Homebrew Yeast Calculator: Pitching Rate & Starter Size

🍺 Homebrew Yeast Calculator

Calculate pitching rate, cell count, starter size, and viability for your homebrew

Quick Presets
🧮 Calculator
Cells Needed
--
billion cells
Cells Available
--
billion cells
Pitch Status
--
--
Yeast Viability
--
% of original cells alive
📊 Pitching Rate Quick Reference
0.75M
Ale cells/mL/°P
1.0M
High-Grav Ale cells/mL/°P
1.5M
Lager cells/mL/°P
2.0M
High-Grav Lager cells/mL/°P
🧪 Pitching Rates by Beer Style & OG
Beer StyleOG RangeRate (M/mL/°P)5G @ 1.050 Needs
Standard Ale1.030 – 1.0750.75~175B cells
High-Gravity Ale> 1.0751.00~233B cells
Wheat Beer1.040 – 1.0600.75~175B cells
Standard Lager1.030 – 1.0601.50~350B cells
High-Gravity Lager> 1.0602.00~466B cells
🧬 Yeast Viability Over Time
Months OldLiquid Yeast ViabilityCells in 1 Pack (~100B)Action Needed
0 – 1 month~97%~97BLikely no starter
2 months~79%~79BConsider starter for lagers
3 months~61%~61BStarter recommended
4 months~43%~43BStarter required
5 months~26%~26BLarge starter required
6 months~9%~9BConsider fresh yeast
📏 Starter Size Cell Growth Estimates
Starter VolumeCells Added (No Stir)Cells Added (Stir Plate)Total from 100B Pack
0.5L+25B+50B125–150B
1.0L+50B+100B150–200B
1.5L+75B+150B175–250B
2.0L+100B+200B200–300B
3.0L+150B+300B250–400B
4.0L+200B+400B300–500B
🍻 Liquid vs. Dry Yeast Comparison
100B
Liquid Pack (fresh)
200B
Dry Packet (11g)
~4%
Dry Viability Loss/Mo
~18%
Liquid Viability Loss/Mo
📝 Gravity to Plato Conversion Reference
Original Gravity (OG)Degrees Plato (°P)Style ExampleAle Cells Needed (5G)
1.0307.6°PSession Ale / Light Lager~107B
1.04010.0°PWheat Beer / Kolsch~140B
1.05012.4°PPale Ale / Amber Ale~174B
1.06014.7°PIPA / Porter~206B
1.07518.2°PDouble IPA / Strong Ale~255B
1.09021.6°PImperial Stout / Barleywine~605B (high-grav)
1.10023.8°PRussian Imperial Stout~666B (high-grav)
💡 Tip: Underpitching is one of the most common homebrewing mistakes. Too few yeast cells leads to a long lag time, stressed fermentation, and off-flavors like acetaldehyde, fusel alcohols, and excessive esters. Always calculate your pitch rate before brew day.
💡 Tip: For lagers, always make a starter. Lager yeast requires up to twice as many cells as ale yeast due to cold fermentation temperatures. A 2-liter starter on a stir plate for 24 hours before pitching will give you significantly better results.
💡 Tip: Dry yeast generally does not need a starter — it already contains roughly 200 billion cells per 11g packet and retains high viability for 2+ years when stored properly. Simply rehydrate in 95°F (35°C) water for 15 minutes before pitching.

Brewing yeast is the most important of the four main ingredients: hops, malt, water and yeast. Without it you only get bitter grain water that never fermented. Grain, water and hops all matter, but yeast genuinely decides if the beer succeeds or fails

Homebrewers can use many kinds of yeast strains. Some of them occasionally simply are not available. For the quality of the finished beer it matters to choose the right yeast strain.

Yeast Is the Most Important Ingredient in Beer

Homebrewers find yeast in two forms: liquid and dry. Both work well and give good beer if you care for them and use them correctly. More strains are liquid than dry, but dry yeast is a good and viable altrenative for liquid yeast during homebrewing.

More than 50 dry yeast strains can compete with liquid options.

Ale and lager yeasts are the two most common kinds. One packet of dry yeast suffices for most ale beers of middle density. Liquid packets have different amounts and commonly require two for some ale.

Lager beers require double because they ferment cold. The official advice is use two packets of dry yeast for lager because of the low temperature. One packet weigths around 11 grams.

US-05 is dry yeast that each homebrewer should have. It works well for IPAs when you want simple fermentation character. Wyeast 1056 and WLP001 are liquid matches.

All of them give alike taste, but US-05 attenuates more strongly on average. S-04 works also well, but the esters and taste it creates do not please everyone. It distinctly separates itself and forms firm yeast cakes after fermentation, which is a bonus.

The best way to ensure active and ready yeast is to prepare a yeast starter. Every yeast strain, including lager, you incubate at 70°F for fast growth. Starter cultures can seem less active than a full batch.

The most reliable sign of activity is the density reading. Starters look commonly milky or cloudy during fermentation and clear with white sediment ultimately.

Yeast nutrient is made up of a complex mix of useful things for yeast. One of them is FAN, that yeast uses for good activity. You say that fruits like raisins give it well, but that is not genuinely true.

More yeast helps to close more quickly and shorten lag time. One of the main secrets for good beer is a healthy, unstressed yeastpopulation.

Homebrew Yeast Calculator: Pitching Rate & Starter Size

Leave a Comment