Oak Barrel Tannins Fingerprinted

Recently, I came across an article on my wine feed titled, "Tannins from oak barrels that flavor wine are ‘fingerprinted’ by researchers" which peaked my interest.
It's been known that wine aged in oak barrels can contribute flavors described as coconut, vanilla, spice, caramel and smoke that can affect the taste and mouthfeel of wine. Tannins also come from grape skins and which tannin, grape skins or oak wood contributed to the specific wine flavor was something that remained difficult to quantify.
Recently, scientists at Penn State developed a way to chemically characterize and identify individual tannins in wine that come from oak barrels and contribute to its flavor profile.
The word "tannin" is usually mentioned when speaking about red wines. There are two major types of tannins, hydrolysable tannins (HTs) and condensed tannins (CTs) found in foods and beverages. There are two major types of HTs, the ellagitannins (ET) and gallotannins (GT).
Why are these tannins of especial interest in winemaking?

• HTs affect both chemical stability and sensory quality
• HTs are generally exogenous to wines, primarily introduced from oak and other wood species through barrel aging or the use of oak adjuncts such as chips
• HTs compounds enhance wine antioxidant capacity, stabilize anthocyanin pigments, and contribute to mouthfeel characteristics
• HTs have been described as imparting a smooth, velvety astringency

For the above reasons, HTs are essential for understanding wine composition and maturation, and a rapid measurement method is particularly valuable for achieving quick analytical turnaround in industry settings.
However, measuring and quantifying these HTs has traditionally been time consuming, but using in-source fragmentation (ISF) instead of acid-hydrolysis (AH) generated class-specific ions directly from all HT structures and retained the chromatographic profile of the native HTs.
Realizing the advantage of using ISF, the researchers aimed to do the following:

• (1) Introduce and validate a rapid, robust in-source fragmentation (ISF) method, called hydrolysable tannin fragmentation fingerprinting (H-TFF) for quantifying ellagitannins and gallotannins, using both quadrupole time-of-flight (QTOF) and triple quadrupole mass spectrometry (QQQ) platforms
• (2) Compare conventional acid hydrolysis (AH) methods with H-TFF for quantifying HTs across both QTOF and QQQ instruments
• (3) Characterize oak chip extracts prepared in both methanol and wine matrices using the H-TFF method, enabling compound class-level tannin profiling
• (4) Integrate H-TFF with an existing condensed tannin fragmentation fingerprinting (C-TFF) method to generate a comprehensive tannin composition fingerprint across a set of oak-treated wines

To validate their method, the team used cross-platform comparisons between QTOF and QQQ and comparison to AH, using 22 red and 20 white wines. Their research involved a collaboration with Gallo, a California-based winery that provided some of the 22 red and 20 white wines analyzed in the study.

The team conducted experiments using 15 commercial oak chip products representing three types of oak used for wine-aging barrels, French oak, Hungarian oak and American oak and five toast levels.
After adding the various types of oak chips to wine samples, the researchers could then characterize the differences in hydrolysable tannins in those treated wines to determine if their method was consistent with linearity, limit of detection (LOD), accuracy, precision, and matrix interference.
The newly developed and validated H-TFF method was first applied to these 15 oak chip samples extracted in 200-proof ethanol to quantify the ET and GT in these extracts.
Red base wine (RB) and white base wine (WB) with minimal oak addition were used for calibration curve dilutions and method validation of the H-TFF.
Quantification was performed using the calibration curves prepared in a methanol-based model solution to minimize matrix effects and improve accuracy. The results revealed that, regardless of toast level, French oak contained the highest concentrations of both ellagitannins and gallotannins, followed by Hungarian oak and American oak .
In summary, the researchers found that H-TFF enables the rapid, non-destructive analysis of ellagitannins and gallotannins, offering a practical alternative to conventional AH.
References:
1. Penn State, Tannins from oak barrels that flavor wine are ‘fingerprinted’ by researcher.
2. Yanxin Lin, Bruce S. Pan, Robert (Qiang) Siu, and Misha T. Kwasniewski, "High-throughput fingerprinting of hydrolysable tannins in wine and oak wood using in-source fragmentation on QTOF and QQQ platforms", Food Chemistry, Volume 507, 1 April 2026, 148170.

Vintage 2026: Vineyard Work

If good weather prevails in March, we begin our vineyard work and this year it was very cold and snowy until the last week in March when we were able to get back into the vineyard. We began with work that we didn't get a chance to finish at the end of last year, namely lowering our nets and Velcroing the nets to our irrigation wire. We began our work in our red varieties and as of today, we've lowered 24 rows of nets and done the first pass of pruning the tops of last year's canes and making the first cut on last year's fruiting cane.
We had help from one of our friends, Ted, who came to help us with the removal of last year's canes. We have also been aided by the very nice weather that we've been having which is a change from previous years when April showers bring May flowers.
Another change we made this year was to remove our cuttings which we have stacked neatly on each linepost. So, last Thursday, Ted and our friend Mary, came to help us remove the cuttings from the vineyard. They removed all of the cuttings from 14 rows of the vineyard so we are feeling pretty good about the work that has been done so far.
There is more good weather coming up so hopefully we can get to doing the pruning that we need to do before budbreak!

2021 Rivetto Langhe Nascetta Lirano Nascetta

A few weeks ago, my husband brought out one of his recent purchases, a 2021 Rivetto Langhe Nascetta Lirano Nascetta.
It is a white wine from the Piedmont region that almost went extinct. As nebbiolo became the favored grape for wine making in Piedmont, the Nascetta, a delicate, unstable, difficult to cultivate grape with unpredictable yields, gradually disappeared from the vineyard.
The person credited with the revival of Nascetta is Elvio Cogno. In 1993 Elvio Cogno and Valter Fissore, together with other producers from Novello, accepted an unusual invitation from journalist Armando Gambera and uncorked a few bottles of Nascetta from 1986. The Nascetta astounded everyone for its fine and elegant profile, tasting very much like a Sauterne.
In 1994, not one vineyard with 100% Nascetta could be found so the grapes had to be cherry-picked from among the vineyards throughout Novello in order to make the 1994 vintage of Nascetta which consisted of 800 bottles made by Elvio Cogno.
In 2002, Nascetta became a DOC “Langhe” wine. In 2010, it obtained the most prestigious recognition of its own appellation, “Langhe Nas-cetta of the Township of Novello,” whose production is only authorized within the confines of the township of Novello and using 100% Nascetta.
The Rivetto Nascetta to me had a distinct aroma reminiscent of Viognier. The wine was mascerated on it's skin for 72 hours. I didn't really appreciate the style of this wine but I need to give it another try with an open mind if not an appreciation of being a grape rescued from near extinction.
References:
1. Azienda Agricola Cogno, The story of Nascetta, January 1, 2019.

Vintage 2026: March Pruning Time is Here

The winter was a cold and very snowy one but for the last few weeks, we have had nice enough weather to get out into the vineyard to begin our pruning duties for this vintage. We typically begin by removing all of the Agfast that we've put on the vines to keep the growing shoot straight. It's good during the growing year, but bad when we have to remove it. There are literally thousands of these little black ties in the vineyard which makes removing them a time consuming task that can take 2 weeks or so.
We thought we would try something different this year. We began by cutting the tops of last year's shoots, which have now hardened into canes. It is at this point that we remove the Agfast. My husband cuts last year's fruiting cane, leaving the few shoots that he deems will become this year's fruiting cane.

We tested our new method on our red varieties, the Cabernet Sauvignon, Cabernet Franc and the Barbera. The reds can be challenging because the tendrils are tough and difficult to remove from the trellis wire. It's a good thing to tackle this first when we are anxious to get back into the vineyard.
We have a marker in the middle of the vineyard so instead of working the entire 800 feet, we work to the marker and then work our way back. In this manner, we can do 4 half rows of the vineyard in one shift, finishing the other half of the row on our second shift.
In the one week that we've been in the vineyard, we've managed to get all of the red varieties, 6 rows, to the point of the final pruning. The method that we are using now allows us to go into the vineyard to work even if it is raining. We can remove the shoots that have been cut from the live part of the vine. This is definitely a game changer for us.
I hope that this method that we are using allows us to get the vineyard ready for bud break sooner than we've done in the past. Crossing my fingers!