Short answer: every number a brewing app gives you — strike temperature, IBU, ABV, pitching rate, priming sugar, colour, efficiency — is plain arithmetic you can build in one Excel sheet with no add-ins. Below are 20 advanced brewing calculations as ready-to-paste formulas with worked examples, organised across the brew day. Set up the cells once and you have a brewhouse calculator you fully understand.

Brewing software hides the maths. That’s fine until you need to tweak a recipe at 6 a.m., reconcile an efficiency miss, or explain a carbonation set point to a new brewer. A spreadsheet you built yourself does all of it and shows its working. If you are still talking yourself into the idea, collecting the data first is the right instinct — these formulas are what turn those numbers into decisions.

A convention for the whole article: cell references like B2 are examples — put your input in that cell and paste the formula next to it. Gravities are specific gravity (e.g. 1.050) unless stated; “points” means the last three digits ((SG − 1) × 1000), so 1.050 = 50 points. Spellings are British (colour, litres); imperial and metric notes are given where the constant changes.

The brew day, by the numbers — where each calculation lands RECIPE 1 · SG ↔ °Plato 2 · OG from grist 3 · Efficiency 12 · Colour SRM MASH 5 · Strike temp 6 · Step infusion 7 · Liquor:grist 9 · Water salts BOIL 8 · Boil-off 10 · IBU (Tinseth) 11 · Hop sub FERMENT 13 · Pitch rate 14 · Attenuation 4 · Temp correct 15 · Refractometer PACKAGE 16 · ABV 17 · Carbonation 18 · Blend/dilute 19 · Calories COST 20 · COGS / hL & cost per pint
The 20 calculations, mapped to the stage where you use them. Numbers below match this map.

Recipe and gravity

1. Convert specific gravity to °Plato. Brewers and instruments disagree on scale; convert without a lookup table. Formula: °P ≈ 259 − (259 ÷ SG). Excel (SG in B2): =259-(259/B2). Reverse (Plato → SG): =259/(259-B2). Example: SG 1.048 → =259-(259/1.048) = 11.9 °P.

2. Predict original gravity from the grain bill. Know your OG before you brew. Formula: points = Σ(weight × PPG) × efficiency ÷ volume; OG = 1 + points ÷ 1000. PPG is points-per-pound-per-gallon (≈ 37 for pale malt). Excel (weights in B2:B6, PPGs in C2:C6, efficiency in F2, post-boil gallons in G2): =1+(SUMPRODUCT(B2:B6,C2:C6)*F2)/(G2*1000). Example: 10 lb pale malt (PPG 37) at 75% into 5.5 gal → 1.050.

3. Brewhouse and mash efficiency. The single number that explains why your OG missed. Formula: efficiency = (measured points × volume) ÷ maximum possible points. Excel (OG in B2, gallons collected in B3, total potential points Σ(lb × PPG) in B4): =((B2-1)*1000*B3)/B4*100. Example: OG 1.050, 5.5 gal, 370 potential points → 74%.

4. Hydrometer temperature correction. A warm sample reads low; correct it instead of guessing. Formula: a cubic in sample temperature relative to the hydrometer’s calibration temperature (°F). Excel (measured SG B2, sample temp °F B3, calibration temp °F B4): =B2*((1.00130346-0.000134722124*B3+0.00000204052596*B3^2-0.00000000232820948*B3^3)/(1.00130346-0.000134722124*B4+0.00000204052596*B4^2-0.00000000232820948*B4^3)). Example: 1.050 read at 100 °F, calibrated at 60 °F → 1.056.

Mash and water

Hot liquor Tw ≈ 164 °F (what you heat to) + Grain T1 = 65 °F (specific heat ≈ 0.2) Mash tun T2 = 152 °F target (what you want) Tw = (0.2 ÷ R)(T2 − T1) + T2 → heat the water hotter to absorb the grain's cold mass
Strike-water heat balance (use case 5): the water must run hot enough that cool grain pulls the mix down to target.

5. Strike (mash-in) water temperature. Heat the liquor hot enough that cold grain lands you on target. Formula: Tw = (0.2 ÷ R)(T2 − T1) + T2 — R = water:grain in qt/lb, T1 = grain temp, T2 = target mash temp (°F). Excel (R in B2, grain temp in B3, target in B4): =(0.2/B2)*(B4-B3)+B4. Example: R = 1.5 qt/lb, grain 65 °F, target 152 °F → 163.6 °F. Metric (L/kg, °C): replace 0.2 with 0.41.

6. Step-mash infusion (boiling water addition). How much boiling water raises the mash to the next rest. Formula: Wa = (T2 − T1)(0.2·G + Wm) ÷ (Tw − T2) — G = grain (lb), Wm = water already in mash (qt), Tw = 212 °F. Excel (G B2, current temp B3, target B4, mash water B5, infusion temp B6): =(B4-B3)*(0.2*B2+B5)/(B6-B4). Example: 10 lb, 152→168 °F, 15 qt in mash, 212 °F water → 6.2 qt.

7. Liquor-to-grist ratio (mash thickness). Thin mashes favour fermentability; thick mashes protect enzymes. Formula: ratio = water ÷ grain. Excel (water B2, grain B3): =B2/B3. Convert qt/lb → L/kg with =B2/B3*2.086. Example: 15 qt ÷ 10 lb = 1.5 qt/lb (≈ 3.13 L/kg).

8. Pre-boil volume and boil-off. Hit your post-boil volume by starting with the right pre-boil. Formula: pre-boil = target post-boil + (evaporation rate × boil hours); add ~4% for cooling shrinkage. Excel (target post-boil litres B2, evap L/hr B3, hours B4): =(B2/0.96)+B3*B4. Example: 23 L target, 4 L/hr, 1 hr → ≈ 28 L pre-boil.

9. Water chemistry — residual alkalinity and sulfate:chloride. Two numbers that decide mash pH and hop character. Formulas: RA = alkalinity − (Ca ÷ 3.5 + Mg ÷ 7), all as ppm; SO₄:Cl = sulfate ÷ chloride. Excel (alkalinity as CaCO₃ B2, Ca B3, Mg B4, sulfate B5, chloride B6): RA =B2-(B3/3.5+B4/7), ratio =B5/B6. Salt additions (per gram per gallon): gypsum adds 61.5 ppm Ca + 147.4 ppm SO₄; calcium chloride adds 72 ppm Ca + 127.4 ppm Cl. New level: =base_ppm + grams_per_gal*61.5. Example: alkalinity 100, Ca 50, Mg 10 → RA 84 ppm; SO₄ 150, Cl 50 → 3.0 (hop-forward).

Boil and hops

Hop utilisation vs boil time (Tinseth) 0306090 Boil time (minutes) Utilisation most bitterness locked in by ~60 min
Why a 90-minute addition isn't much more bitter than a 60-minute one (use case 10).

10. IBU by the Tinseth method. The industry-standard bitterness estimate, in two cells. Formulas: utilisation = (1.65 × 0.000125^(OG−1)) × ((1 − e^(−0.04·t)) ÷ 4.15); IBU = utilisation × (AA% × grams × 1000 ÷ litres). Excel (AA% B2, grams B3, boil min B4, litres B5, OG B6): utilisation in B7 = =(1.65*0.000125^(B6-1))*((1-EXP(-0.04*B4))/4.15); IBU = =B7*((B2/100)*B3*1000)/B5. Example: 28 g at 6.4% AA, 60 min, 23 L, OG 1.050 → ≈ 18 IBU.

11. Hop substitution by alpha acid. Out of stock? Match the bitterness, not the weight. Formula: new weight = (original weight × original AA%) ÷ new AA%. Excel (original grams B2, original AA% B3, substitute AA% B4): =(B2*B3)/B4. Example: recipe wants 28 g at 6.4%; you have 9.2% AA hops → 19.5 g.

12. Beer colour (SRM and EBC). Estimate the glass before you mash. Formulas: MCU = Σ(grain °L × weight lb) ÷ gallons; SRM = 1.4922 × MCU^0.6859 (Morey); EBC = SRM × 1.97. Excel (°L B2:B3, weights C2:C3, gallons D2): MCU E2 = =SUMPRODUCT(B2:B3,C2:C3)/D2; SRM F2 = =1.4922*E2^0.6859; EBC = =F2*1.97. Example: 9 lb pale (3 °L) + 1 lb crystal (60 °L) in 5.5 gal → MCU 15.8 → ≈ 10 SRM / 19 EBC (amber).

Yeast and fermentation

13. Yeast pitching rate. Under-pitching is the most common avoidable fault; size it. Formula: billion cells = pitch rate (M cells/mL/°P) × volume (L) × °Plato. Rate ≈ 0.75 for ales, 1.5 for lagers. Excel (rate B2, litres B3, °P B4): cells =B2*B3*B4; packs at 100 B each =B2*B3*B4/100. Example: ale at 0.75, 23 L, 12 °P → 207 billion cells ≈ 2 fresh packs or a starter.

14. Apparent and real attenuation. How far the yeast actually went. Formulas: apparent = (OG − FG) ÷ (OG − 1) × 100; real ≈ apparent × 0.81 (true real degree uses real extract from Plato). Excel (OG B2, FG B3): apparent =(B2-B3)/(B2-1)*100; real =(B2-B3)/(B2-1)*100*0.81. Example: 1.050 → 1.010 → 80% apparent / ≈ 65% real.

15. Refractometer final-gravity correction. Refractometers lie once alcohol is present; this fixes it. Formula: Terrill cubic in initial and final Brix (divide each reading by your wort correction factor, ~1.04, first). Excel (corrected initial Brix B2, corrected final Brix B3): =1.0000-0.0044993*B2+0.011774*B3+0.00027581*B2^2-0.0012717*B3^2-0.00000728*B2^3+0.000063293*B3^3. Example: 12.5 → 6.0 Brix → FG ≈ 1.011.

16. ABV from gravity. The headline number, two ways. Formulas: simple = (OG − FG) × 131.25; more accurate (stronger beers) = (76.08 × (OG − FG) ÷ (1.775 − OG)) × (FG ÷ 0.794). Excel (OG B2, FG B3): simple =(B2-B3)*131.25; accurate =(76.08*(B2-B3)/(1.775-B2))*(B3/0.794). Example: 1.050 → 1.011 → 5.1% (simple) / 5.2% (accurate).

Packaging and finishing

Pearson's square — blend to a target TARGET 5.0% A: 6.5% B: 3.0% parts A = 5.0−3.0 = 2.0 parts B = 6.5−5.0 = 1.5 Blend 2.0 : 1.5 (A : B) → 5.0% ✓
Pearson's square (use case 18): each corner subtracts diagonally to give the blend ratio.

17. Priming sugar for bottle carbonation. Hit a target CO₂ without bottle bombs. Formulas: residual CO₂ (vols) = 3.0378 − 0.050062·T + 0.00026555·T² (T = highest temp the beer saw, °F); corn sugar (g) = (target vols − residual) × litres × 4.0. Excel (max temp °F B2, target vols B3, litres B4): residual B5 = =3.0378-0.050062*B2+0.00026555*B2^2; sugar = =(B3-B5)*B4*4.0. Example: 68 °F, target 2.4 vols, 23 L → residual 0.86 → ≈ 141 g corn sugar. (Table sugar: × 0.91.)

18. Blend or dilute to a target. Trim a high-gravity wort with water, or marry two beers to a number. Dilution formula: water to add = volume × (current points − target points) ÷ target points. Excel (volume B2, current points B3, target points B4): =B2*(B3-B4)/B4. Example: 25 L at 1.060 (60 pts) down to 1.050 (50 pts) → add 5 L water. For blending two finished beers to a target ABV, use Pearson’s square above: parts = the diagonal differences.

19. Calories per serving. A label number marketing always asks for. Formulas (per 12 oz / 355 mL): alcohol cal = 1881.22 × FG × (OG − FG) ÷ (1.775 − OG); carbohydrate cal = 3550 × FG × ((0.1808 × OG) + (0.8192 × FG) − 1.0004); total = sum. Excel (OG B2, FG B3): alcohol =1881.22*B3*(B2-B3)/(1.775-B2); carbs =3550*B3*((0.1808*B2)+(0.8192*B3)-1.0004); scale by serving size from 355 mL. Example: 1.050 → 1.011 → ≈ 102 (alcohol) + 64 (carbs) = ≈ 166 cal per 12 oz.

Costing

20. Cost of goods per hectolitre and per pint. Where recipe maths meets the P&L. Formulas: COGS/hL = total batch cost ÷ batch volume (hL); cost/pint = COGS/hL × 0.00568 (a UK pint is 0.568 L; 1 hL = 100 L). Excel (total batch cost B2, batch hL B3): COGS/hL B4 = =B2/B3; cost/pint = =B4*0.00568. Example: £450 batch, 10 hL → £45/hL ≈ £0.26 per pint. Build it up properly with the method in cost of goods per hectolitre.

The bottom line

These 20 formulas cover the brew day end to end: recipe design, mash and water, boil and hops, fermentation, packaging and cost. None needs an add-in — paste them into one sheet, label your input cells, and you have a brewhouse calculator that shows its working and that you can audit line by line. Keep the inputs honest (weigh, measure, record) and the maths will be right every time; that discipline is also exactly what makes the jump from brewer to data scientist a short one when you’re ready for it.

Frequently asked questions

Can you calculate ABV in Excel? Yes. The standard formula is =(OG-FG)131.25, where OG and FG are your original and final specific gravities. For higher-strength beers a more accurate version is =(76.08(OG-FG)/(1.775-OG))*(FG/0.794). Both work in any version of Excel with no add-ins.

What is the Excel formula for mash strike water temperature? Strike temp Tw = (0.2/R)(T2-T1)+T2, where R is the water-to-grain ratio in quarts per pound, T1 is grain temperature and T2 is your target mash temperature in °F. In Excel: =(0.2/B2)*(B4-B3)+B4 with R in B2, grain temp in B3 and target in B4. For metric (L/kg, °C) swap the 0.2 for 0.41.

Do I need special brewing software to do these calculations? No. Every calculation here — gravity, efficiency, IBU, colour, pitching rate, carbonation, ABV — is just arithmetic that brewing software runs under the hood. A single Excel sheet with these formulas reproduces it, and because you can see every cell you understand and trust the result.

Part of the Brewing Science & AI track.