Can anyone explain beer gravity?
None of my stuff even mentioned it.
Gravity measures the density of a liquid. Pure water has a specific gravity of 1.000 at room temperature. Anything dissolved in the water will change it’s specific gravity. Sugars will raise this number, alcohol will lower it.
When you take your original gravity reading of your wort prior to fermentation (aka “OG”), this number represents the dissolved sugars in your wort. As the yeast eats the sugar and turns it to alcohol, the gravity will decrease. When the yeast have stopped consuming sugar, you have reached your terminal, or final gravity (aka “FG”). You can then use these values to calculate how much alcohol is in the finished beer.
I’m really new to all this myself. This link has tons of info.
http://www.howtobrew.com/You have to enter. Then at the bottom of the page it has the Appendix section.
Appendix A is using a hydrometer and gravity readings.
[quote=“erockrph”]Gravity measures the density of a liquid. Pure water has a specific gravity of 1.000 at a specific temperature as noted on the hydrometer. Anything dissolved in the water will change it’s specific gravity. Sugars will raise this number, alcohol will lower it.
When you take your original gravity reading of your wort prior to fermentation (aka “OG”), this number represents the dissolved sugars in your wort. As the yeast eats the sugar and turns it to alcohol, the gravity will decrease. When the yeast have stopped consuming sugar, you have reached your terminal, or final gravity (aka “FG”). You can then use these values to calculate how much alcohol is in the finished beer.[/quote]
Fixed that for you.
+1 on the how to brew website, its a great resource. In fact you should just buy a physical copy of the book, very useful for brewers of all skill levels.
One more thing on gravity: one of the most common newbie posts is when a new brewer measures the OG of a batch and is concerned that their gravity measured way off. Its not. Its fine. If you’re an extract brewer, provided you used the right quantity of extract and right volume of water, your starting gravity will be exactly what the recipe was designed to be. Partial boil brewers often have trouble measuring gravity accurately because the top up water you add at the end doesn’t mix perfectly with the concentrated wort. Depending on how you pull the sample the gravity could read higher or lower than it really is. Don’t worry about it. This isn’t a problem when measuring final gravity, as by the time fermentation is done things will be evenly distributed.
