Adjusting the soluble solids of the prefermentation must is a tool by which winemakers can manipulate the flavor profile of a wine. Total soluble solids (TSS) are often modified prior to fermentation by chaptalization or the addition of water, but can be modified also in the vineyard, by allowing the fruit to further mature on the vine. This work presents the effects of harvest maturity and prefermentation

A two-year experiment investigated the effects of compost application rate on soil chemical properties, vine nutrient status, vine performance, and grape juice characteristics in a degraded vineyard soil in northern California. The intent of the research was to identify vineyard management strategies to improve soil fertility and to identify optimal compost application rates. We applied composted steer

Spotted-wing drosophila, Drosophila suzukii (Matsumura), is an invasive species to Minnesota that was first recorded in 2012. Since its arrival it has become a major pest of stone fruit and berry crops, including winegrapes. High fecundity and short generation times have allowed D. suzukii to flourish and spread throughout North America and Europe in a relatively short period of time. Laboratory and

In 2017 a survey was initiated of vineyards throughout Missouri for the presence of 19 different grapevine viruses. A total of 400 samples were collected from 25 grape cultivars, with a sample consisting of 16 petioles (four petioles from four different vines). Sampling within vineyard blocks was random, without regard to the presence or absence of symptoms. After nucleic acids were extracted from

The purpose of this study was to empirically estimate machine and labor costs for mechanization of viticultural processes and to assess the relative effect of mechanization options on viticultural costs. By identifying three external factors that determined the degree of optimal mechanization of three major viticultural processes, we developed a systematic typology of 12 unique vineyard types. To estimate

Preference host is an important factor affecting population dynamics in plant-insect interactions. In this research, the two main phylloxera genotypes found in Argentina (gB and gD) were tested on Vitis vinifera cvs. Cabernet Sauvignon, Malbec, Pedro Giménez, Chardonnay, Cereza, Criolla Grande, and rootstocks 1103 Paulsen, 101-14 Mgt, and SO4 using an excised root assay. Statistical analysis showed

The diurnal changes in vine water status and the appropriate time of day to measure leaf water potential (LWP) and stem water potential (SWP) were examined in Willamette Valley vineyards with north-south (N-S) oriented rows employing a single curtain, vertically shoot-positioned (VSP) canopy. Measurements of LWP and SWP were performed on Chardonnay and Pinot noir grapevines on seven cloudless days

Malolactic fermentation (MLF) is an important step in winemaking to improve wine quality by deacidification, increased microbial stability, and modified wine flavor. The phenolic composition of the wine influences the growth and metabolism of the lactic acid bacteria (LAB) used for MLF. Due to increased cultivation of fungus-resistant grape cultivars, the present study aimed to analyze the influence

Oak barrels are often used to flavor and color wine, beer, and distilled beverages. However, microorganisms can penetrate into the wood, making cleaning and sterilization difficult. This can lead to undesired microbial growth in the contents of the barrel during subsequent use. Information on heat penetration into barrel staves during steam treatment and associated thermal inactivation rates is scarce

The effect of additions of dried stems (DS) and whole clusters at 50% (50% WC) and 100% (100% WC) were investigated over two consecutive vintages of Pinot noir wines from the Edna Valley AVA of California (USA) at commercial scale. Addition of 100% WC led to significant increases in pH and volatile acidity. Anthocyanins, polymeric pigments, and color were more influenced by vintage than by the winemaking

The viticulture industry needs advanced grape cultivars with genes that enhance disease resistance and environmental stress tolerance to meet the challenges of a changing climate. To discover beneficial allelic variants of grape genes, we established an F1 mapping population from a cross between two North American grapevines, Vitis rupestris Scheele and Vitis riparia Michx. We generated genotyping-by-sequencing

Economic pressures in the New York Concord grape industry over the past 30 years have driven crop management practices toward less severe pruning to achieve larger crops. The purpose of this study was to investigate the effect of crop load on juice soluble solids and the seasonal change in vine pruning weight in New York Concord grapevines. Over a four-year period, vines were balanced pruned at two

Currently, growers and winemakers of cold climate interspecific hybrid grape (CCIHG) cultivars rely solely on the technological maturity variables Brix, titratable acidity (TA), and pH as ripening indicators for harvest and winemaking decisions. In contrast, using additional chemical variables to determine optimal harvest times is a common practice in most regions of the world where the European grape

Grapevine winter hardiness is governed by several factors besides extreme weather conditions, such as site-specific soil factors (texture, composition, moisture, drainage), vine water status, and yield. It was hypothesized that winter hardiness would be influenced by specific vineyard terroir-driven factors and that zones in vineyards with low water status (leaf water potential [Ψ]) would likewise

The effects of grapevine red blotch disease (GRBD) on vine performance were studied in a Cabernet franc vineyard in the Okanagan Valley, British Columbia, over two years. Vines with GRBD had lower pruning mass, were less winter hardy than non-GRBD vines, and produced lower yields comprising fewer clusters and larger berries with more seeds. GRBD reduced photosynthesis and stomatal conductance for asymptomatic

The economic losses due to grapevine leafroll-associated virus 3 (GLRaV-3) are substantial and vary significantly across California grape regions. We expand a published economic model designed to estimate the losses associated with GLRaV-3 to accommodate the varied production and market conditions that prevail across these regions. This expanded model provides the basis for assessing the value of screening

Pinot noir fruit is often relatively low in the phenolics important for wine mouthfeel and color stabilization. Previous research has shown that leaf removal can influence the concentration and composition of Pinot noir fruit phenolics, but it is not clear to what extent these effects on grape composition are carried through the winemaking process. A novel thermal treatment, Controlled Phenolic Release

This study investigated the effect of select non-Saccharomyces yeast strains on Hanseniaspora uvarum growth and acetic acid and ethyl acetate production during prefermentation cold soak. We tested commercially available non-Saccharomyces yeasts for their ability to reduce H. uvarum growth and acetic acid production during a simulated cold soak in a grape juice-based medium. All tested non-Saccharomyces

New barrels (16 L) differing by oak species (Quercus alba or Q. petraea) and toasting level (light or heavy) were infected with Brettanomyces bruxellensis. Infected staves were sawed into 3 cm × 3 cm cubes and immersed 2 mm into red wine (11 or 15% v/v alcohol) that had been heated to 35, 40, 45, or 50°C. After removal from the wine, cubes were either sawed into cross sections or prepared as oak shavings

A set of 178 grape accessions collected in Emilia Romagna, from widely cultivated to nearly extinct and thus maintained in ex situ regional repositories, were analyzed at 10 microsatellite (Simple Sequence Repeat [SSR]) markers for correct identification. Ampelographic and local historic data were also gathered. Varietal identity was established through comparison with reference SSR profiles, often

Recent work has evaluated the kinetics of free and total sulfur dioxide (SO2) loss in wine following aerial exposure, but little work exists on the relationship between free and total SO2 during the oxidation conditions expected during wine storage. We report changes in free and total SO2 in three wines (Chardonnay, Merlot, and Cabernet Sauvignon) stored for up to 400 days at 19 or 31°C in different

Conventional methods such as Ripper titration and aeration-oxidation (A-O) are widely used for the analysis of sulfur dioxide (SO2) in wine. However, the free SO2 reported by these procedures is overestimated due to dissociation of weakly bound SO2 forms during the analysis, particularly from anthocyanin-bisulfite complexes. “Truly” free SO2 in wine can be determined from the headspace SO2 concentration

Weather data from the Prosecco area were used to apply a proposed model for estimating δ18O values in wine (HV; Hermann and Voerkelius 2008) and to determine the spatio-temporal variability of these values. Eleven reference stations provided meteorological data from 1973 to 2017. The model revealed interannual and spatial variability similar to that observed for other grape varieties or viticultural

Accurate information regarding crop reproductive development and yield formation in response to water deficits is needed for informed vineyard irrigation management decisions, particularly when water supply is limiting. Fifteen red winegrape cultivars grown in the San Joaquin Valley of California were subjected to two regulated deficit irrigation (RDI) treatments for four years to determine yield component

Saccharomyces cerevisiae is usually the dominant yeast in winemaking. However, other yeast species such as Saccharomyces uvarum are also able to conduct and complete alcoholic fermentation. S. uvarum is a cryotolerant yeast that has been found dominating low-temperature fermentations at commercial wineries around the world, but little research has been conducted to investigate its competitive abilities

Simultaneous inoculation of yeast and lactic acid bacteria (LAB) is considered a state-of-the-art strategy to reduce overall vinification time and improve microbiological stability of wines. This inoculation protocol sparked interest in selecting yeast and LAB strains to modulate malic acid consumption rate and wine composition. The study presented here addresses the impact on malic acid consumption

The three-cornered alfalfa hopper, Spissistilus festinus (Say) (Hemiptera: Membracidae) was identified as a vector of grapevine red blotch virus (GRBV) in a greenhouse study. GRBV impacts berry maturation, resulting in reduced accumulation of total soluble solids, increased titratable acidity, and altered levels of secondary metabolites that affect color, flavor, and aroma of finished wine made from

Most viticultural regions in the world annually sustain spring frost injury-associated yield loss. Researchers have developed sprayable products to prevent spring frost injury by delaying budbreak. The goal of this research was to evaluate the efficacy of novel products, including Amigo oil,® ProTone,® and FrostShield,® to delay budbreak and the effect of these products on vegetative and reproductive

Mycotoxins are toxic metabolites produced by various genera of fungi. Fungi belonging to species of the genera Aspergillus and Penicillium are the main source of ochratoxin A (OTA) in wine. The reduction of OTA in must and wine has been studied using physical, chemical, and biological technologies. In this paper, we report on the capacity of different cultures isolated from Tempranillo winegrapes contaminated

A large-scale sampling plan was performed over four years in three different vineyards to evaluate the occurrence of wine-related yeast species in the soils underneath both vines and forest oak and fruit trees close to the vineyards. Ascomycetous fermentative yeasts were present in 27% of 320 soil samples throughout the sampling years, with incidences that could not be related to sampling season. The

Grapevine water status of Vitis vinifera cvs. Riesling, Cabernet franc, and Pinot noir was evaluated in Ontario, Canada, using leaf water potential (Ψ) and surface soil water content (SSWC; %) to examine spatial relationships between soil and vine water status and berry composition variables, particularly secondary metabolites. The goal was to assess their significance as drivers of the terroir effect

The effects of temperature and concentrations of ethanol and anthocyanin on the adsorption and desorption processes of anthocyanin onto cell wall material were investigated. Independent variables included temperatures of 15 and 30°C, model wines with ethanol concentrations of 0 and 15%, and anthocyanin concentrations of 1, 1.5, and 2 g/L. These experiments were conducted in triplicate in bench-top

Proximal sensing technology was developed to overcome many of the restrictions related to satellite- or aircraft-based remote sensing systems. Ground-based proximal sensing systems collect multispectral images in the visible and near-infrared wavebands and calculate vegetation indices, such as the normalized difference vegetation index (NDVI). The objective of this study was to assess the usefulness

Wine color is an important sensory attribute originating from anthocyanins present in grape skin. The present study investigated the involvement or interference of bacterial cells (Oenococcus oeni and Lactobacillus plantarum mixed culture) on the adsorption of Shiraz anthocyanins during co-inoculation with yeast. The yeast-bacterial interactions during co-malolactic fermentation resulted in higher

Grapes are consumed throughout the world in different ways, ranging from fresh fruit to processed products. Regardless of the product, risk management starts in preharvest stages to control initial development of mycotoxigenic fungi and avoid consequent problems in the whole chain. The main concern in grapes and grape products is the presence of black Aspergillus species and the subsequent production

Winemakers often add exogenous products to increase the tannin content in red hybrid wines, but the recommended dosage of 50 to 400 mg/L may not increase the final concentration of condensed tannins effectively. In 2013, wines were made from Maréchal Foch, Corot noir, and Cabernet franc to compare retention of exogenous tannins in interspecific hybrids and Vitis vinifera. After analyzing 12 commercial

Removal of basal leaves early in the vegetative and reproductive development of grapevines is a tool used to decrease fruit set, lower cluster rot severity, and improve fruit quality. However, the considerable time required for implementation limits its use by grapegrowers. Efficient mechanization can potentially mitigate these issues, albeit this practice has not yet been compared to manual application

The potassium (K) requirements of Pinot noir grapevines were studied in a microplot vineyard, where four levels of fertilizer K supply were carefully controlled. Vine nutrient status, productivity, and must chemistry were studied over four years, and fermentation dynamics were evaluated over three years. Vine productivity, based on leaf area, pruning weights, and yield, was reduced by K supply only

To gain a better understanding of environmental effects on grapevines and the physiological regulation of acclimation, we determined the effects of soil temperature (14 or 24°C) between anthesis and veraison on growth, nonstructural carbohydrates, cytokinins, abscisic acid, and leaf function of potted Vitis vinifera cv. Shiraz. Plants of each regime were selected from two groups that had been grown

Understanding of phenolic extraction during fermentation has long been limited to either empirical studies or well-mixed models, which limits the ability to predict the impact of winemaking decisions on final wine phenolic profile. We have developed a combined phenolic extraction and fermentation model that accounts for the heterogeneous nature of red wine fermentations and fermentor geometry by combining

A precise count of flower number per inflorescence is essential to characterize the reproductive behavior of a vine. Previous efforts to automatize this process by image-based technologies have failed in the development of a universal system that can be applied to multiple grapevine cultivars, or they have been tested in a set of inflorescences of narrow morphological diversity. Here, we have developed

The development in young white wines of 2-aminoacetophenone, commonly known as atypical aging defect (UTA), leads to unpleasant notes such as mothball, wet mop, sweaty, acacia blossom, or soap. Tryptophan and indole-3-acetic acid, the most abundant auxin in plants, are considered to be the primary precursors of this compound. Indole-3-acetonitrile; indole-3-lactic acid; skatole; tryptophol and the

Wild Vitis spp. and their interspecific hybrids are known to have high malate concentrations at sugar maturity as compared to domesticated Vitis vinifera, but it is unknown if differences in malate at harvest among species arise from differences in malate accumulation or degradation. Over two years, fruit from Vitis riparia and Vitis cinerea accessions along with commercial V. vinifera and interspecific

Brettanomyces bruxellensis is a spoilage yeast particularly dreaded in red wines, where it produces volatile phenols with sensory properties that lead to wine spoilage. The development of this yeast often occurs during wine aging, especially during the summer. We show that in the Bordeaux region, the temperatures of some cellars rise significantly in July, August, and September. This greatly increases

Wines produced from red interspecific hybrid grape cultivars (Vitis spp.) typically have lower tannin concentrations than wines produced from vinifera cultivars, which can be attributed to the lower concentration of tannins and higher concentration of tannin-binding proteins of interspecific cultivars. Tannin in wines produced from hybrid cultivars may be increased by blending hybrids with vinifera

Simón de Rojas Clemente y Rubio (1777 to 1827) is considered the father of modern ampelography. He developed the first scientific method for describing grapevine varieties through the examination of material he collected in Andalusia between 1802 and 1804. The Royal Botanical Garden in Madrid conserves the material he collected and preserved (leaves and shoots). This herbarium, the oldest of all grapevine

Severe prebloom leaf removal dramatically affects the source-sink balance in grapevines, leading to a reduction in fruit set. In this study, carried on for two consecutive years, the impact of defoliation at bloom was evaluated with the objective to assess the capacity of developing inflorescences to attract photosynthates from adjacent shoots subjected to varying source/sink manipulations. In Pinot

Fermented beverages are frequently contaminated with histamine produced by lactic acid bacteria exhibiting histidine decarboxylase activity. In wine, the presence of histamine is associated with a lack of hygiene during the winemaking process. Determination of histamine is important because it can be toxic to humans. Therefore, we developed two rapid, inexpensive, and simple methods—a colorimetric

The rise in air temperature due to climate change is causing an increase in the sugar accumulation rate in grape berries, resulting in increased wine alcohol concentrations. Postveraison leaf area removal (defoliation, shoot-trimming) is a suitable canopy management strategy to slow carbohydrate accumulation in the berries. However, in late-ripening cultivars, the phenological stage between veraison

When grapes are exposed to wildfire smoke, several smoke-related aroma compounds can be transferred to the berries and become glycosylated. Although the compounds do not contribute to grape aroma in the glycosylated form, the free volatile phenols can be released throughout winemaking and wine aging to produce undesirable “smoke tainted” wines. Measurement of the intact glycosides provides insight

Canopy management techniques can be beneficial to grapevine reproduction because they improve canopy structure and microclimate. In this study, the influence of different canopy management practices—cluster thinning, leaf removal, shoot-thinning, and light pruning—on reproductive performance was studied for the varieties Semillon and Shiraz grown under field conditions in a hot climate in South Australia

Yeast inoculation from the tops of tanks is common in white wine fermentations. Our objective was to examine whether inhomogeneities occur in tanks following yeast addition from the top with and without brief stirring after inoculation. We investigated whether inhomogeneities affect fermentation kinetics and formation of acetaldehyde, acetic acid, and pyruvate in Riesling juices with low turbidity

The objective of this study was to compare the effect of sustained deficit irrigation and regulated deficit irrigation strategies on the yield components and berry composition of two winegrape cultivars (Vitis vinifera L.) that differ in their hydraulic behavior. Malbec and Syrah grapevines were grown in southern Idaho under arid conditions and were drip-irrigated weekly from fruit set until harvest

Grapegrowing areas worldwide are experiencing earlier and compressed phenology because of higher temperatures, which has led to excessive sugar accumulation in grapes. This is associated with negative effects on grape and wine quality and higher alcohol in wines. Recent research has shown that early, climate-related ripening can be ameliorated by late leaf removal above the cluster zone. This practice

Microsatellite markers are a valuable tool to facilitate the management of germplasm collections and assess genetic diversity. This study reports the genetic characterization of a large collection of 379 rootstocks and other non-vinifera accessions maintained at the University of Milan, Italy. Accessions were genotyped with 22 highly polymorphic microsatellite markers, including the nine “international”

This article synthetizes observations from five experiments and reports on the effects of timing and intensity of defoliation on the white and red Vitis vinifera cultivars Pinot noir, Gamay, Merlot, Chasselas, and Doral. Intensive defoliation (removal of six basal leaves + six lateral shoots per shoot) was completed at three developmental stages of the grapevine: preflowering, flowering, and bunch

The introduction of cold climate interspecific hybrid grape (CCIHG) cultivars has stimulated a new wine industry in northern climates; however, high fruit acidity at harvest and limited information on fruit composition of these new cultivars make producing quality wines difficult. Organic acid and sugar profiles were determined during two growing seasons for Brianna, Frontenac, La Crescent, and Marquette

Microoxygenation (MOx) is used to reduce vegetal aroma and improve color by converting anthocyanins to stable pigments. A Cabernet Sauvignon wine treated with different levels of sulfur dioxide (SO2) and glutathione (GSH) was microoxygenated, bottled with equivalent free SO2 levels, and stored under controlled conditions for 28 months. After bottle aging, the MOx-treated wines, particularly those treated

This study investigated the influence of nitrogen content on both β-glucosidase and β-xylosidase activities from non-Saccharomyces yeasts. Enzymatic activities were induced by the presence of xylan polysaccharides in the medium. Results show that optimizing β-glucosidase and β-xylosidase enzymatic activities can be determined not only by sugar or ethanol content or pH, but also by the concentration

A traditional crop load regulation technique, cluster thinning (CT), was compared to a more innovative technique, early leaf removal (ELR) applied either at trace bloom (TBLR) or fruit set (FSLR), on high-yielding and vigorous Vitis vinifera cv. Grüner Veltliner. Treatment effects on key production parameters, Botrytis bunch rot, tolerance to winter temperatures, and production costs were evaluated