A tour of the ways of measuring the force of an alcoholic beverage
When we enter the world of beers and spirits, we find numerous labels that promise to give us a clear idea of how much alcohol we have in the cup. However, those figures do not always say the same, and that can generate more doubts than certainties. How can we understand those percentages and what really mean for our enjoyment? The key is in two measures that, although similar, are not the same: the ABV and the Abw.
What is each one about? The ABC of alcohol on labels
The power of volume: ABV
The term ABV, or volume alcohol, indicates how much percentage of the total liquid we drink is pure ethyl alcohol. In simpler words, if you have a beer with 8.5% ABV, that means that 8.5 milliliters of alcohol are contained in every 100 milliliters of that drink. It is the most common and universal way to express the strength of a drink in the alcoholic beverage industry, partly because it is easy to understand and compare between different products.
The weight also counts: Abw
For its part, the Abw, or alcohol by weight, talks about the amount of alcohol in relation to the total weight of the drink. That is, if a beer has 8.5% Abw, in every 100 grams of the liquid, 8.5 grams correspond to ethyl alcohol. Here, the difference lies in how that same force is measured, since the weight does not always translate directly into volume, especially in liquids with different densities.
Why do these differences matter? A matter of liquid mathematics
The relationship between ABV and ABW is not simple, although many industry standards assume that they are linearly related, with the ABW being approximately 80% of the ABV. However, in reality, this relationship varies and is not exactly proportional in all ranges. For example, in the United States, many beers recorded with 3.2% of alcohol in volume correspond to 4% by weight. This is due to historical and tax issues that have their roots in the laws of the time of dry law.
Mathematics about alcohol: How is all this calculated?
The analysis from the volume of alcohol
To determine how much alcohol there is actually, we can break it into its main components: alcohol and water. The idea is that the volume of alcohol, when divided by the total volume of the drink, gives us the percentage of ABV. But, to understand numerical relationships, it is more useful to make it weight using specific densities. Ethyl alcohol has a density close to 0.789 kg/l, while water, in normal conditions, reaches 0.998 kg/l. These figures seem small, but they change the way we interpret the labels.
The weight of alcohol and the relationship with ABV
A simple formula to calculate the ABW from ABV, and vice versa, implies understanding how these weights and volumes relate. It has to do with how alcohol and water interact in the total mass and how these proportions are reflected in the labels. If we multiply the ABV by a factor of approximately 0.8, we will obtain a good approximation of the Abw, although in some circumstances the difference can be significant, and even more in drinks with high concentrations.
And what about beers? The truth behind the percentages
One of the most interesting curiosities is that many beers labeled with 3.2% in volume actually contain 4% by weight. This is due to the way the contents are measured in different countries and to historical rules that still persist. The result is that a beer that seems to have less strength, can actually be more powerful when it becomes a weight of weight. Thus, this little difference can mean a great variation in the perception of force, and also in the experience that is sought when taking it.
Final reflections: beyond the number on the label
What ends up being important is that we understand that the figures in the bottles do not always reflect how many glasses can be filled with that amount of alcohol. Science and history behind these measures teach us that alcohol content can deceive if it is not interpreted carefully. The next time you choose your favorite drink, remember that 4%, that 8 or that 12, are only figures that contain a whole story, a tradition and also a liquid art of knowledge that continues to evolve.
