Wine Analysis Home
Alcohol Determination by Distillation Procedure -
Introduction
Common Errors
1. - Measure out exactly 250ml of clear wine in a 250 ml volumetric flask - (see method)
2. - Empty the wine out of the volumetric flask into the distillation flask and employ a couple of distilled water rinses to remove wine residues from the volumetric flask into the distillation flask, bringing the total distillation flask contents to approximately 450 ml.
3. - Add some boiling chips (pumice powder) to the distillation flask to prevent bumping when boiling the contents.
Caution: do not add the boiling chips once heating has commenced.
4. - Set up apparatus as per diagram using the same volumetric flask and making sure that all joints are securely fitted (see safety note)
5. - Apply heat to the bottom of the boiling flask and collect approximately 220 ml of distillate.
If the heat from the burner is to local or intense, position a tripod and heat diffuser (gauze), to disperse the applied heat, between the heat source and boiling flask.
6 - Caution, before removing the heat from the boiling flask, loosen and lower the adapter receiver from the condenser.
7. - Lift the extended receiver adaptor out and above the surface of the distillate and rinse any residues with distilled water from a squeeze bottle into the volumetric flask.
8. - Top up the contents of the volumetric flask with distilled water close to 250 ml graduation mark, bring to 20oC in a hot water bath, then top up to the 250ml graduation mark. Stopper and mix (see method).
9. - Use a small amount of the collected, diluted distillate to rinse a clean 250ml measuring cylinder.
Then pour all of the distillate into the cylinder.
10. - Using an alcohol hydrometer, measure the alcohol of the solution and record your reading.
11. - Using a thermometer measure the temperature of the solution and record your reading.
12. - Determine the true concentration of alcohol from the alcohol-temperature correction table and record the result.
CommonErrors