The alcohol % vol equals the number of liters of absolut etilic alcohol, contained in 1
It is determined by simple distillation, of the neutralized liquid, and measured the density of the distilled liquid through areometry.
1. Measure 250 mL of wine with the volumetric flask. Introduce the measured wine in the 1000 mL spherical flask and rinse with 10 mL of distilled water the 250 mL flask and throw them in the distillation flask. Repeat this step 2-3 more times.
2. Neutralize the wine sample to analyse with 10 mL of Calcium Oxide solution. Prepare the solution with very precaution with 120 gr. of Calcium Oxide per liter of distilled water.
3. Set the distillation flask over the closed retort ring with the iron gauze. Joint it with the vigreaux column and this one with the coil condenser through the double bent. Use the same 250 mL volumetric flask as collector of the distillated sample.
4. Set the Bunsen burner under the spherical flask and light it on. Verify the distillation taking care in cooling water being always cold.
5. Proceed to the distillation till collecting nearly to the mark of 250 mL (about 2-3 cm below). Light the Bunsen burner of and fill the volumetric flask with distilled water till the mark to obtain the same volume as before.
6. Pour the distilled liquid to the 250 mL measuring cylinder, cover it and stirr it.
7. Measure the temperature, then dive the 10-20 % alcohometer into the liquid and calibrate it to 20ºC, procuring it to be clean and dry, and let it float.
8. When the alcohometer is floating in rest without touching the glass of the measuring cylinder and all air bubbles have been disappeared, read below the meniscus that forms the liquid.
In case of distilling wines that has not already finish fermentations or haven't been filtered correctly or that contain carbon dioxide, liable to do foam when boiling them, pour to the wine, before distilling it, some drops of antifoaming silicone.
Consult the temperature correction tables in the section Tables à Alcohometric Corrections