IBU by hop weight
IBU for 1 oz of 10% alpha hops at 15 minutes
One ounce of 10% alpha acid hops boiled for 15 minutes in 5 gallons at 1.050 gives 17.1 IBU by Tinseth and 12.3 IBU by Rager.
Utilisation rises steeply early in the boil and flattens out after about 45 minutes, which is why a 90 minute addition is not worth much more bitterness than a 60 minute one.
1 oz at 10% alpha, 15 minute boil, 5 gallons
| Model | IBU | Basis |
|---|---|---|
| Tinseth | 17.1 | Standard |
| Rager | 12.3 | Standard |
| Difference | -4.8 | Standard |
Rows marked Standard come from a published equation, constant or manufacturer specification. Rows marked Convention are widely repeated brewing practice with no governing document behind them. The difference matters, so this site labels it rather than blurring the two together.
Hops and hop handling gear
Prices are those returned when this page was last built and change often.
Cascade Pellet Hops (1 lb)
A pound of Cascade pellets, the classic American aroma hop, which is far cheaper per ounce than small packets.
Centennial Hop Pellets (8 oz)
Half pound of Centennial, a dual purpose American hop.
BSG Mosaic Hop Pellets (8 oz)
Half pound of Mosaic, a high impact aroma hop for dry hopping.
BSG Magnum Hop Pellets (8 oz)
High alpha bittering hop, which delivers a given IBU from a smaller weight of hops.
Citra Pellet Hops (1 oz)
Single ounce of Citra, the usual quantity for one late or dry hop addition.
YCH Citra Hop Pellets (1 lb)
A full pound of Citra for brewers dry hopping heavily and often.
TIZZE Hop Spider (300 micron)
Stainless mesh basket that keeps hop matter out of the wort, which makes transfer far cleaner.
TIZZE 4 x 10 inch Hop Spider
Four by ten inch 300 micron hop filter that hangs in the kettle.
Hop Hopper Spider Strainer Basket (6 x 14 inch)
Larger hop basket for heavily hopped ten gallon batches.
Digital Pocket Scale 200 g x 0.01 g
Hundredth of a gram resolution, which is the precision hop additions and water salts actually need.
BOMATA 1 kg x 0.01 g Digital Scale
Wider range 0.01 g scale, which covers both salt additions and whole hop packets.
Bonvoisin Digital Lab Scale 600 g x 0.01 g
Laboratory balance with a draft shield style body, for brewers building water profiles by the tenth of a gram.
Related on BrewGearCalc
- IBU calculator
- How to build a hop schedule
- IBU for 1 oz of 10% alpha hops at 20 minutes
- IBU for 1 oz of 10% alpha hops at 10 minutes
- IBU for 1 oz of 10% alpha hops at 30 minutes
- IBU for 2 oz of 14% alpha hops at 60 minutes
- IBU for 0.5 oz of 12% alpha hops at 60 minutes
- IBU for 1.5 oz of 10% alpha hops at 60 minutes
Frequently asked questions
- How much bitterness does a 15 minute hop addition actually contribute?
- At 15 minutes, one ounce of 10% alpha hops in 5 gallons contributes 17.1 IBU by Tinseth. Utilisation climbs quickly for the first half hour and then flattens, so most of the bitterness in a 60 minute addition was already extracted well before the hour was up.
- Is a 60 minute boil actually necessary?
- The 60 minute boil is convention rather than a published requirement. It persists because it gives reliable hop utilisation, drives off unwanted volatiles from pale malt, and gives a predictable boil-off volume. Shorter boils work for many beers, and some brewers go longer for specific styles.
Researched from published brewing formulas, manufacturer specifications and verified owner reviews. This is general guidance, not professional advice.