📏 Batch Scaling Calculator
Scale recipes up or down while maintaining ratios
Easily scale your brewing recipes to different batch sizes. This calculator maintains all ingredient ratios, hop additions, and timing while adjusting quantities to match your target volume.
Recipe Ingredients
📚 Understanding Recipe Scaling
Recipe scaling is straightforward for most ingredients - simply multiply by the scaling factor. However, some adjustments may be needed for certain components to maintain the same flavor profile and brewing characteristics.
Scaling Formula:
Scaling Factor = Target Batch Size ÷ Original Batch Size
New Amount = Original Amount × Scaling Factor
What Scales Linearly:
- Base malts: Scale directly with batch size
- Specialty malts: Scale directly for consistent flavor
- Bittering hops: Scale directly to maintain IBUs
- Flavor/aroma hops: Scale directly (generally)
- Water volumes: Scale all water additions
- Yeast (cell count): Scale based on volume × gravity
What May Need Adjustment:
- Whirlpool/hop stand hops may need reduction when scaling up
- Larger volumes retain heat longer = more extraction
- Consider 10-20% reduction for large scale-ups
- Mineral additions (gypsum, calcium chloride) scale linearly
- Acid additions may not scale exactly - test pH
- Water-to-grist ratio stays the same
- Boil time stays the same regardless of batch size
- Boil-off rate increases with larger surface area
- May need to adjust pre-boil volume
- Check mash tun capacity before scaling up
- Fermenters need 20-25% headspace
- Kettle size limits maximum batch
- Cooling time increases with larger batches
Common Scaling Scenarios:
- 5 gal → 10 gal (2x): Most common scale-up, double all ingredients
- 5 gal → 15 gal (3x): Commercial pilot batch scale-up
- 10 gal → 5 gal (0.5x): Half batch for testing
- 5 gal → 2.5 gal (0.5x): Small test batch or split batch
- 15 bbl → 5 bbl (0.33x): Commercial to pilot system
Tips for Scaling Up (>2x):
- Recalculate boil-off rate for your larger kettle
- Ensure adequate cooling capacity (may need longer cooling time)
- Check mash tun can handle grain bill + water
- Consider splitting yeast starter into multiple batches
- Late hop additions may need slight reduction
- Longer mash/lauter times may be needed
- Monitor temperatures more carefully (larger thermal mass)
Tips for Scaling Down (<0.5x):
- Small batches lose heat faster during mash
- May need to insulate mash tun better
- Boil-off percentage may be higher (more surface area ratio)
- Easier to hit target temperatures
- Great for recipe testing before committing to full batch
- Can use smaller/less yeast (even half a packet)
Yeast Scaling Considerations:
- Calculate proper pitch rate using yeast calculator
- For 2x scale: Generally 2 packets dry yeast or make larger starter
- For 3x+ scale: Consider using yeast harvested from previous batch
- Pitch rate = millions of cells per mL per °Plato (doesn't change)
- Absolute cell count scales with volume
Water Chemistry Scaling:
Most water additions scale linearly:
- Gypsum (CaSO₄): Scale directly
- Calcium Chloride (CaCl₂): Scale directly
- Epsom Salt (MgSO₄): Scale directly
- Baking Soda (NaHCO₃): Scale directly
- Lactic/Phosphoric Acid: Scale, but verify pH
Efficiency Considerations:
- Brewhouse efficiency may vary slightly with batch size
- Larger grain beds can improve efficiency slightly
- Small batches (<2 gal) may have lower efficiency
- Track your efficiency at different scales
- Adjust grain bill if efficiency differs significantly
Practical Scaling Limits:
- Minimum practical size: ~1 gallon (measurement accuracy issues below)
- Maximum scale factor: Limited by equipment capacity
- Recommended range: 0.5x to 3x without major adjustments
- Beyond 5x: Requires equipment-specific adjustments
Example Scaling:
- 10 lb Pale Malt
- 1 lb Crystal 60L
- 1 oz Cascade (60 min)
- 1 oz Cascade (5 min)
- US-05 Yeast (1 packet)
- 20 lb Pale Malt
- 2 lb Crystal 60L
- 2 oz Cascade (60 min)
- 1.5-2 oz Cascade (5 min) ← slightly reduced
- US-05 Yeast (2 packets)
❓ Frequently Asked Questions
How do I scale a homebrew recipe to a different batch size?
To scale a recipe, divide your target batch size by the original batch size to get the scaling factor. Then multiply all ingredient amounts by this factor. For example, to scale a 5-gallon recipe to 10 gallons, your scaling factor is 2.0x, so you'd double all ingredients.
Do all ingredients scale linearly?
Most ingredients scale linearly - base malts, specialty grains, bittering hops, and water additions all scale directly with the scaling factor. However, late hop additions may need slight reduction when scaling up (10-20% less) because larger volumes retain heat longer and extract more hop character.
How do I scale yeast when changing batch size?
Yeast pitch rate (cells per mL per degree Plato) stays constant, but the absolute cell count scales with volume. For a 2x scale-up, use 2 packets of dry yeast or make a proportionally larger starter. Calculate proper pitch rates using a yeast calculator for best results.
What equipment limitations should I consider when scaling up?
Check your mash tun capacity (grain bill plus water), fermenter size (needs 20-25% headspace), kettle size, and cooling capacity. Larger batches take longer to cool and may require extended mash/lauter times. Equipment is often the limiting factor in how much you can scale.
Can I scale recipes down to smaller test batches?
Yes! Scaling down (0.5x or smaller) works well for recipe testing. Keep in mind that small batches lose heat faster during mashing, may have higher boil-off percentages due to surface area, and can use less yeast (even half a packet for small batches).
Does brewhouse efficiency change with batch size?
Efficiency can vary slightly with batch size. Larger grain beds may improve efficiency slightly, while very small batches (<2 gallons) can have lower efficiency due to grain bed depth and water absorption ratios. Track your efficiency at different scales and adjust grain bills accordingly.