The Basics in Grape and WIne Chemistry

My brother and I went to Prosser and enjoyed a day learning about the basics in wine and grape chemistry. We visited the Washington State University Extension campus to learn and get some hands on experience in the tests used to measure various components of grapes and wines used in the winemaking process. These components included: Sugars, acids, ethanol, and SO2. We completed the following tests:

Brix through use of the refractometer, densitometer, hydrometer, and rebeline methods.

Above is a PH meter, we used this to measure the PH in the grape juice, we coupled this with the titrating process to determine titratable accidity.
This device is the refractometer used to measure the Brix in the grape juice. It gets confused when you are testing wine because alcohol messes with the results.

This glass bobber is a hydrometer and tests brix using the buoyancy of the liquid.
This device is the Anton Bar densitometer, it is the easiest and most accurate way to test for Brix.
Here we have an ebelliometer which measures alcohol content of wine.
This device was used to airate and oxidate the free SO2 out of the sample wine.

The above image is an example of paper chromatography similar to the ones we observed on our trip. This image is from the www.travessiawineblog.com website. This image showl ML fermentation is complete on 4 of the wines on the left but not complete on the 4 wines on the right.

Acids through pH, titratable acidity, paper chromatography.

Ethanol using the ebulliometer

Free and total Sulfur dioxide through aeration/oxidation

The course was taught by James F. Harbertson jfharbertson@wsu.edu


Resources:
CAWGG California association of wine grape growers
WAWGG Washington association of wine grape growers
winebusiness.com
Vitis journal
Australian tech conference

Instrument resources:
Fisher scientific
VWR
Hanna Instruments

Best lab book available:
Techniques for Chemical Analysis and Quality Monitoring During Wine Making by Patrick Iland

Other good books include:












Handbook of Enology vol. 1 and 2 by P. Ribereau-Gayon















Magazines Wine business monthly
wines and vines

People to know in the industry:

Grandall Grahm Bonny Doon www.bonnydoonvineyard.com/
Professor Markus Keller, PhD. Viticulture at WSU.
Katie Perry at Tildio www.tildio.com

Sanitizer used at WSU Winery:
Poroxiclean