Agriculture Blog

This summer, Dr. Chin-Feng Hwang’s graduate students, Daniel Adams and Surya Sapkota, began sampling berries for juice analysis from vines resulting from their grape breeding work. They want to relate berry and wine quality to particular genes in grapevine.

In the past, we have observed differences in juice analysis results between species related to the processing technique used. We decided to run a simple trial looking at three berry processing methods and four types of grapes. It is important for the analysis results to represent the juice that would result from actual pressing at the winery. This trial is of interest to grape growers and was recently published in the Iowa State Wine Grower News #345.

The Wine Grower News has a circulation of over 1,700 in 11 countries and is a great way for our students to help the grape and wine industry with their findings.

Surya Sapkota collects berry samples from Norton grapevines. It is important to collect an equal number of berries from each side of the trellis. — Surya collects berry samples from Norton grapevines. The students tested *Vitis aestivalis* ‘Norton’, *Vitis labrusca* ‘Catawba’, *Vitis vinifera* ‘Cabernet Sauvignon’ and the mixed hybrid ‘Chambourcin’.

This is the stomacher machine - one of the three methods used to process juice. The other two were hand pressing in a ziploc bag and hand pressing then wringing through cheesecloth. — This is the stomacher machine – one of the three methods used to process juice. The other two were hand pressing in a ziploc bag and hand pressing then wringing through cheesecloth.

Daniel and Surya analyze the juice processed by three different methods for sugar content, pH and acid content. — Daniel and Surya analyze the juice processed by three different methods for sugar content, pH and acid.