Beer Brewing
Why Did My Beer Finish at a Higher Gravity?
Troubleshoot a beer that finishes sweeter or denser than expected by checking the recipe, mash, yeast, and readings.
Check the measurement first
A higher-than-expected final gravity (FG) can reflect the beer, the recipe, or the measurement. Check that the sample is degassed, the hydrometer is read at eye level, and the reading is corrected for the instrument’s calibration temperature.
If using a refractometer after fermentation, account for alcohol with a validated correction. Raw post-fermentation Brix does not directly equal specific gravity.
Review fermentability and fermentation conditions
A mash that favors more unfermentable extract, a recipe with specialty malts, yeast strain, pitching health, and fermentation temperature can all affect attenuation. These are possibilities to investigate, not proof of a fault.
Compare your actual mash temperature, yeast instructions, and fermentation log with the recipe. Check whether gravity is still changing over repeat measurements before deciding the beer is finished.
Worked example: calculate apparent attenuation
If a beer starts at OG 1.060 and finishes at FG 1.018, apparent attenuation is ((1.060 − 1.018) ÷ (1.060 − 1.000)) × 100 = 70%. This describes the gravity drop; it does not identify why fermentation stopped at that point or whether the beer tastes too sweet for its style.
Make one change at a time
Record the current batch, compare it with prior brews, and change one process variable on the next batch. Avoid adding more fermentables or packaging based on a single unexpected reading.
The beer ABV calculator estimates alcohol from OG and FG; the specific gravity guide covers reliable readings.