Question

how can you test for the alcohol concentration of wine?

Answer 1

idk why u want to know this lol but here it is:

1.Measure the SG of the wine you wish to test.We will call this figure SG-1.

2.Measure exactly one pint of the wine (500ml).We will call this the sample.

3.In a enamelled or glass pan,boil the sample down to about half it's original volume.This drives off some of the water,but all of the alcohol,because alcohol boils at a lower temperature than water.The sample now consists of water,residual sugar,colouring matter,acids and proteins-that is,all the non-alcoholic constituents of the wine.

4.With distilled water or rain water,make the boiled-down sample up to exactly a pint again.Tap water is not recommended because,in some areas,it has a considerable dissolved mineral content which could affect your results.

5.Cool the sample down to 60o-F, or what ever temperature your hydrometer is calibrated for.

6.Read the SG of the sample,we will call this reading SG-2.You will find it higher than SG-1 because you have removed the alcohol and replaced it with water.

7.Subtract SG-1 from SG-2. The difference is called the Spirit Indication.

8.Read the alcohol strength from the following table.

Spirit Indication---- Alcohol Strength,% by volume
1.5 ----------------------- 1,0
2-------------------------- <email> -------------------------- 3.4
6-------------------------- 4.1
7-------------------------- 4.9
8-------------------------- 5.6
9-------------------------- 6.4
10------------------------- 7.2
11------------------------- 8.0
12------------------------- 8.8
13------------------------- 9.7
14------------------------- 10.5
15------------------------- 11.4
16------------------------- 12.3
17------------------------- 13.2
18------------------------- 14.1
19------------------------- 15.1
20------------------------- 16.0
21------------------------- 17.0
22------------------------- 18.0
23------------------------- 19.0
24------------------------- 20.0
25------------------------- 21.0
26------------------------- 22.0

As an example:
SG-1 (SG of oraginal wine) = 0.995
SG-2 (SG of sample at stage 6) =1.011
Spirit Indication= 1.011 - 0.995 = 16
Alcohol strength= 12.3 % by volume.

Buy a short range hydrometer, reading from 0.990 to 1.020. This should let you read SG to half a degree.You can then work out a spirit indication to half a unit and by interpolation on the table reach a closer value for alcohol strength.

Answer 2

Very detailed :3 however, is there a method that I could use that would not require heating? I am currently doing a school experiment that is going to investigate the difference between wine samples from different temperatures.

Answer 3

hmmm idk

Answer 4

You have access to any chemicals you need?

Answer 5

Yes we should... ;)

Answer 6

You could use heptaoxidodichromate as an oxidizing agent... When ethanol react with heptaoxidodichromate to create chrom(III) ions. The smart part:
Heptaoxidodichromate looks red orange, while chrom(III) ions are green... the color change may then indicate the amount of alcohol.

Answer 7

Use a spectrophotometer to get quantitative results.

Answer 8

Chromic acid might be better to use as name.

Answer 9

I will look into it thanks :P

Answer 10

Do what Frostbite suggested, although there may be other reagents that react with ethanol in a similar manner. You will need to have a standard curve set up with samples of known concentrations and compare the absorbance reading of the sample to the standard curve/Good luck!