By Blake Jackson
Making wine involves numerous factors, including grape composition, microbial activity (like yeast), and environmental conditions such as temperature, rainfall, and soil quality.
Traditionally, researchers use pilot-scale fermentations of around five gallons to study aspects like grape quality and yeast performance. However, these experiments can be time-consuming and costly.
A recent study by Penn State food scientists suggests that a smaller, more efficient method microvinification, using just 50 milliliters (about a quarter cup) offers a reliable and cost-effective alternative for analyzing wine chemistry.
“With proper replication - doing enough repeated tests - microvinifications can give trustworthy results,” said Misha Kwasniewski, senior author of the study and associate research professor of food science at Penn State’s College of Agricultural Sciences.
“These small-scale tests can be a powerful, cost-effective way to improve research accuracy, predict how wine will turn out based on grape chemistry and support commercial wine-production decisions.”
Published in the American Journal of Enology and Viticulture, the research challenges common industry skepticism about microvinification. Concerns have long included variability, excessive oxygen exposure, and inconsistent results.
Motivated by these doubts, Kwasniewski and lead author Ezekiel Warren, a doctoral student in the Department of Food Science, evaluated factors such as oxygen levels, fermentation temperature, and grape skin contact during fermentation.
Their analysis included oxygen absorption, phenolic compounds (impacting color, texture, and bitterness), and aromatic compounds (contributing to flavor and aroma) in both small and standard-sized fermentations.
The findings showed that microvinifications maintained consistency and were not adversely affected by oxygen. Key variables like temperature, cap management, and maceration time influenced outcomes similarly in both batch sizes.
The team used Chambourcin and Noiret grapes for both fermentation scales, sourced from the same vineyard areas and processed identically - de-stemmed, crushed by hand, and inoculated with yeast.
“This is looking at wine making in a new way - there are wineries and wine researchers who really think the only way you can do anything that’s going to be relevant to wine is at scale,” Kwasniewski said. “This study supports the idea that very small wine fermentations - just 50 milliliters or about a quarter cup - can be scientifically valid.”
Photo Credit: gettyimages-anna-tarazevich
Categories: Pennsylvania, Education