Hi guys, today we will learn how to measure the gravity in our brew.
Gravity helps us in knowing the alcohol content in our drink.
There are two instruments which can tell us the specific gravity.
Firstly we have a hydrometer. 
Hydrometer is made out of a glass tube and looks like this.
It has readings on it's sides and we have to dip it in the liquid. 
The level at which it floats, tells the initial gravity. 
If you would like to but one, you can check the link in the description below.
And secondly, we have a refractometer.
Refractometer does the same thing but it doesn't need a lot of liquid to be dipped in.
Refractometers can tell the gravity just with a drop or two.
Here I have a pitcher full of water.
We will test the gravity in both the instruments.
But first, I will sanitise the hydrometer with its graduated cylinder  
and a dropper which I will use with the refractometer.
If you want to find out how to sanitise our equipment, 
click on the I button and watch the video tutorial.
So now as I have santised everything,
I will fill up the cylinder with water.
Remember to leave some space empty on top or you'll overflow the liquid inside.
Water has a gravity of 1.000 and as you can see,
the same is shown by our hydrometer.
Now I'll move the cylinder aside.
I'll give the refractometer a wipe and then take a few drops of water with the dropper.
So the blue part that we can see in the front is the area we will be putting the liquid on.
Just a few drops to spread them evenly. 
Now, I'll just close the lid and point it towards some light. 
As you can see, the refractometer shows us the same gravity as the hydrometer.
Now let's increase the gravity and check again.
Here I will add some sugar to increase the gravity.
Just a few points to learn until the sugar gets dissolved.
Our initial gravity or original gravity will be the gravity before fermentation
and the final gravity will be the gravity after fermentation.
Original gravity will always be greater than the final gravity.  
I know there's still some sugar left below. But it won't affect us.
We can test it's gravity. I'll simply pour the liquid again and put the hydrometer.
This time, the hydrometer shows an approximate reading of 1.047.
Let's check for the refractometer as well.
It shows the same reading of 1.047, just as the hydrometer.
The formula to calculate the alcohol content in a brew is on the screen.
As you can see, you need to pour a lot of liquid for hydrometer. 
I highly recommend you to go for a refractometer if you're not on a very strict budget.
Otherwise, please do get a hydrometer. It's very essential to read the gravity.
You can find the link for both in the description below.
