Dry Yeast Pitch Rate Calculator
Specific Gravity (e.g., 1.050)
0.35 – Manufacturer Minimum
0.50 – Standard Ale
0.75 – Pro Ale / High Gravity
1.00 – Hybrid / High Gravity Ale
1.50 – Lager
2.00 – High Gravity Lager
Conservative estimate is 10B/g. Fermentis/Lallemand often guarantee >6B/g but contain ~10-20B/g.
Gravity in Plato:
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Total Cells Required:
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Dry Yeast Needed:
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Packets Needed:
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Understanding Dry Yeast Pitch Rates
Pitch rate refers to the amount of yeast cells added to the wort to ensure a healthy fermentation. Unlike liquid yeast, dry yeast comes packed with nutrient reserves (glycogen and trehalose) and sterols, making it robust and generally requiring no starter.
Why calculate pitch rate? Under-pitching can lead to stressed yeast, off-flavors (esters and phenols), stuck fermentations, and higher infection risks due to long lag times. Over-pitching, while less common with homebrewers due to cost, can result in "yeast bite" or lack of characteristic esters in certain styles.
How It Works: The Math
This calculator determines the total biomass needed based on your wort volume and sugar density (Original Gravity). The formula typically used relies on degrees Plato and a specific cell multiplier.
- Degrees Plato (°P): An approximate conversion is
(OG - 1) * 250. For example, 1.050 SG is roughly 12.5°P. - Target Cells: The standard formula is
Volume (mL) * Plato * Pitch Rate. - Pitch Rates:
- 0.35 – 0.5 M/mL/°P: Often sufficient for dry yeast in standard gravity ales due to high viability.
- 0.75 M/mL/°P: The professional standard for ales to ensure consistency.
- 1.5 M/mL/°P: The standard for lagers, which ferment colder and slower.
Dry Yeast Cell Density
There is significant debate regarding the number of cells in a gram of dry yeast. Manufacturers like Fermentis and Lallemand typically guarantee a minimum of 5-6 billion cells per gram. However, microscopic counts often reveal actual densities of 10 to 20 billion cells per gram. This calculator defaults to a conservative estimate of 10 billion cells/gram to ensure you pitch enough yeast without excessive waste.
Tips for Success
For high gravity beers (OG > 1.060), consider increasing your pitch rate to 1.0 or 1.25. For lagers, always double the pitch rate compared to ales. While rehydration of dry yeast was once strictly recommended, many modern dry yeast strains can be sprinkled directly onto the wort with excellent results.