25,000 SHU, which is like eating a whole Thai chili pepper.
You can generate your own SHUR rating for your hot sauces. Simply download the Excel spreadsheet and enter the bottle size, chili pepper amount used, and SHU rating for that pepper.
This graph illustrates how the SHUR (0-10) values match SHU values (0 to 100,000).