Refractometers are scientific tools designed to measure light refraction through liquids. They are usually found in laboratories, testing plasma levels and identifying the makeup of precious stones—definitely not something used in the coffee world……until now.


The Coffee Refractometer

Similarly to a regular refractometer, a coffee refractometer can be used to identify extraction amounts and measure caffeine concentration in coffee.

It already has a presence in some places thanks in large part to VST Inc.—the company responsible for the first ever coffee refractometer (they are now on the 4th generation!).  VST’s refractometer is specific to measuring certain elements of coffee, but builds upon the original technology of the scientific instrument. VST’s coffee refractometer utilizes proprietary software, VST CoffeeTools, which results in a product that is easy to use and understand. The device is starting to have a real presence in the professional coffee world—check out this one from Pocket Coffee.


How Do You Use It?

When used properly, a coffee refractometer is a beneficial way to zero in on quality and precision in order to achieve the perfect tasting cup of coffee. If you own one of these or are interested in trying one out, here’s how to use a coffee refractometer:

  • Drop a few drops of coffee onto the sample well.
  • The well will light up and shine through the coffee sample.
  • The refractometer should bring up a reading of the total amount of dissolved solids (TDS).
  • Using that reading in tandem with your brewing recipe (the amounts of coffee and water used) and final beverage volume will allow the refractometer to measure and display the coffee’s TDS and extraction yield.
  • Once you have all this information, you can adjust the recipe based on your preferences; or, if you’re a barista, this will allow you precision in making a coffee exactly the way the customer ordered.



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Coffee Refractometer Overview


  • PC/Mac versions of CoffeeTools offer more ways to guarantee precision and more in-depth analysis.
  • Great tool for coffee businesses like roasteries and coffee shops
  • Data provided is useful when evaluating a new coffee from potential sellers. For example, shops using a coffee refractometer would be able to tell a coffee producer whether a different grind would improve their coffee.
  • Can tell if coffee is too strong or too weak + whether it’s under or over-extracted.


  • Expensive. The software runs from $29-49 on mobile and up to $150 for PC/Mac versions. The refractometer and everything that comes with it ends up costing around $800.
  • Impractical for individual home use (unless you’re just interested in learning how to use one).
  • Can tell how much is extracted, but not what specifically was extracted. Pro tip: You can combat this issue by putting your palate to work—under-extracted coffee will have a sour taste while over-extracted will have an extreme bitterness.


Still not brewing your perfect cup?

Extraction isn’t everything! You might be brewing a coffee that isn’t roasted to your preference.

If you’re tasting fruity, floral notes and wishing for chocolatey, nutty, roasty goodness, a Medium or Dark roast would be a much better fit! Our Medium to Dark plan is made for you.

Conversely, if you’re wishing you tasted more of those unique fruits and florals, go with a lighter roast (and try the pour-over technique for best results!).  You’d enjoy our Light to Medium plan.



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