Brewhouse Efficiency and Grain Bill
Computes brewhouse efficiency in point-gallons at the kettle and the fermenter.
Example
You enter
- Grain weight (lb) 542
- Extract potential (points per lb per gal) 37
- Kettle volume (gal) 310
- Measured original gravity 1.055
- Kettle and whirlpool losses (gal) 15
- Stronger grain bill to compare (lb) 850
- Efficiency the recipe assumes (%) 85.02
- Efficiency actually achieved (%) 75
You get
- Efficiency at the kettle 85.0% of 20054 point-gallons available
- Efficiency at the fermenter 80.9066
- Assumed og points 86.2542
- Achieved og points 76.0887
- Extract short of the assumption 3151.29
- Total extract left in the tun 7862.5
- Shortfall malt equivalent (lb) 85.17
- Malt to add to make up the shortfall 113.56
Details, formula, and sources
Computes brewhouse efficiency in point-gallons at the kettle and the fermenter, then the gravity a stronger grain bill reaches. The worked brew is 85.0% at the kettle and 80.9% at the fermenter from the same day. At 850 lb, 75% efficiency lands 1.076 against the 1.086 the recipe assumed; making up the shortfall takes 114 lb of malt.
efficiency = gravity points x volume / (grain lb x extract potential); OG points = grain x potential x efficiency / volume; malt to recover = shortfall point-gallons / (potential x achieved efficiency).
Extract bookkeeping in point-gallons, with base malt near 37 points per pound per gallon. The malt supplier's certificate of analysis and the brewery's own measured gravities govern.
Public arithmetic; the extract potential comes from the malt analysis.
Estimate. AHJ and licensed professional govern.
Field names used by the API: grain_weight_lb, extract_potential_ppg, volume_gal, original_gravity, transfer_loss_gal, strong_grain_weight_lb, assumed_efficiency_pct, achieved_efficiency_pct, kettle_efficiency_pct, fermenter_efficiency_pct, assumed_og_points, achieved_og_points, shortfall_point_gallons, total_left_point_gallons, shortfall_malt_equivalent_lb, malt_to_recover_lb
- Measurement point the volume's point (kettle or fermenter) must be stated with the figurespec-v1778