What's in my wine?

Glass of wine with a beautiful sunset as the background

It’s National Wine Day! Who knew there even was such a thing? According to National Day Calendar, this unofficial holiday is an excuse to get together with friends and family while reminiscing over a glass of wine. Perhaps you are like me—I tend to pick a bottle and pour myself a glass without putting much thought into how it was made and why it tastes the way it does.

Wine itself is made through the fermentation of grapes or other fruits, where the sugar converts into alcohol. Wild yeast from the air or commercial yeast (which is easier to control/predict the outcome of) is added to the previously crushed and pressed grapes. This yeast consumes the sugars in the fruit juice (helping to convert it to alcohol), and how much yeast is added can influence the taste of the wine. Aging the wine can also alter the flavors, with factors such as the length of aging (several years vs. several months) and the type of container used for storage (stainless steel vs. oak barrel) coming into play. Another aspect of wine’s taste, of course, is that different grapes produce different wines, and winemakers are often experimenting through different grape varietals and combinations. Obviously making wine is a complex process with many variables (these are just a few!), and the taste of the wine can change based upon a small modification to any of these many factors.

There is undoubtedly a connection between your wine's aroma and its enjoyable taste and flavor. Oftentimes when wine tasting, the wine consultant may recommend smelling your wine first before taking a sip. Drinking wine is a largely sensory experience, yet the smell of wine is also one way that the quality of wine and its flavor is monitored. Aroma profiling, or investigating the chemical analysis of the wine's aromas, provides useful information for understanding its flavor, and this can be done through gas chromatography time-of-flight mass spectrometry. GC-TOFMS has been used in a number of wine-based applications to analyze the aroma profiles of wine, uncovering such things as cork taint and over-oxidized wine, which can help with quality control and lead to an overall better tasting bottle of wine.

 

Check out our recent application work on wine aroma profiling!

Quantification of 2,4,6-trichloroanisole to Detect Cork Taint Fault in Wine with the Pegasus® BT

Cork taint is a common wine fault that leads to off-putting odors in a wine. Predicting this fault is challenging as it can occur in any naturally corked wine of any variety, vintage, price point, or geographical region. Analytically detecting cork taint is also challenging because the sensory threshold for 2,4,6-trichloroanisole (TCA), an analyte that is a large contributor to the off-odor and taste, is in the low part-per-trillion (ppt) levels for most people. In this application note, detection and quantification of TCA at levels well below the threshold are demonstrated. HS-SPME was used for sample preparation, and analysis was performed with LECO's Pegasus BT GC-TOFMS system. The Pegasus BT provides full m/z range data and sensitivity which make it ideal for screening target analytes and/or general unknowns. This robust tool makes your routine analyses easy, and has the potential to uncover what you've been missing.

Read the app note

Differentiation of Fresh and Oxidized Wine Samples with HS-SPME, GC-TOFMS, and GCxGC-TOFMS

Chemical analysis of the aromas associated with wine provides useful information for understanding a product or process. Proper storage and the impact of the introduction of oxygen to a wine sample are of interest and are explored further in this application note. Two bottles of wine, one stored properly and one that was intentionally oxidized from improper storage, were compared with headspace solid-phase micro-extraction (HS-SPME) as a sample preparation method to collect and concentrate volatile analytes from the headspace of wine samples. Chemical analysis with gas chromatography coupled to time-of-flight mass spectrometry (GC-TOFMS) and two-dimensional GC-TOFMS (GC×GC-TOFMS) were then performed. Both analytical techniques offer non-targeted and comprehensive chemical data for the samples that help you see what you are missing and characterize the samples. The extension to GC×GC with the second complementary separation dimension provides additional distinction between the samples due to the increased peak capacity and lower limit of detection. These benefits provided the ability to detect more analytes within these complex samples and uncover additional chemical differences between the storage conditions.  

Read the app note

Fresh-Oxidized_wine blog