Here’s how you can find out the alcohol content of your beer
More often than not, if there’s one thing you are uncertain of when you lift a glass of beer, is the alcohol content in it. And if you’re just as curious as we are to determine what the percentage of it would be in your drink, here’s an easy way to find out. Most breweries do not provide such information, and if you are set out to figure it out yourself, then here is an easy formula for it – The Alcohol Percentage by Weight (ABW) equals 76.08 times of Original Gravity (OG) minus the Final Gravity (FG), divided by 1.775 minus Original Gravity i.e. ABW = 76.08 (OG-FG)/(1.775-OG).
For those using Alcohol by Volume (ABV) can calculate using ABV = ABW (FG/0.794).
You cannot find out the alcohol content of the drink unless you have the Original (starting) gravity. However, you can calculate the Final Gravity on your own if you have a hydrometer (easily available at any homebrew store). Simply warm the beer to about 60F and pour it back and forth a couple of times to cut down the carbonation. Now, use the hydrometer to find out the FG and calculate the percentage of alcohol your beer contains. So, stop guessing and find out for yourself. Cheers!