What is the BU:GU ratio?

The BU:GU ratio compares IBU (Bitterness Units) to GU (Gravity Units, where GU = (OG-1) x 1000). It indicates how bitter a beer will taste relative to its malt sweetness. A ratio of 0.5 is malty, 0.8 is balanced, and 1.0+ is hoppy.

What ratio should I target?

Common targets: English Bitter 0.6-0.8, American Pale Ale 0.7-0.9, IPA 0.8-1.2, Stout 0.5-0.8, Wheat Beer 0.3-0.5, Barleywine 0.6-0.9. The ratio helps maintain balance regardless of beer strength.

Does the ratio account for real perceived bitterness?

The BU:GU ratio is a useful guideline but does not account for all factors affecting perceived bitterness. Water chemistry (chloride vs sulphate), residual sweetness (FG), carbonation level, and serving temperature all affect how bitter a beer tastes.

What about the RBR (Relative Bitterness Ratio)?

RBR is a more refined balance metric that accounts for final gravity: RBR = BU / (OE - RE), where OE is original extract and RE is real extract. It gives a better indication of perceived bitterness because it factors in residual sweetness. Values above 1.0 indicate hop-forward beers.

How does water chemistry affect perceived balance?

Sulphate-rich water accentuates hop bitterness, making the beer taste more bitter at the same IBU. Chloride-rich water enhances malt sweetness and fullness. The sulphate-to-chloride ratio is as important as IBU for perceived balance in hop-forward beers.

BrewCalcs

Bittering Ratio Calculator — BU:GU

Calculate the BU:GU ratio to assess the balance between bitterness and malt sweetness.

IBU

Original Gravity

How We Calculate This

The BU:GU Ratio

BU:GU = IBU / ((OG - 1) x 1000)

GU (Gravity Units) are simply the last two digits of the OG. For example, OG 1.050 has 50 GU. If the beer has 40 IBU, the ratio is 40/50 = 0.80, indicating a balanced beer.

Frequently Asked Questions

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First Wort Hop Calculator

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Last updated: 2025-02-20

All calculations are estimates. Always verify values and adjust based on your equipment and ingredients.