Testing phenolic maturity for smooth structured wines

10. mai, 2017
Tracking the phenolic maturity of grapes is helping Union de Producteurs in St. Emilion to make better wine with a significant increase in the volume of grapes going into top cuvee wines over recent years.

Union de Producteurs (UdP) has made good use of the FOSS WineScan™ for fast phenolic maturity analysis for managing harvests for more than ten consecutive years through a programme led by Betrand Bourdil, technical director at UdP.

Bourdil explains: “We had a vision to use phenolic maturity analysis as a central element in the management of harvest planning and to encourage the grape growers to deliver the best possible grape material for the winemaking. With insight to grapes’ phenolic maturity, our vision was to be able to plan the vinification optimally.” 

Bertrand Boudil

Betrand Bourdil (left) explains the phenolic programme 

How it works
As grapes approach maturity, samples are collected from the growers and measurements are made on WineScan for sugar content, total acidity, malic acid, total polyphenol, and anthocyanins (Glories ApH 1, ApH 3.2 and seeds maturity).

Each geographic plot is measured a minimum of three times during three weeks before the harvest. The results enable UdP to consult with the grape growers on optimal harvest time to obtain the best phenolic maturity and strategies for improving grape quality. The harvest time and winery opening can thereby be predicted and planned in an early stage. The harvest date is typically fixed between 18 and 22 days after the end of berry growth.

The sample preparation is critical for measuring phenolic maturity. The protocol for crushing, skin extraction and filtering the 400 berries-sample must be followed strictly to ensure that the WineScan Glorie calibrations work well. UdP’s capacity is around 200 samples per day.

Payment parameter
Today, the payment for grapes depends on advanced quality analysis, including physiologic as well as phenolic maturity and soundness quality, all of which are measured at reception on the WineScan.

“Over the years, we have implemented and refined a payment system so our grape growers have a strong financial incitement to deliver the best possible grapes. For example, the more anthocyanins the grapes contains, the higher payment. And we have clearly been able to turn the better grape material into better wines with more structure,” says Bourdil.

By keeping a close eye on anthocyanin development in the grapes, UpD can track the maturity of grapes and decide the most appropriate vinification path. “We have the possibility of making up tanks depending on phenolic richness and maturity data of the grapes,” says Bourdil. “Glories level gives the grape potential when tanks are filled in. The more concentrated the grapes are, the better the potential. We can decide the degree of bleeding, post fermenting maceration and extraction strategies.” Since 2005, UpD has managed to increase the grape volume that goes into top cuvee wines from 8% to 25%. 

Saint Emilion Logo


Union de Producteurs 
Union de Producteurs (UdP) is the largest cooperative in St. Emilion, Bordeaux, France with a grape intake from more than 700 hectares corresponding to approx. 15 % of the St. Emilion appellation. The grapes are supplied to UdP by 150 growers. UdP has a unique winery facility where no pumps and pipes are used for the 400 fermentation tanks. A crane system ensures that tanks are moved instead of the wine.  The grapes from each Chateau are vinified separately in unique tanks to ensure the authenticity of each wine.

See more industry-related articles and videos

Voir plus

back to top icon
The content is hosted on (Third Party). By showing the content you accept the use of Marketing Cookies on You can change the settings anytime. To learn more, visit our Cookie Policy.