A refractometer is commonly used in both the beer and wine industry as a tracking tool for fermentation.
While it’s not an essential for home brewing, using a refractometer as part of the process is an effective method of measuring specific gravity. This is a way of showing how dense the liquid is and how much sugar content it has.
Specific gravity is the ideal starting point.
We’ll look today at what these nifty devices are and how they can help you enhance your home brew.
What is a Refractometer & What does it Measure?
We need to get started with a refractometer definition.
They are a simple optical device used to measure the concentrations of liquids.
Unlike other instruments, you can analyze a liquid based on just a few drops with a refractometer making it ideal for use in home brewing.
“Refractometers are commonly used for quality control purposes in industrial settings, particularly in the food and beverage industries.In addition, home-brewers may use a refractometer to determine the specific gravity of their beer.”
– Susan Berg, Sciencing
Refractometer vs Hydrometer
When you’re looking to measure specific gravity, you have several options at your disposal with the lead contenders the very basic hydrometer and the more efficient and versatile refractometer.
We’ll pit hydrometer vs. refractometer now to see which makes a better fit for your home brewing enterprise.
- Hydrometer: A hydrometer works by displacing liquid according to density and then measuring the liquid displaced. While inexpensive and effective, hydrometers need to be tweaked based on temperature and call for large sample sizes. There’s also a degree of waste involved and batches can become contaminated. Hydrometers are perfectly acceptable if you’re new to brewing.
- Refractometer: Rather than measuring the density of a liquid directly, they calculate sugar content based on the refraction of light through your beer. While pricier, you can use much smaller sample sizes without temperature becoming such a niggle. If you’re an intermediate or more advanced brewer, it’s well worth making the modest investment in one of these.
We’ll look now at their uses and how to read a one.
How Does a Refractometer Work?
Before we glimpse at the process of refraction to help you better understand refractometers, check out how easy it is to use one of these awesome little tracking devices…
- Place 3 drops of solution on the prism of your refractometer.
- Shut the cover.
- Look toward a bright light through your refractometer.
- Measure where the color starts to separate to check for sugar content.
- Light bends to a different degree according to the substance it passes through. When sugar is added to water, it will bend more.
Refractometers measure this bending with a prism and source of light to determine the amount of sugar your sample contains.
The Brix scale is used to measure specific gravity with a refractometer.
What Is Brix & What Does It Mean?
Brix is a scale of measurement is used to show the sugar content in a liquid. 
One degree Brix translates to 1g of sucrose in 100g of solution. The strength is shown as a percentage by mass.
How To Calibrate a Refractometer
Before you get started with your device, you’ll need to calibrate it for best results.
Luckily, this is straightforward.
- Lift up the sample plate.
- Add 3 drops of distilled water.
- Shut the plate and let the water spread across.
- Make certain there aren’t any bubbles and allow the brewing refractometer to hit room temperature.
- Take a reading with your device held up to natural light.
- Adjust the setting using the screw so that it reads zero using distilled water.
How To Use a Refractometer For Beer Making
Once you’re familiar with how to calibrate a beer refractometer, using one for beer making (52brews.com/how-to-make-beer) is not much different.
- Open up the sample plate again.
- Add a few drops of wort. Wort is the pre-fermented infusion.
- Make sure this is allowed to cool to room temperature for maximum precision.
- Close the sample plate and check for bubbles.
- Measure against a natural source of light.
There are other measurements besides Brix such as RI (refractive index). There are many online tools to help you switch from one measurement scale to the other without any tricky calculations. 
Refractometers are used for a range of applications beyond brewing and they come in 4 main variants:
- Handheld analog
- Handheld digital
- Abbe or lab
- Inline process refractometer
While a brewing refractometer is an undeniably useful tool when you’re brewing beer, it’s not without its drawbacks in the form of conversion between scales of measurement.
Refractometers are calibrated to measure how much sugar there is in a clear sample of water. This type of sugar is sucrose while the sugar in barley beer is maltose.
Use a tool such as BeerSmith to avoid some really nasty calculations.
While they seem like simple pieces of kit, beer refractometers are precision instruments and as such need proper care and maintenance.
Think about these areas if you want long service from your device…
- Keep away from wet environments.
- Clean and dry thoroughly after each use.
- Do not evaluate samples your refractometer is not intended to measure.
- Handle with care at all times and store somewhere with a constant temperature that does not vary by more than 5 degrees Fahrenheit over the course of the day.
Take these points into account and you should get many years of happy use from your device.
What Are You Waiting For?
We trust you’ve found this exploration of refractometers and the role they can play in the brewing process was useful and has given you a few pointers on whether or not it makes sense for you to add one to your arsenal.
Although hydrometers can serve as a substitute, if you’re serious about your beer, it pays to pick up a refractometer so you can dial in the consistency more accurately.