The 2024 wine grape harvest began on time in August, with Napa and Dry Creek Valleys starting in the first week and Livermore's white grape harvest beginning mid-month, two weeks earlier than last year. Other regions have also reported their season starts as the weather shifts from cool to hot, putting vineyard managers in a race against the clock to avoid sunburn damage.

“With the California harvest well into picking what seems to be a beautiful harvest year, wineries are deeply into harvest preparation,” notes Eglantine Chauffour, the Director of Enology at Bucher Vaslin North America (B.V.N.A.). “By now, I’ve usually started hearing about specific challenges from our winemaker customers, but there have not been many this year beyond a few cases of sunburn. The harvest looks great, and when the vintage is perfect, as it's looking so far, we recommend a few things to optimize it.”

A good time to think about replacing sulfur

A successful vintage is the perfect time to explore alternatives to sulfur. Reducing SO₂ on grapes while protecting them from spoilage can be achieved using bio-protection. Lamothe-Abiet EXCELLENCE B-NATURE, a pure Metschnikowia pulcherrima, non-fermenting yeast, colonizes the juice early in the process, inhibiting unwanted microbes without affecting fermentation. Ideal for protecting grapes during transportation, cold soaking, maceration, and juice during transportation and settling, it protects grapes from spoilage, enhances aromatic purity, and results in wines with better color, aromatics, and a softer, rounder mouthfeel. Suitable for red, white, rosé, and sparkling wines, it's incredibly easy to use—sprinkle directly on the grapes, no rehydration needed. As 

Chauffour notes, "Our EXCELLENCE B-NATURE provides perfect microbial control with no side effects, making it a natural solution for all winemakers. I’ve worked with many winemakers on the transition, and once they try it, they love it and can stop their usage of SO2 on grapes. It is our bestseller.”

Extract the grape's full character.

Another step to optimizing grapes' potential is to focus on enhancing the wine by improving the extraction of skin compounds and increasing high-quality juice/wine yield. “In high-quality vintages, we use enzymes to extract key elements from grape skins—aromas, polysaccharides, color, tannins, and aromatic precursors,” explains Chauffour. “We recommend using a purified enzyme such as Lamothe-Abiet  OENOZYM CRUSH."

OENOZYM CRUSH is a specialized pectinase enzyme that focuses on breaking down cell walls to maximize the release of aromatic compounds, phenolic compounds, and polysaccharides, resulting in better color wines with fuller and more balanced mouthfeel and cleaner and more intense aromas. Easy to use, it can be added directly to grapes, bins, presses, or tanks. OENOZYM CRUSH also increases high-quality free-run juice or draining wine yield by 3-10%, delivering a significant return on investment and improved clarification and filtration.

Dealing with Sunburned grapes

Sunburned grapes develop thicker skin, higher protein levels, and reduced juice yields, making wines extremely sensitive to oxidation, with increased phenolics, bitterness, and spoilage microorganisms.

Chauffour recommends using bio-protection with EXCELLENCE B-NATURE to control microbial growth and an extraction enzyme like OENOZYM CRUSH to enhance juice yield and compound extraction. “Using a fining agent like Lamothe-Abiet POLYMIX NATUR’ (containing PVPP, yeast derivatives, and calcium bentonite) at pressing for whites and rosés is essential to reduce oxidation potential and bitterness,” Chauffour explains.

To counteract low aromatic intensity and overripe characteristics, boost fresh fruit aromas during fermentation with the right yeast and nutrient combinations. Chauffour advices using Lamothe-Abiet EXCELLENCE STR yeast for whites and rosés and Lamothe-Abiet EXCELLENCE DS for reds. She also recommends applying yeast mannoproteins, such as Lamothe-Abiet NATUR’SOFT, during fermentation and aging to help balance mouthfeel and structure.

“The goal is to make wines more resistant to oxidation with a balanced mouthfeel and pleasant fresh aromas, ensuring stability and ageing potential.” she adds.

To prevent premature aging, use an inactive yeast derivative rich in glutathione, like Lamothe-Abiet AROMA PROTECT, post-fermentation to improve oxidation resistance.

For more details on optimizing your vintage 2024 or managing sunburned grapes, review the protocol at this link or contact eglantine.chauffour@buchervaslin.com.