Glucose + Fructose
Glucose + Fructose are measured using the FOSS FTIR Winescan or the Randox Daytona enzymatic analyser. This may also be measured in combination with organic acids by HPLC.
Sucrose
The Rebelein method provides a method of determining the reducing sugars present in wine and grape juice samples. This method involves reacting the reducing sugars present in these sample with excess alkaline cupric (Cu++) tartrate, from which the concentration of reducing sugars is determined from the amount of Cu++ remaining after reaction. The Cu++ remaining can be determined by reducing the Cu++ with iodine (2Cu++ + 2I– → 2Cu+ + I2) and estimating the remaining iodine with standard thiosulphate solution (I2 + 2S2O32- → 2I– + S4O62-).
Brix/Baumé
Brix is measured using a digital refractometer and can easily be converted to baumé by dividing the brix result by 1.8.
Specific gravity
A FOSS FTIR Winescan density meter may be used to measure specific gravity. Specific gravity is a requirement of some export certificates.
| Prices per analysis | |||
|---|---|---|---|
| Analysis | Per Sample (excluding GST) | Volume required | Target response time |
| Glucose + Fructose by Winescan | $10 | 50 mL | 24 hrs |
| Specific Gravity by Winescan | $10 | ||
| Brix / Baumé | $10 | 10 mL or 200 berries | 24 hrs |
| Sucrose by Rebelein | $35 | 25 mL | 24 hrs |
| Reducing Sugar by Rebelein | $25 | ||
| Glucose + Fructose by Daytona | $30 | 10 mL | 24 hrs |
| Specific gravity by density meter | $20 | 25 mL | 24 hrs |
For more information, please contact AWRI Commercial Services on (08) 8313 6600 or e-mail commercialservices@awri.com.au