Sugar Testing | Riversands Wines

Ever wondered how we Test the Sugar levels in our grapes for our Wine products?  Read on to find out how we use our Shiraz Grapes that go into making our famous FGP Port.

Why do we measure the sugar levels of our Grapes?

By measuring the sugar content of the harvested grapes we can define their level of ripeness. This process is essential to understand if any corrections or additions are needed before the fermentation process begins.

How do we Measure the Sugars Levels?

  1. A representative sample of Shiraz Grapes from different vines was collected.
  2. The grapes are then crushed in a bucket.
  3. Using a strainer we retrieve the wine juice for sampling and testing purposes.
  4. An eyedropper is used to obtain, and further place a sample onto the refractometer (or Brix meter).

The refractometer is an instrument that measures the refractive index of a solution (wine juice) to obtain the Brix. The meter is commonly calibrated at a temperature of 68 degrees fahrenheit ( 20°C).

  1. Peering through the Refractometer will then give the Brix ( °Bx) reading.
  2. We then conduct a further cross check with the Hydrometer by pouring some additional wine juice into a graduated cylinder (250ml).

The hydrometer measures the specific gravity (SG) of a liquid sample converted to Brix. The hydrometer is also used to test wine as it progresses through the fermentation process.

  1. Finally, we place the Hydrometer into the cylinder and wait for it to stop spinning before recording the hydrometer measurement.


For a Visual of this entire testing process click here!

What happens after Sugar Testing: the Fermentation process!

Fermentation is the transformation process of fruit into wine. This process involves yeast transforming the natural sugars into ethanol & carbon dioxide. Temperature fluctuations, the overall timing associated with the fermentation process, and the levels of oxygen all affect how the wine ends up in relation to the taste, colour, and aroma. The fermentation process predominantly stops in a natural way; when the yeast has consumed the sugars, that ultimately produces the alcohol in the wine.

What is Residual Sugar Testing then?

Residual sugar testing is the re-measurement of sugar however during the fermentation process, instead of prior to the fermentation process is complete. Residual Sugar refers to the leftover portion of sugar in the wine after the fermentation process. The more Residual Sugar leftover the sweeter the resulting wine will be.