Thursday, September 13, 2018

Refractometer to Test Brix / Sugars

There are lots of ways to get an idea of the ripeness level of your grapes leading into harvest.

The easiest is to taste the grapes to see how sweet they are and what the acid is like. Problem is if your new at this then you dont really have a baseline of previous years experience to assess it against.

Another way is to check the colour and hardness of the seeds in the grape. If the seeds are brown and crack hard when you bite on them then you know the grapes are getting ripe but experience is key here again and the brown of the seeds is not universal for all grapes relative to how ripe they are. Similarly the bunch stem usually turns brown and hardebs off.

One of the most accurate ways is to test the sugar ot brix level of the grapes with a refractometer. These instruments cost about $100 and provide a fairly accurate reading of the sugars in a few drops of grape juice. I taje a sample of about 3 grapes from different parts of the cluster and average the numbers out.

Brix is a measure of sugar content in the grape juice and ripe grapes will usually have between 18 and 24 brix depending in the variety. So in converting brix to alcohol content, 1 brix gives you roughly 0.55-0.6 % alcohol, so 20 brix gives you wine with roughly 11-12% alcohol when fermentation is complete.

I put a small video here to show how the refractometer works. Not the best video but you'll get the idea when you see this.