Knowing how to test for alcohol content is important for the wine or beer maker trying to establish the appropriate alcohol content of a beverage. It is also important for those who wish to know the alcohol consumption of other beverages, such as parents who are concerned about their teenage children. The testing for alcohol content of wine or beer is not complicated. All that is required is a hydrometer and a little math. Testing other beverages for alcohol consumption is also easy; there are simple tests that are readily available and the testing process is quick and painless.
Fill a test jar (a deep vessel, chimney-shaped), that will accommodate about ½ to 2 cups with water.
Float a hydrometer in the test jar and make sure that it rests at 1.000; this is the normal specific gravity (SG) reading of water. Sugar dissolved in water will read heavier, as it is heavier than water, and a liquid measured after fermentation will read lighter or equal to that of the water.
Take an "OG" reading of your wine or beer before adding yeast using a hydrometer and take note of the number. The OG refers to the original gravity reading of your wine or beer before you add the yeast and start the fermentation process.
Wait for the wine or beer to ferment and take a second reading with the hydrometer. This number is the "FG" or final gravity. Note this number.
Subtract the OG from the FG.
Multiply the resulting number by 131 to get the alcohol by volume content or ABV.
Purchase a urine test kit. Test kits can readily be acquired from the internet and also from some local pharmacies. Good sources are outlets which cater to parents interested in drug/alcohol testing for their teens.
Have the individual being tested supply an adequate sample using the cup provided in the test kit.
Ship the collected sample to a lab to be tested according to the packaging directions. Some kits can also be dropped off at a local pharmacy or doctor's office for processing. The length of time to obtain the results will vary depending on the amount of samples the lab has to process.
Buy a Breathalyser from a business that sells these devices; the internet is full of places that will offer these for a reasonable price.
Have the person being tested blow into the machine for the required amount of time in order to acquire the needed sample.
Wait for a few seconds after the machine signals a completed test. Read the results from the display screen.
Obtain a testing kit from the internet that will allow you to take a person's saliva for testing.
Use the swab that is included in the testing kit to obtain a sample from the inside of the person's mouth. The inside of the cheek is usually the best place to obtain this sample from.
Ship the collected sample to a lab and await the results. Result turn-around times can vary from a couple of days to a week depending on the amount of tests the lab has to process.
Hydrometers are calibrated to work correctly at about 15 degrees Celsius / 59 to 60 degrees Fahrenheit; at higher temperatures the liquid thins and the resulting readings are slightly lower.
Breathalysers are known to often give false readings, and this is not the preferred testing method.