Tools in This Collection
IBU Calculator
Calculate International Bitterness Units from hop additions
SRM Color Calculator
Estimate beer color from grain bill in SRM or Lovibond
Brewing Water Calculator
Adjust water mineral profile for beer style targets
Strike Water Calculator
Calculate strike water volume and temperature for mash
Brewhouse Efficiency Calculator
Measure mash and total brewhouse efficiency
Boil-Off Calculator
Estimate wort volume loss during the boil
Beer Recipe Scaler
Scale recipes between different batch sizes
Designing a Beer Recipe: The Calculation Workflow
A beer recipe has four interdependent variables: bitterness (IBU), color (SRM), efficiency (how much sugar you extract from grain), and water chemistry (mineral profile). Getting all four right requires working through them in sequence. Start with the Beer Recipe Scaler if you're adapting an existing recipe — it proportionally adjusts all grain, hop, and water amounts for a different batch size before you do any chemistry calculations.
Bitterness and Color
The IBU Calculator calculates International Bitterness Units from your hop additions using the Tinseth formula (most widely used and matches commercial brewing databases). A West Coast IPA targets 60-80 IBU; an American light lager targets 8-12 IBU. Color follows from your grain bill: the SRM Color Calculator uses the Malt Color Units (MCU) method to estimate beer color in Standard Reference Method units. An American pale ale ranges 3-7 SRM (straw to gold); a stout runs 35+ SRM (near-black).
Water Chemistry
Water mineral profile profoundly affects hop and malt character. High sulfate (SO4) accentuates hop bitterness and dryness — the Burton-on-Trent water profile (275+ ppm sulfate) defines the classic English IPA style. High chloride (Cl) emphasizes malt softness and roundness — optimal for German lagers and English mild ales. The Brewing Water Calculator adjusts Ca, Mg, Na, SO4, Cl, and bicarbonate by adding salts (gypsum, calcium chloride, Epsom salt, baking soda) to your source water or a RO/distilled water base. Input your source water analysis and target style, and the calculator shows exactly what salt additions to make.
Mash Temperature and Efficiency
Before the mash, the Strike Water Calculator calculates how hot your strike water must be to hit target mash temperature. For a typical 1.25 qt/lb ratio with grain at 68°F targeting a 152°F mash: strike water temperature is about 164°F. Add water to the mash tun first, then add grain to prevent scorching. After brewing, the Brewhouse Efficiency Calculator works backward from your actual original gravity to show your efficiency percentage. Most homebrewers achieve 65-75% efficiency. The Boil-Off Calculator estimates post-boil volume given your pre-boil volume and evaporation rate — typically 1-1.5 gallons per hour for a propane burner outdoor setup.
Frequently Asked Questions
What IBU level should I target for different beer styles?
IBU targets by style: American light lager 8-12, Hefeweizen 10-15, English pale ale 25-40, American IPA 40-70, West Coast IPA 60-80, Imperial IPA 80-120, English porter 20-30, American stout 25-40. These are guidelines — the perceived bitterness also depends on residual sweetness (final gravity) and malt character, not just raw IBU.
What is a typical homebrew efficiency and why does it matter?
Most homebrewers achieve 65-75% brewhouse efficiency. This means if your grain bill theoretically contains 1,000 gravity points, you extract 650-750 of them. Higher-end setups with better milling and lautering can reach 80-85%. Efficiency matters because it determines how much grain you need to hit a target original gravity. If your efficiency drops, you need more grain or a larger grain bill to compensate.
Why does water chemistry matter for homebrewing?
Water mineral profile directly affects hop perception and malt character. High sulfate (200+ ppm) makes hops taste crisper, drier, and more assertive — ideal for IPAs. High chloride (100+ ppm) softens bitterness and emphasizes malt sweetness — ideal for English milds and lagers. Bicarbonate above 150 ppm raises mash pH, reducing efficiency and creating harsh bitterness. Matching your water to the style prevents technically correct but flat-tasting beer.
How do I calculate strike water temperature for all-grain brewing?
The formula accounts for grain temperature, grain weight, water volume, and equipment thermal mass. For a simple estimate: Strike Temp = (0.2/R) × (T2 - T1) + T2, where R = water/grain ratio in qt/lb, T1 = grain temperature, T2 = target mash temperature. At 1.25 qt/lb ratio with grain at 68°F targeting 152°F mash, strike water needs to be about 163-165°F. The Strike Water Calculator handles this exactly.