ask dr. vinny

Hello there! I'm Dr. Vinifera, or "Vinny" for short. Ask me your toughest wine questions, from the technical aspects of winemaking to the fine points of etiquette. I hope you find my answers educational and even amusing. Looking for a particular answer? Check my archive and my FAQs. You can also follow me on Twitter: @AskDrVinny.


Dear Dr. Vinny,

What’s the difference between a refractometer and a saccharometer? Can wine producers use them as substitutes for each other?

—Kreetika, India

Dear Kreetika,

OK, let me see if I can answer this so the kids at home can follow along. Both a saccharometer and a refractometer are tools that a winemaker can use to measure the sugar content of grape juice. This can help in the vineyard when deciding when to pick grapes, as well as while making decisions during the fermentation process, as the sugar converts to alcohol. It’s kind of like taking your wine’s sugar temperature.

So how are they different? To start with, they work differently. A saccharometer is a type of hydrometer, which is an instrument that measures the specific gravity or density of liquids. I used one in high school science class—it’s made up of two parts, a cylinder where you put the liquid you’re measuring, and a weighted stem that floats on the liquid. In the world of hydrometers there are various specializations, including a saccharometer, which is created specifically for determining the amount of sugar in a liquid. The higher the sugar content, the denser the grape juice, and the higher the bulb will float.

Meanwhile, a refractometer measures the sugar in grape juice by measuring its refractive index, which deals with how much a light is bent or refracted. A refractometer can look something like a miniature telescope that you put a drop of juice in and then hold up to a light source to get a reading.

Besides the science, what’s the functional difference between the two? I hear saccharometers can be a bit temperamental when it comes to temperatures; because they’re based on floating, if you have a lot of solids in your grape juice sample, it can mess with the results. Saccharometers also tend to be made of glass and therefore more breakable, and they also need a fair amount of liquid to pour into the cylinder. Refractometers can fit in your back pocket, and because they only need a couple of drops to test, the juice density isn’t so much of an issue in the measurement.

So, to answer your question about using one as a substitute for the other, the answer is basically yes, but it depends on the circumstances—a saccharometer is better suited for use in a laboratory or other indoor setting, while a refractometer might be preferable while working outdoors, in the field.

—Dr. Vinny


Do you have a question for Dr. Vinny? Ask it here...

Wine Basics

We break down the basics—how to taste, serve, store and more. Plus:
» Maps of major wine regions
» Grape variety characteristics

How-to Videos

Learn to taste wine like a pro, pull a cork with flair, get great wine service in a restaurant and more

Wine Spectator School: All courses are FREE for WineSpectator.com Members

Learn from the experts and get the most out of each sip. Take one of our online courses or take them all—from the ABCs of Tasting to in-depth seminars on Food Pairing, California Cabernet, Bordeaux, Tuscany, Sensory Evaluation and more.

Browse our course catalog
Check out the professional wine sales and service courses
Learn Wine Forum: Got questions? Get answers

MEMBER LOGIN

= members only

Keep me logged in      Forgot Password?

Free Email Newsletters

Sips & Tips | Wine & Healthy Living
Video Theater | Collecting & Auctions

» View samples
» Or sign up now!
» Manage my newsletter preferences

Classifieds

The marketplace for all your wine needs, including:

Wine Storage | Wine Clubs
Dining & Travel | Wine Auctions
Wine Shops | Wine Accessories