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Calculate beer IBU from hop additions, alpha acid percentage, boil time, and batch volume. Estimate bitterness for homebrew recipe design.
Calculate mash and sparge water volumes from grain bill weight, mash thickness, and target pre-boil volume for all-grain homebrewing.
Calculate priming sugar amount for bottle conditioning from batch volume and target volumes of CO2. Carbonate beer with corn sugar, DME, or honey.
Standard ale: 0.75 million cells/mL/°Plato. Lager: 1.5 million. High-gravity (>1.060): 1.0+ million. Double for repitching from slurry with unknown viability.
Cells needed = Volume (mL) × °Plato × Pitch rateA 1–2 liter starter with 1.040 OG DME wort and intermittent shaking yields 2–3× cell count increase from a fresh smack pack or vial (~100 billion starting cells).
Final cells ≈ Starting cells × Growth factor (2–3×)1.040 OG starter wort: 100 g DME per liter of water. Use 1.030–1.040 OG — higher gravity stresses yeast and reduces growth.
DME (g) = Starter volume (L) × 100Updated: July 2026
19 L × 12.4°P × 0.75M = ~177 billion cells needed. One fresh yeast pack (~100B) needs a 1.5 L starter for ~200B cells after growth.
Lager pitch rate 1.5M: ~354 billion cells needed. Use 2-step starter — 1 L then 2 L — or two packs with 2 L single starter.
19 L × 21.6°P × 1.0M = ~410 billion cells. Require 3–4 L starter or multiple packs. Oxygenate thoroughly at pitch.
High-OG starter wort stresses yeast and produces fewer new cells. Keep starter at 1.030–1.040 for maximum growth rate and healthy pitch.
Chill starter to flocculate yeast, decant spent starter beer, pitch yeast slurry only. Two liters of starter beer dilutes OG and adds oxidized starter flavors.
Healthy fermentation requires adequate yeast cell count proportional to wort gravity and volume. Liquid yeast packages often contain fewer cells than high-gravity or large batches demand. This calculator sizes yeast starters with DME to reach target pitch rates.