ABV: strength
Alcohol by volume is the percentage of the beer that is alcohol. A typical pilsner sits near 5 percent, an IPA 6 to 7 percent, a double IPA or imperial stout 8 to 12 percent or more. Strength affects body and warmth, and it matters for pacing.
IBU: bitterness, with a caveat
International Bitterness Units estimate the concentration of bitter compounds, mostly from hops boiled in the wort. A light lager might be 10 to 20 IBU; a West Coast IPA 50 to 70 or more. But malt sweetness, body and carbonation change how bitter a beer tastes. A 60-IBU imperial stout can taste less bitter than a 40-IBU pilsner. Above roughly 100 IBU, people generally cannot detect further differences.
SRM: color
The Standard Reference Method measures how much light a beer absorbs. Low numbers are pale straw and gold; around 10 to 17 is amber and copper; 20 to 30 is brown; 35 and above is near black. Color comes from malt, and darker malts often add toast, caramel, chocolate or coffee flavors, but color alone does not predict weight or strength.
Why the Guide does not invent numbers
Producers do not always publish ABV or IBU, and recipes change between releases. When a figure has not been verified for the referenced release, the Guide marks it “To verify” rather than estimating. Style profiles show typical ranges for the style, clearly labeled as such.
Questions people ask
Is a higher IBU always more bitter?
Not always. Malt sweetness and body can balance bitterness, so two beers with the same IBU can taste quite different.
Do dark beers have more alcohol?
Not necessarily. Many dark lagers and dry stouts are around 4 to 5 percent ABV.
What is OG or original gravity?
A measure of sugars in the wort before fermentation. Brewers use it to estimate alcohol and body.