Beer IBU Calculator

You swapped the hop variety, pushed the batch from 20 to 23 liters, and now you cannot tell whether the IPA lands balanced or harsh. Bitterness is the one thing tasting will not settle in advance, because sweet wort masks it. Four numbers go in here: grams of hops, the alpha acid printed on the bag, batch volume and boil time. 30 g at 8% in 20 L boiled for 60 minutes gives 27.7 IBU.

Under the hood sits the Tinseth equation: utilization is a gravity factor multiplied by a boil-time factor, and IBU works out as grams times alpha acid times utilization times ten, divided by liters. What the screen does not tell you is that gravity is hard-coded at 1.050 inside the math, so there is no OG field. The model also covers a single hop addition at a single boil time.

With a denser wort, say 1.075 on an imperial stout, real utilization drops and this figure reads high, so trim 10 to 15% off. A recipe with three additions means three runs, one per boil time, adding the IBUs at the end. Enter the finished batch volume, not the full kettle. Whirlpool and dry hop additions sit outside the model entirely. Everything runs in your browser and updates as you type.