Their ca Take another reading with the hydrometer once the fermentation has completed. This reading should be somewhere around +1 to -1 on the Potential Alcohol scale. Original gravity (abbreviated OG) is a measure of the fermentable and un-fermentable substances in a beer wort before fermentation. Finds ABV based on gravity change. The basic formula used by most homebrewers is pretty simple: ABV = (OG - FG) * 131.25. By comparing these two gravity hydrometer readings you can determine your wine’s alcohol level. While this is very close to the truth, it is not 100% accurate. You can determine the alcohol in your wine with a simple tool called a hydrometer. Many homebrewers operate under the false assumption that they are measuring the sugar content of the wort when they measure specific gravity. A beers alcohol level is measured in Alcohol by Volume (ABV), it is the calculated amount of the total volume of liquid that is alcohol. A hydrometer identifies the specific gravity of a liquid, which is (...) Read More » This is due to the fact that alcohol is less dense than water; therefore, as your wort ferments (and the sugars are converted to alcohol), the density of the beer decreases. If you have produced your own homemade wine, then you may want to know the alcohol content. ABV = alcohol by volume, OG = original gravity, and FG = final gravity. The reason is alcohol has a different refractive index than water, causing many to believe the refractometer is useless once fermentation starts. Distilling and brewing hydrometers make the two types of the hydrometers available. I have a partner who occasionally buys ingredients with me. The Specific Gravity of a liquid is that liquid’s density compared to water. The general steps to calculate SG using a potential alcohol measure are as follows: 1. To understand how to calculate the original gravity of your homebrew we first need to understand specific gravity. How to Use a Hydrometer The above is a scientific tool, and it is used to measure the alcohol content present in the mash. The difference between the two allows you to calculate the alcohol by volume. Homebrewing – Measuring Alcohol Content of Your Beer. The work of the device primarily measures liquid density in water relation. The density of a liquid is often measured in unit of specific gravity, where water has an approximate density of 1.00 g/mL or a specific gravity of 1.000 at 60F. Working out the amount of alcohol in the fermented brew is pretty easy, given that the amount of C02 produced per gram of ethanol produced during fermentation is 1.05. During fermentation your yeast will have eaten the sugars in your wort and pooped out carbon dioxide and alcohol (this is a very complex process where the yeast use a wide range of enzymes producing many by-products, way more in depth than we have time for here). Somehow we neglected to take an original gravity reading. Write this number from the gravity hydrometer down and save it for later. Measure … This is an easy test to do, and it is something many people like to know before they start drinking. When it is placed in a liquid, it will sink to a particular depth, which depends on the liquid’s density. Specific gravity is a measure of density. He and I were brewing a summer beer together a couple of weeks ago, and we always write down our times, ingredients, temperatures, etc. By considering the original gravity, the brewer or vintner obtains an indication as to the probable ultimate alcoholic content of their product. 2. Normally, I wouldn't sweat it, but he is rushing me to bottle this weekend. A hydrometer is designed to measure density, and it can be used to determine the alcohol content in beer. Knowing the alcohol content of your homemade wine can save a night from being disastrous. Those substances are often the sugars that will be converted to alcohol during the fermentation process.