When you visit a brewery, you usually see a few numbers next to the beer name. You might see volume (measured in ounces), ABV, IBU, or maybe even SRM if you’re in a particularly hipster place or a place that is trying to peddle not-that-good beer.
Well, today I’m not going to discuss any of those. Instead, I’m going to discuss gravity, perhaps the most worthless term for casual beer fans who don’t actually brew.
Gravity in beer is fun because it almost doesn’t make any sense. So, let’s learn about beer gravity!
Beer Gravity: A Definition
I won’t use math to define beer gravity, although beer gravity is technically derived from mathematics. Instead, I’ll give you the word-writer’s version of gravity.
All beer is brewed, and during the brewing process the selected yeasts turn yummy sugars into alcohol. The magic of nature.
However, as yeasts eat sugar and turn it into alcohol, they also burp (I know this isn’t exactly correct, but bear with me. I promise it will make sense).
While it might not seem like a lot, mass is transferred from solid and liquid form to gas form during brewing. Stuff also burns off through another science called thermodynamics (I think) which means that the stuff in the beer also turns into gas. Basically, brewing yields less liquid at the end of the process than you started with.
Ok, on to gravity.
To get the gravity of a beer, you measure it twice – once during the brewing process (Original Gravity), and once after the brew is completed (Final Gravity). Both Original Gravity and Final Gravity would make great band names.
In terms of how you measure gravity — there are tons of ways to measure gravity, but everyone I’ve met uses a hydrometer.
So, when you measure the Final Gravity, you’ll see how much sugar was lost during the brewing process, meaning you’ll know how much sugar turned into alcohol. And that’s how you measure ABV! And also how you measure gravity.
What Does Beer Gravity Mean?
Beer gravity basically tells a brewer how alcoholic a beer is. The lighter the gravity, the more alcoholic a beer is.
I think now is a good time for me to note that a low-gravity beer, in gravity terms, is more alcoholic. However, in beer terms, this would be considered less alcoholic. And vice versa for heavy gravity beers.
I’ll break it down further. Imagine we made two beers from the same measurements of water, yeast, hops, and malts. However, we let one ferment for longer, yielding a higher ABV. This beer is technically lighter than the one that didn’t ferment for as long, meaning it would have a lower gravity. But we don’t call the high ABV beer low gravity! We call it high gravity!
The reason we call a high-gravity beer more alcoholic even though it’s technically less alcoholic is because someone out there wanted to make everything more confusing for everybody else.
So, to recap: low-gravity beer is technically more alcoholic but colloquially means less alcoholic. Easy, right?
Is High Gravity Malt Liquor Called That Because Of Beer Gravity?
I recently wrote about the difference between beer and malt liquor and it led me to wonder, does High Gravity malt liquor get its name because it’s more alcoholic?
Maybe! I didn’t research it.