Method for determining the volume ratio of ethanol alcohol in liquor - Master's thesis - Dissertation

First, the purpose of the experiment 1. Understand the determination method of the alcohol content of traditional liquor. 2. Master the principle of measuring the sample content. 3. Learn to use the refractometer.

There are many degrees of liquor, whether it is low-grade or high-alcohol, its degree contains the meaning that many people are not very clear. The alcoholicity of liquor refers to the percentage of alcohol in liquor, that is, the content of alcohol. For example: 60° white wine means 60% alcohol, the remaining 40%

Basically it is water.

In China, there was no wine table in the early years. The determination of alcohol consumption was determined by looking at hops and using fire shochu to determine the alcohol content of the wine. Methods as below:

1. Look at the hops. Put a certain amount of water on the wine, take a spoonful of a pot, use a spoon to slowly pour from the high to the low into the basin, observe the size, uniformity and retention time of the wine "flower" falling in the wine tasting basin. The length of the alcohol to determine the content of the ingredients. This method is accurate to 90%.

2. Burn with fire. The white wine is simmered in the sputum, ignited and burned. After the fire is extinguished, look at the amount of water remaining in the sputum, and determine the alcohol content of the wine according to the amount of water. This method is often less accurate because it is often affected by external conditions.

After the founding of the People's Republic of China, the national use of the "wine table", the use of wine meters to determine the alcohol content of liquor. The method is to take a glass measuring cup, the cup is filled with the white wine to be measured, and the sample of the 3ML white liquor is extracted and dropped in the refractometer and the concentration meter prism. After 3 seconds, after the data measurement is stable, the measuring tool can be viewed. Alcohol volume ratio content.

In ancient times, without advanced analytical tools and instruments, the method used by brewers to detect alcohol content was to use fire. They mixed the same amount of wine and then ignited. If there is no fire, it proves that the alcohol content is low. If the flame is very bright, the alcohol content is high. If the flame is medium and blue, it means that the alcohol content is medium. This method is called "Proved" in English, and it has evolved. The amount of alcohol in wine is expressed by "Proof", which means the amount or purity of alcohol. There are currently three types of alcohol expressions used internationally. Standard alcohol (Vol), Sikes, Proof, when 1 ml of alcohol per 100 ml of liquor, the alcohol is 1 degree "1% Vol" or "1GL"

 Liquor is measured by alcohol. The normal temperature of white wine is 20 ° C, put on the alcohol table, if the wine temperature is lower than 20 ° C every three degrees plus one degree of alcohol, above 20 ° C every three temperatures minus one degree alcohol. 

The following is a refractive index data sheet for liquor at 20 ° C:

Second, experimental instruments and reagent instruments: PAL-33s ethanol refractometer, a mirror paper, filter paper. Reagents: absolute ethanol, distilled water, white wine. Third, the operation steps (1) preparation of the ethanol-water system solution: ethanol (V / V) containing 10%, 30%, 40%, 50%, 60% five working solutions. PAL-33s ethanol refractometer, instrument cleaning, calibration: scrub the prism with cotton balls, and dry. Use a dropper to add 3 - 5 drops of distilled water below. Note: the dropper should not touch the prism. Press the "START" screen to display "0.0" to dry the test sample. If it is not zero, press "ZERO" to zero. Then dry and test again. (2) Determination of the sample: 1. Clean the surface of the prism; 2. Drop about 0.3 ml of the sample to be tested onto the surface of the prism; 3. Press the “START” button; 4. The instrument displays “---”, then displays the Brix value and The temperature 5.Brix value will continue to display for 2 minutes. To shut down, press and hold the START button for more than 2 seconds; 6. Wipe off the sample with a paper towel or gauze, wash the residual sample with water, and wipe the prism surface and instrument. 4. Precautions [Caution] ● Do not use metal spoons. As such, the metal can wear or damage the prism surface. ● The sample temperature must be the same as the ambient temperature. If not, adjust to the ambient temperature before starting zero adjustment. ● The body (except the metal groove) should not touch the sample exceeding 30 °C, otherwise it may cause deformation of the outer casing, which may affect the waterproof performance of the instrument. When measuring high temperature or viscous samples, please be careful not to spill or spill metal grooves, please Use a small spoon to load the prism surface. Avoid using water above 30 °C to clean samples that are dehydrated and hardened on the prism surface. The correct cleaning step is to carefully wipe the sample with a skim gauze soaked in hot water. It is forbidden to contact the hot water in the outer casing, otherwise the outer casing may be deformed, which may affect the waterproof performance of the instrument. If the sample displays “nnn” warning message on the screen, cover the sample tank by hand and press the start button again. Always do a thorough scrub and check.