How is alcohol strength measured?!
How is alcohol strength measured?
Answers:
Most of the world measures alcohol as a percent of volume (abv). In the U.S., alcohol in beer is measured by weight (abw). Since alcohol weighs roughly 20% less than water, abw measures appear 20% less than abv measures for the same amount of alcohol. In Europe, beer strength tends to be measured on the basis of the fermentables in the wort.
Until recently, Britain used OG (original gravity), which is 1000 times the ratio of the wort gravity to that of water. Thus a beer with an OG of 1040 was 4% more dense than water, the density coming from dissolved sugars. You can generally take one tenth of the last two digits to estimate the percentage alcohol by volume once the dissolved sugars are fermented. In the example used, the abv would be approximately 4% (40/10 = 4%) Currently, British beer is being taxed on its actual %ABV rather that the older OG so you'll often find both displayed.
Continental Europe tends to uses degrees Plato. In general, the degrees Plato are about one quarter the last two digits of the OG figure. Hence, in our example above, the beer would be 10 degrees Plato. To get the expected alcohol by volume, divide the degrees Plato by 2.5.
In the US it is listed by "Proof" on a bottle. It is based on the percent of alcohol by volume in the particular liquor. The percent of alcohol is half the "Proof" number. For example, 86 Proof whiskey is 43% alcohol by volume. Illegal moonshine may go as high as 180 proof (90% alcohol) but most consumable liquors are 80 - 86 proof.
Great answer above. I would only like to add a little bit about "proof", since alcohol is often described in these terms.
A liquor's proof is a measure of the ratio of ethanol by volume. Proof varies from country to country. In some European countries, proof is just a percentage. (ie: If a liquor is "40 proof", it is 40% ethanol and 60% water and other ingredients.)
In the US, a liquor's proof strength is equal to two times its ethanol content. (ie: An "80 proof" Kentucky bourbon is 40% ethanol by volume.) This term comes from the early 18th century in the US. Bourbon distillers would often hold conferences to compare their goods and discuss industry issues (pricing, tarrifs, supply, etc.). At these conventions, distillers were required to "proove" the alcohol content of their liquor, to proove that they weren't selling a watered-down product. At the time, a 50% concentration was considered ideal. Liquor that hit this mark was described as "100 proof", and the term stuck.
IN BEER :
Use the "balling scale" on a hydrometer and then do some multiplication . . .
Multiplying the difference between initial balling reading and final balling reading by the number .42 will give you an approximate measure of the alcohol content of your beer by *percent weight*.
To convert percent alcohol by weight to percent alcohol *by volume*, multiply by 1.25.
Subject: 2-1. How is alcohol strength measured?
Most of the world measures alcohol as a percent of volume (abv). In the U.S., alcohol in beer is measured by weight (abw). Since alcohol weighs roughly 20% less than water, abw measures appear 20% less than abv measures for the same amount of alcohol. In Europe, beer strength tends to be measured on the basis of the fermentables in the wort.
Until recently, Britain used OG (original gravity), which is 1000 times the ratio of the wort gravity to that of water. Thus a beer with an OG of 1040 was 4% more dense than water, the density coming from dissolved sugars. You can generally take one tenth of the last two digits to estimate the percentage alcohol by volume once the dissolved sugars are fermented. In the example used, the abv would be approximately 4% (40/10 = 4%) Currently, British beer is being taxed on its actual %ABV rather that the older OG so you'll often find both displayed.
Continental Europe tends to uses degrees Plato. In general, the degrees Plato are about one quarter the last two digits of the OG figure. Hence, in our example above, the beer would be 10 degrees Plato. To get the expected alcohol by volume, divide the degrees Plato by 2.5.
http://www.beerinfo.com/rfdb/faq.html#li...
Since alcohol is lighter than water, it is measure in percentage of volume.
the actual " proofing" originally involved black gun powder and a portion of the drink to be tested. If the combination flashed, it was not "proofed". If it burned with a steady blaze, it was " proofed". Combination was fairly close to the 43% we generally see on most whiskey now.