MY ACCOUNT
CONTACT
BLOG
A PROJECT ?
In craft and industrial brewing, measuring the wort gravity is the first performance indicator. It allows you to evaluate mash efficiency, calculate dissolved extract, and control fermentation.
However, depending on the origin of your equipment, your recipe‑formulation software, or your suppliers’ standards, you will encounter three different measurement units: Specific Gravity (SG), Degrees Brix (°Bx), and Degrees Plato (°P).
Discover our complete correspondence guide and our conversion tools for your brewery laboratory equipment.
1. Understanding the 3 density measurement units
- Specific Gravity (SG):
Widely used in the English‑speaking world and in homebrewing, it compares the mass of a volume of wort to the same volume of pure water at 20°C. Pure water has an SG of 1.000. A standard wort generally ranges between 1.040 and 1.080. - Degrees Brix (°Bx):
This is the international unit used by optical and digital refractometers. One degree Brix corresponds to 1 gram of pure sucrose per 100 grams of aqueous solution at 20°C. It is the fastest unit to measure during brewing. - Degrees Plato (°P):
This is the reference unit in professional European and industrial brewing. By relating the wort’s density to its actual percentage of dissolved extract, Plato is more precise than Brix because it accounts for the complexity of malt wort sugars (maltose, maltotriose, dextrins) rather than sucrose alone.
2. Direct mathematical conversion formulas
To quickly convert values on your brewing sheets without a table in front of you, use these simplified formulas:
Specific Gravity (SG) = 1 + (Degrees Plato × 0.004)
Example: For a wort at 12 °P → 1 + (12 × 0.004) = 1.048 SG
Degrees Plato (°P) = (SG − 1) / 0.004 (or the last three digits of SG divided by 4)
Example: For a gravity of 1.060 → 60 / 4 = 15 °P
Degrees Plato (°P) = Degrees Brix (°Bx) / 1.04
Note: Brix values are always slightly higher than Plato values for malt wort.
3. Master conversion table SG / Brix / Plato
This table summarizes the correspondences for unfermented wort measured at 20°C:
| Degrees Plato (°P) | Degrees Brix (°Bx) | Specific Gravity (SG) | Beer Category / Usage |
|---|---|---|---|
| 6.0 °P | 6.2 °Bx | 1.024 | Very light beer / Session Table Beer |
| 8.0 °P | 8.3 °Bx | 1.032 | Light beer, Berliner Weisse |
| 10.0 °P | 10.4 °Bx | 1.040 | Classic Pilsner, Session IPA |
| 12.0 °P | 12.5 °Bx | 1.048 | Standard Pale Ale / Blonde / Amber |
| 14.0 °P | 14.6 °Bx | 1.057 | IPA, Bière de Garde, Saison |
| 16.0 °P | 16.6 °Bx | 1.065 | Double IPA, Robust Porter |
| 18.0 °P | 18.7 °Bx | 1.074 | Strong Belgian Ale, Imperial Stout |
| 20.0 °P | 20.8 °Bx | 1.083 | Belgian Tripel, Barley Wine |
| 22.0 °P | 22.9 °Bx | 1.092 | Imperial Pastry Stout, Quadrupel |
| 24.0 °P | 25.0 °Bx | 1.102 | Very dense wort / Malt liquor |
4. Common pitfalls to avoid during laboratory measurements
- Reference temperature (20°C): Laboratory hydrometers and refractometers are calibrated for measurements at 20°C. If you measure hot wort straight from the boil (80°C), the wort is expanded and your reading will be falsely low. Let your sample cool or apply a thermal correction table.
- Optical refractometer vs digital densitometer: A manual optical refractometer provides an excellent approximation in the brewhouse, but for customs declarations or packaging control, a digital oscillating‑tube densitometer (e.g., Anton Paar) or a precision pycnometer is recommended.
Rolling Beers Technical Team’s Advice
Which unit should you choose in a professional lab?
For daily work, we recommend adopting Degrees Plato (°P) as the standard unit on your production brewing sheets. It is the most representative of dissolved extract and the most universal in professional brewing. Keep the Brix refractometer for ultra‑fast checks at the mash paddle during lautering!