- How do I know how much hop to use?
Many brewers add hops at 15 or 20 minute intervals and usually in multiples of a half ounce (for ease of measurement). 75 is a constant for the conversion of English units to Metric. The proper units for IBUs are milligrams per liter, so to convert from ounces per gallon a conversion factor of 75 (74.89) is needed.

- How do you calculate hop utilization?
From a formulaic or mathematical point of view, hop utilization breaks down accordingly: %U(utilization) = (isoalpha acids presentÂ¸ alpha acid used) x 100.