Friday, September 21, 2018

Through the refractometer window.

Today was the first sugar-sampling of the season.  Using my trusty refractometer, to ascertain the level of sugar in a small sample of Pinot grigio juice, I got a reading of 23.2 °Brix.  A good start, but the flavours aren't quite there yet.
My handheld refractometer is a very useful instrument to have around, it helps makes my job easy.  A large proportion of the soluble solids in grape juice are sugars and it is the ripeness of the fruit (the percentage Brix) that I am trying to determine.  (Fructose and glucose are the main sugars in grape juice, combining as the disaccharide, sucrose.)  The sweeter the juice, the more it will bend the light that passes through it (refraction).  It is the angle of the light, the refractive index, that when viewed through the eyepiece of the refractometer, gives the level, or measurement, of sugar (i.e., grams of sugar per 100 grams of juice) in the sample.  See, easy peasy.  I'll leave the harder part to Vinomaker; determining the acid content and pH.
It is almost harvest time.  I predict I have a busy month ahead of me.