Hop Weight Calculator (for a required level of IBUs)
Replacement Hop Calculator (for hops of different AA% content)
The level of bitterness of a beer is calculated in IBUs (international bittering units) also known as EBUs (European bittering units).
Individual varieties of hop have provide different levels of bitterness per unit of weight, this is measured by Alpha Acid content. Same varieties also vary from year to year.
Utilization is a way of measuring the extraction of bitterness from the hops in a recipe.
Utilization varies with the vigor of the boil, the volume of the boil, the gravity of the boil and the duration of the boil.
After a typical boil duration of 90 mins, utilization will be around 30% for a low gravity (1030) wort and around 23% for a high gravity (1060 wort).
After a boil duration of 60 mins, utilization will only be slightly less at around 28% for a low gravity (1030) wort and around 21% for a high gravity (1060 wort).
For an average gravity wort utilization will be around 27% during a 90 min boil and around 25% for a 60 min boil. These figures can be adjusted with experience and should be only used as a guide..
Use
this calculator to
estimate the IBUs (or bitterness) of a particular recipe.
(if more than one hop is used or multiple additions are used then
calculate the hop additions separately then add the results together to give
total IBUs)
Stronger, higher gravity beers require a higher level of bitterness to balance out the sweet malt flavours.
When designing a recipe a rule of thumb is that IBUs/OG should equal 1 or less to avoid excessive bitterness.
If a particular hop isn't available or a replacement hop is to be used in a recipe, the weight of hops should be adjusted to allow for different alpha acid contents.