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DISTILLATION OF WINE
By Walter Scharf and Charles Malerich
Natural Sciences/Chemistry
Baruch College
New York, NY 10010
Introduction
One of the oldest chemical reactions utilized by man is fermentation- - the conversation
of sugar in fruit juice into alcohol and carbon dioxide by the action of yeast. The fermentation of
grape sugar can be depicted by the equation,
C6H1206 + Zymase à 2C2H5OH + 2CO2 + Zymase
(1a)
or in words
Glucose + Zymase from yeast à grain alcohol + carbon dioxide
(1b).
The reaction will proceed until the alcohol content of the fermentation mixture rises to a toxic
level and poisons the yeast. At this point a solution is present which contains sugar, alcohol, and
water is commonly called wine. (If the carbon dioxide is not allowed to escape, the solution is
called champagne.) By separating the alcohol from the wine, other alcoholic beverages can be
prepared which contain a higher alcohol content than wine. This separation is affected by the
process known as distillation which is the subject of the next paragraph and this experiment. To
complete the making of a quality distilled spirit or beverage, the alcohol obtained from
distillation will be aged in a charred wooden barrel. This process removes, by absorption on the
wood surface, some bad tasting impurities which are not removed by the distillation process.
“Bootlegged” liquor is not aged, and hence retains the unwanted impurities.
In separating alcohol from wine, a chemist affects the separation of a liquid from a
solution, and, as mentioned previously, this separation can be accomplished by distillation.
Distillation is based on the fact that the matter can exist in three phases - - solid, liquid and gas.
As the temperature of a pure substance is increased, it passes through these phases, making a
transition at a specific temperature from solid to liquid (melting point--mp) and then at a higher
temperature from liquid to gas (boiling point--bp). Distillation involves evaporating a liquid into
a gas phase, then condensing the gas back into a liquid and collecting the liquid in a clean
receiver. Substances that have a higher boiling point than the desired material will not distill at
the working temperature, and remain behind in the flask. Applied to the preparation of alcoholic
beverages, alcohol has a lower boiling point than water (and sugar) and thus distillation can
separate the alcohol from the wine. Some water also evaporates, and the separation is not
complete, hence liquors are not pure alcohol and bottles of alcoholic beverages are labeled with
the alcohol content. For fermented beverages, like wine and beer, the alcohol content is
expressed in percent by volume, while for distilled liquors the alcohol content is usually given in
terms of a “proof” rating. Proof is equal to twice the percent by volume of alcohol. Distillation
has many other applications. One significant example is the refining of gasoline and other
products from crude petroleum.
Procedure
In this procedure, wine will be distilled and the alcoholic content of the distillate determined.
The distillate from wine is called brandy (short for Brandywine).
Distillation
1. Obtain a thermometer distilling flask and condenser from the front of the room.
2. Assemble the distilling apparatus as shown in the figure (See next page).
3. Remove the thermometer and place a boiling chip and about 75ml of wine using a long-stem
funnel into the distilling flask.
4. Turn on the cooling water and have the instructor check your setup, then apply the heat to the
wine. After boiling begins, reduce the heat so the wine boils at a moderate rate.
5. Watch the temperature closely while distilling and collect the distillate coming from the
condenser while the temperature is in the range 80-850C. The temperature should remain nearly
constant in this range.
6. When the temperature rises above 85 oC, begins to increase, quickly change collecting flasks
then continues distilling until the temperature is between 98 and 100 oC.
7. Record the temperature range over which you collected the alcohol enriched distillate.
Determination of alcohol content of the distilled spirit (brandy)
8. Determine the density of the brandies collected by weighing a known volume of each. Brandy
(see density experiment).
9. From the table of density versus percent alcohol and the result of step 8, determine the alcohol
content of the distilled spirit. Record your result.
Proof test
10. Using three watch glasses, pour a small volume of the two brandies and the undistilled wine
respectively into a watch glass. Record the contents of each watch glass and then try lighting the
liquid with a wooden splint. Record whether the liquid in each watch glass burns or does not
burn. Be careful, alcohol burns with a very faint blue flame. Extinguish any burning liquids
with cold water before handling.
Density vs. Percent Alcohol of Aqueous Ethanol Solutions at 200C
D204
% alcohol by volume
D204
% alcohol by volume
0.9973
0.50
0.9504
32.00
0.9963
1.00
0.9468
34.00
0.9954
1.50
0.9431
36.00
0.9945
2.00
0.9392
38.00
0.9936
2.50
0.9352
40.00
0.9927
3.00
0.9311
42.00
0.9918
3.50
0.9269
44.00
0.9910
4.00
0.9227
46.00
0.9902
4.50
0.9183
48.00
0.9893
5.00
0.9139
50.00
0.9885
5.50
0.9095
52.00
0.9878
6.00
0.9049
54.00
0.9870
6.50
0.9004
56.00
0.9862
7.00
0.8958
58.00
0.9855
7.50
0.8911
60.00
0.9847
8.00
0.8865
62.00
0.9840
8.50
0.8818
64.00
0.9833
9.00
0.8771
66.00
0.9826
9.50
0.8724
68.00
0.9819
10.00
0.8676
70.00
0.9805
11.00
0.8629
72.00
0.9792
12.00
0.8581
74.00
0.9778
13.00
0.8533
76.00
0.9765
14.00
0.8485
78.00
0.9752
15.00
0.8436
80.00
0.9739
16.00
0.8387
82.00
0.9726
17.00
0.8335
84.00
0.9713
18.00
0.8284
86.00
0.9700
19.00
0.8232
88.00
0.9687
20.00
0.8180
90.00
0.9660
22.00
0.8125
92.00
0.9632
24.00
0.8070
94.00
0.9602
26.00
0.8013
96.00
0.9571
28.00
0.7954
98.00
0.9539
30.00
0.7893
100.00
Report sheet for distillation of wine
Name_____________________Lab section_____________Date_____________
Type of wine used______________________
% Alcohol in wine (see label on bottle)_____________%
Density of distilled spirit (Brandy)
a) Via hydrometer reading:___________%
b) Via measurement and calculation
Weight of graduated cylinder + brandy: ___________g
Weight of graduate cylinder:
___________g
Weight of Brandy:
___________g
Volume of brandy in cylinder:
___________ml
Density of brandy
___________g
Ml
= ___________g/ml
% Alcohol in brandy (from table):
____________%
Proof rating of Brandy:
_____________proof
Proof test
Identity of sample __________________
Burns or does not burn
Identity of sample __________________
Burns or does not burn
Identity of sample __________________
Burns or does not burn
Questions
1. Discuss the phenomenon of rain, in terms of vaporization and condensation. Is rain-water
distilled water?
2. Port and sherry are called “fortified wines”, because alcohol is added to a fermented wine to
prevent it from turning to vinegar when exposed to air. Beginning with squeezed grape-juicewhich contains sugar, water, and yeast- design a procedure for making a fortified wine.
3. What happens to the proof-rating of the brandy, as the distillation process continues? Why?
4. Commercial brandy is brown in color, while your “raw” brandy is colorless. Why the
difference? Is brandy simply a water-alcohol mixture?
5. Using four well separated points from the table of density and percent alcohol by volume,
make a density vs. percent alcohol by volume graph. Is the relationship between density and
percent alcohol by volume a linear one?