Hop stands avoid vaporizing the essential oils and are said to result in smoother bitterness and flavor. The temperature and time of the exposure greatly impacts the utilization (for the purposes of IBU calculations). Given the wide variation in process and equipment out there, the utilization factor is left up to the brewer. A value of 10% is generally accepted, but could vary based on process. The hotter the temperature and the more time, the higher the utilization.
When selecting Whirlpool or Hopback as the hop use, two new fields will appear.