Expected attenuation depends entirely on which strain you pitched — there's no single "normal" percentage across yeast, and the range across commercially available strains is wide enough that a generic rule of thumb ("shoot for 75%") is actively misleading for a meaningful share of them.
The real spread across common strains
- Clean American ale strains (Fermentis US-05, Wyeast 1056, White Labs WLP001): typically 73-80% — the range most homebrewers implicitly assume is "normal," because it's the most widely used strain family.
- English ale strains run noticeably lower and are supposed to — White Labs WLP002 is rated 63-70%, leaving more residual sweetness and body by design, not by underperformance. Judging an English-strain batch against an American-strain expectation is a common source of unnecessary worry.
- Lager strains (Fermentis W-34/70): typically 80-84%, on the higher side.
- High-attenuating specialty strains: French saison strains like Wyeast 3711 are rated 78-85%, some kveik strains run similarly high, and wine yeasts used for high-gravity mead or cider (Lalvin EC-1118) can finish above 90% on a fermentable must.
Check your exact strain's published range on the yeast reference before assuming any number is "supposed to" apply — the spread between a low-attenuating English strain and a high-attenuating saison strain is wide enough to completely change what a "normal" FG looks like from the identical OG.
Turning a published range into an expected FG
A manufacturer's attenuation range applies to your actual OG, not to a fixed FG. At the midpoint of its published 75-82% range, Fermentis S-04 on a 1.050 OG wort lands around 1.011 FG (roughly 5.15% ABV) — check this exact example. The same strain on a 1.070 OG wort finishes at a proportionally different FG, since attenuation is a percentage of the OG's own extract, not a fixed point drop — see why is my final gravity stuck at 1.020 if your actual result sits well below the range your strain's data sheet publishes.
Why real-world results still vary within the published range, or outside it
Manufacturer ranges are the strain's typical performance under reasonably good conditions — real results still shift with pitch rate, aeration, fermentation temperature, and wort composition (a highly fermentable wort pushes attenuation toward the top of a strain's range; a less fermentable one, produced by a higher mash temperature, pushes it lower even with an identical strain). A result meaningfully below even the low end of a strain's published range, after ruling out a genuine stall, usually points to underpitching, poor aeration, or a fermentation temperature that ran too cold for that particular strain — check the strain's published temperature range on the yeast reference alongside its attenuation figure, since the two are connected.