Maintaining good winemaking records is key to monitoring the quality of the wine. Many winemakers take good notes, recording processing steps as well as all ingredient and processing aid additions that go into the wine.
However, maintaining adequate analytical records of wine is also important.
As a consultant, I meet winemakers with a variety of experience levels and various understandings towards enology or analytical evaluation of wine. Enology is the science of winemaking. Therefore, winemakers use enology information to help guide their winemaking decisions.
Parts of winemaking are artistic. A good example of artisan part of winemaking is creating blends from numerous barreled wines. This technique is usually performed using the winemaker’s expert aroma and taste evaluation skills. However, one could argue enology could be integrated into this process, too.
While it can be underestimated, having a solid grasp on fundamental enological concepts can make winemaking easier and more efficient for most people. Having a firm understanding of basic wine chemistries, for example, can allude winemakers to a pending problem with a wine. Focusing on changes in volatile acidity (VA) at various time points of production is an example of proactively finding a potential wine problem. I describe this in more detail, below.
However, I’ve also had frequent conversations with winemakers about grape/juice titratable acidity (TA) values, the importance of yeast assimilable (available) nitrogen (YAN) prior to fermentation, residual copper concentrations, sulfur dioxide monitoring plans, and the use of microbiology assays during problem-solving periods of the winemaking process.
The point is: enology has a purpose, and every winemaker can get better at understanding key concepts in enology.
When to analyze wines and what analysis to run
Many winemakers may rely on wine analysis only when they suspect something has gone wrong with a wine.
However, having a pro-active monitoring-based wine analytical QA/QC plan is helpful, often allowing winemakers a chance to remediate issues before they become timely, expensive, or unfixable.
Winemakers do not need to know or understand the hundreds of analytical assays used to evaluate wine. In fact, most can make clear, educated winemaking decisions simply by monitoring the bare minimum wine chemistries described in the Essential Wine Production Analyses Checklist. In this checklist, analytical needs of a wine are described at various stages in production:
- At harvest and before inoculation.
- During primary fermentation.
- Post-primary fermentation.
- During malolactic fermentation (MLF).
- Post-MLF if the wine goes through MLF.
- During wine tank/barrel storage.
Monitoring certain chemical parameters at these stages can provide insight into the health of the wine. And, again, good monitoring practices are a proactive way for winemakers to find problems in a wine before a problem gets out of control.
Monitoring volatile acidity (VA) is a prime example of how being proactive is both cost-effective and educational. VA is primarily a measurement of acetic acid concentration, the main volatile acid in wine. VA is an analysis that many winemakers like to ignore, often believing they will be able to smell or taste the vinegar aroma or flavor before the acetic acid concentration becomes a problem.
However, vinegar contains about 4 – 8% acetic acid, depending on the brand and type of vinegar. This translates into a concentration of roughly 40 – 80 g/L of acetic acid.
In contrast, the legal limits of acetic acid for wine are 1.20 g/L acetic acid for white wines and 1.40 g/L acetic acid for red wines. These values are far from the 40 – 80 g/L acetic acid concentrations for vinegar. In fact, with the legal limits of acetic acid concentration well below the concentration of vinegar, elevated VAs are often missed by untrained sensory professionals, including many winemakers.
What can a winemaker do if sensory evaluation is unreliable? They can turn to analytical monitoring of VA to ensure that the acetic acid concentration remains within acceptable limits throughout the duration of the wine’s production: from harvest to bottle.
The Essential Wine Production Analyses Checklist details the timepoints in production when measuring the VA is appropriate, for example. When coupled with the Juice/Wine Analysis Recommendations Production Guide, winemakers can provide an easy reference of “what analysis to do when” during wine production and actively build an efficient and reliable QA/QC plan for their wines.
But what do the results mean?
One of the more challenging parts of wine analysis is understanding their significance. That is where the newly released Wine Analysis Expected Results Production Guide has value.
This new Production Guide includes most of the analyses discussed in the Essential Wine Production Analyses Checklist and Juice/Wine Analysis Recommendations Production Guide, detailing common results associated with each parameter for a still table wine. It also features reasons for why those results are important. For analytes like VA, more detail is provided about what the VA result should look like at different time points during production including the expected VA for a still wine after primary fermentation versus after malolactic fermentation (MLF).
Reference pH ranges for wines can provide an indication for where the wine falls in terms of whether it has a high, average, or low pH for that style (red or white) of wine. This should allude winemakers to think about what sulfur dioxide strategy (reference Sulfur Dioxide Strategies for Juice and Wine) is most appropriate for that wine. However, the Wine Analysis Expected Results Production Guide provides my general recommendations for white/rosé, red, and high pH wines as a quick reference.
All of this is to help winemakers better understand the implications of analytical results. Afterall, there is no point in measuring or monitoring a specific parameter if it has no meaning to the winemaker making decisions about the wine.
Where can you find these useful winemaking tools?
If you struggle with analytical monitoring of your wines, DG Winemaking can help. Inquire today about DGW Insider or Elite Memberships. Memberships provide you access to materials published through DG Winemaking, and an Elite Membership provides you with access to two group Q&A calls with Denise per month. These are affordable options for any winemaker to start improving their wines and planning to get in front of any potential winemaking problems. Refer to our Services page for more information.