How To Use A Hydrometer

Posted on April 5, 2010 by mike

What the heck is this little do-hicky that came with my homebrewing starter kit and what does it do, and WORST yet, how the hell do I use it?

This interesting little tool is called a hydrometer and comes in real handy for beginner, novice, advanced and expert homebrewers. The hydrometer has two main purposes. It tells you when your beer is done fermenting and it tells you how much alcohol is in your new beer. But how do you use a hydrometer? Let’s discuss.

How To Use A hydrometer

First things first. We need to learn how to take a reading. With a little direction, you’ll be an expert scientist in no time!

Drink you sample or discard it, but never put it back into the fermenter. Now what do you do with that reading?

Use it to find out when your fermentation is complete.

1. Take a sample of beer and place it in the tube that your hydrometer came in after you are done brewing and aerating your wort. This is done before pitching your yeast. Make sure you use a sanitized wine thief or other tool to acquire your sample. Mark that number down in your brewing notes. You will use this number to figure out ABV and if your fermentation is complete.

2. When you start to think fermentation is complete, take another sample. Again, be sure to use a sanitized wine thief or other tool to acquire your sample.

3. Measure that sample and note the number. Do not put the sample back into your fermenter!

4. Twenty-four hours later, take another sample and note that number.

5. Another 24 hours later, take another sample, note that number. If your number has not changed over 3 days your fermentation is complete and you are ready to bottle.

Use your hydrometer to tell how much alcohol by volume is in your beer.

1. Remember that first reading you took when you brewed up your batch of beer? Bring that number out because you’ll need it to figure out the final alcohol content.

2. Take a final sample from your bottling bucket. Once you moved your brew over go ahead take a sample right out of the spigot or use the number from step 5 where you determined your fermentation was complete.

3. Take a reading like describe above.

How to Calculate Alcohol By Volume

Calculating the alcohol content of your beer can be pretty easy if you just follow the following formula.

(Original Gravity – Final Gravity) X 131 = ABV%

There you have it. You can now not only take an accurate hydrometer reading, but you can use this tool to find out when your fermentation is complete and how much alcohol is in your beer!

Congratulations and happy brewing!

Side note:

Some people don’t bother using hydrometers and that is perfectly fine and dandy. They just like to brew and have done it enough to know when their beer is done. On top of that, they have a pretty good idea of approximetly how much alcohol is in their beers or just plain do not care. However, if you are like me, you like to know these things for future reference as you tweak and formulate recipes. Regardless, any new homebrewer should pay attention and use their hydrometer until they are comfortable with knowing when fermentation is complete. Otherwise, you may end up with some bottle bombs and those are no fun.

Just remember, have fun and enjoy!

Related Posts

• Getting Started Brewing My Own Beer
• How to Siphon Beer
• Homebrewing Tips
• No Brewing Makes Mike A Sad Panda
• Brew Day of Firsts