Why do maturity monitoring on grapes ?
Grape maturity assessment is a key step for winemakers aiming to ensure the quality and style of their wines. By conducting regular analyses as harvest approaches, it becomes possible to determine the optimal picking date—maximizing aroma extraction, achieving a balanced sugar-to-acidity ratio, and supporting successful fermentations.
What is the Purpose of Maturity Monitoring in Viticulture?
The main objective of monitoring maturity on grapes is the measure its state precisely in order to:
1 – Chose the best moment to harvest based on the phenolic and technological maturity.
2 – Organise the harvest team and associated logistics
3 – Take into account the local climate (especially in Quebec/Ontario) and evaluate the vine sanitary condition.
4 – Adapt the winemaking strategy based on the grape profile.
Parameters Measured in Maturity Monitoring
Traditionally, grape maturity in the field is determined by measuring sugar levels using a refractometer. However, often times, technological maturity (sugars and acids), phenolic maturity (aromas, tannins, colour) and oenological maturity are not always well correlated. While the Brix value is important, its does not determine accurately by itself grape ripening. Testing tartaric and L-malic acids alongside sugar content will help the winemaker in his or her decision making. Maturity monitoring on grapes includes the following parameters:
Brix, Specific Gravity, pH, Titrable Acidity, Tartaric Acid, L-Malic Acid
Cross-interpretation of these parameters by a trained oenologist is important as it will provide guidance for the next steps.
Our Cool Climate Specificities
In cold climates like Quebec and Ontario, grapes may retain high levels of organic acids (mainly L-malic acid), even late into the season. During ripening, L-malic acid gradually breaks down reducing total acidity and shaping the wine’s final profile. Weather will greatly impact this degradation’s efficiency. Maturity monitoring of grapes and must analysis are therefore extremely valuable tools as they help winemakers determine whether specific oenological interventions – such as deacidification – are necessary. With accurate measurement of organic acids (tartaric and L-malic), deacidification operations can be carried out with precision and wine quality will be preserved.
When to Sample Grapes for Maturity Monitoring and How?
For a representative sample:
- -Sampling can start at the end of veraison and every week after.
- -Collect at least 200 berries at random on several rows, taking 4 berries per grape (high, low, front, back) on 50 different grapes
- -Ensure the berries are well mixed and homogenized before sending in for testing.
Find here our Sampling Guide in the “Document” tab
Why use an OEnology Laboratory for Testing ?
Testing of organic acids such as tartaric acid and L-malic acid requires specialised equipment and professional expertise. Using a profession laboratory ensures:
1 – Accurate results for tartaric and L-malic acid
2 – Clear decisions on harvest date and winemaking style
3 – Determine specific if oenology operations are needed (deacidification, fining…) before or during vinifications. Ensure good management of alcoholic and malolactic fermentation.
Key Points to Remember
1- Maturity monitoring on grapes will help determine optimal grape maturity for each wine style.
2 – Regular testing of parameters in maturity monitoring will help reduce risks linked to climate (unripe harvest) and a poor planification
3 – Working with a oenologist and a professional laboratory ensures accurate data and interpretation of results.
4 – A well managed harvest in a cool climate region helps reduce financial risks.
To Conclude...
Maturity assessments offer real value to the winemaker.
When combined with tasting and analysis, they serve as a reliable tool for determining the optimal harvest time with precision. These evaluations are also a key part of a year-round monitoring plan.
Have questions about maturity assessments, annual monitoring plans, or any other oenological topic? Feel free to contact us at 514-564-2050 or by email at info@oenoscience.com.
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