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Alcohol Dilution Reduction Table

Engineering Physics

Use this table to determine the correct dilution of Alcohol to lower strengths.

Desired strength
Alcohol Dilution Reduction Table [Dilution of Alcohol to Lower Strengths]
Strengths to be Reduced (% v/v)
% v/v
95%
90%
85%
80%
75%
70%
65%
60%
55%
50%
45%
40%
35%
30%
25%
20%
15%
Volume Units of Pure Water to Add to Each 100 Volume Units of Alcohol
90%
6.41
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
85%
13.33
6.58
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
80%
20.9
13.8
6.83
-
-
-
-
-
-
-
-
-
-
-
-
-
-
75%
29.5
21.9
14.5
7.2
-
-
-
-
-
-
-
-
-
-
-
-
-
70%
39.1
31.0
23.1
15.3
7.64
-
-
-
-
-
-
-
-
-
-
-
-
65%
50.2
41.5
33.0
24.6
16.4
8.15
-
-
-
-
-
-
-
-
-
-
-
60%
63.0
53.6
44.2
35.4
26.5
17.6
8.76
-
-
-
-
-
-
-
-
-
-
55%
78.0
67.8
57.9
48.0
38.3
28.6
19.0
9.5
-
-
-
-
-
-
-
-
-
50%
95.9
84.8
73.9
63.1
52.4
41.7
31.3
20.5
10.4
-
-
-
-
-
-
-
-
45%
118
105
93.3
81.3
69.5
57.8
46.0
34.5
22.9
11.4
-
-
-
-
-
-
-
40%
144
131
117
104
90.8
77.6
64.5
51.4
38.5
25.6
12.7
-
-
-
-
-
-
35%
179
163
148
133
118
103
88.0
73.0
58.3
43.6
29.0
14.4
-
-
-
-
-
30%
224
206
189
171
154
136
119
102
85.0
67.5
50.5
33.5
16.7
-
-
-
-
25%
287
266
245
224
204
183
162
142
121
101
80.4
60.2
40.0
20.0
-
-
-
20%
382
356
330
304
278
253
227
201
176
150.6
125.2
100
75.0
49.9
24.9
-
-
15%
540
505
471
437
403
369
335
301
267
234
200
166.4
133
96.7
66.4
33.2
-
10%
855.6
804
753
703
652.2
602
551
500.6
450.2
400
350
300
249.4
199.4
150
100
50
Alcohol water mixtures are non-volume additive mixtures. This table may be used to determine the volume of water needed to reduce known volume strengths of alcohol solutions (such as distilled spirits or sensory evaluation or the cutting of spirits to desired final strengths) to desired volume/volume strengths.
Example calculation of DATA: [Requires "RESPECTIVE VOLUMES OF ALCOHOL AND WATER AND THE SPECIFIC GRAVITY IN BOTH AIR AND VACUUM OF SPIRITUOUS LIQUOR" - or its equivalent - from the US Gov. Gauging Manual: “Respective Volumes of Alcohol and Water”. In reducing 95% (vol.) to 85% (vol) first convert to Proof (US), i.e. x Vol. by 2. Then see US Gauging Manual - Table 6. 190 Proof is 95% (vol.) Ethanol and 6.18% (vol.) H20. 170 Proof is 85% (vol.) Ethanol and 17.46% (vol.) H20. Ratio: 95/85 = 1.1176471*--then-- 17.46% (vol. water in 85% vol/vol alcohol water mixture) x 1.1176471* = 19.514118* Next: 19.514118* - 6.18 = 13.33; Dilution is now 100 Units [e.g., gallons, mL. etc.] of the initial alcohol solution to 13.33 Units of water. *[Significant figures not accounted for.] Prepared by Gary Spedding