Use Of Oak Chips Research Articles

Comparative analysis of extraction methods in distilled drinks production

The paper presents the results of studying the extraction process in the technology of distilled drinks production at the stage of their aging with the use of oak chips, which reduces the duration of the technological process and reduces technological losses. At the engineering center “FOOD ENGINEERING” of Kemerovo State University, two extraction methods were selected for studying: 1) using a batch extractor for the “solid - liquid” system with exposure to oxygen, and 2) extraction based on the effects of microwave radiation. A comparative analysis of these processing methods has shown that the method of exposure to oxygen is more effective, taking into account the increase in optical density. The degree of oak chip charring was found to affect the color of the product significantly. Microwave radiation contributes to a more intensive accumulation of polyphenols, especially while using the chips with strong charring. When exposed to oxygen, the degree of charring had little influence on the content of polyphenols; still, exposure to oxygen intensified the process of phenolic compound extraction. The content of extractive solid compounds is higher in the samples exposed to oxygen and microwave radiation compared to the control sample, with little difference between different varieties of oak chips. In this regard, it has been planned to conduct further studies of the joint effect of these intensification methods on the extraction process.

The use of oak chips during the fermentation process: effects on phenolic compounds profile and antioxidant activity in Syrah young wines

The oak chip is an alternative to the traditional barrels in winemaking in order to improve the aged quality of the red wines. This study investigated the influence of adding of oak chips during the fermentation process in phenolic compounds profile and antioxidant activity. The American (Quercus Alba) and/or French (Quercus Petreae) oak chips were added (4g L−1 doses) in the alcoholic fermentation and malolactic fermentation or solemnly in the malolactic fermentation. Results indicated that Syrah tropical wines presented higher levels (≥265,44 mg L−1) of phenolic compounds compared to wines fermented with oak chips (222,71–254,36 mg L−1). However, the wine with French oak chip added during malolactic fermentation showed a higher antioxidant activity for ORAC method. This study offers a practical application of oak chips in winemaking process as an alternative to produce quality young red wines with low cost to the wineries in places of oak barrels.

Denitrifying Woodchip Bioreactor Leachate Tannic Acid and True Color: Lab and Field Studies

HighlightsOak leached more tannic acid, true color, and chemical oxygen demand (COD) than ash and mixed hardwood chips.The factors became similar (tannic acid, COD) or below stream levels (true color) after flushing.Eleven site-years of field bioreactor data showed decreasing tannic acid and true color over time.Post-startup tannic acid was lower in bioreactor outflow than in area streams.True color did not appear to be a reliable indicator of leachate tannic acid at low concentrations.Abstract. Woodchips have been a preferred denitrifying bioreactor medium to date, but concerns about potential harmful effects of tannins in the leachate have precluded the use of oak chips in many installations. A study was conducted to compare the suitability of oak (genus Quercus) woodchips as a denitrifying bioreactor medium relative to other types of woodchips, both in lab leachate tests and in the context of observed bioreactor leaching in the field. Assessment measures included the content of tannic acid and other compounds in the leachate, as well as leachate color, which can often be high during startup. An 84-day leaching test using rectangular bioreactor cells filled with either oak (Quercus rubra), ash (Fraxinus spp. L.), or a generic hardwood blend showed that oak initially leached higher concentrations of tannic acid, true color, and chemical oxygen demand (COD) than the other two media. The significant differences in leached concentrations among the three wood types were eliminated after a finite leaching period. Tannic acid and true color in 11 site-years of field bioreactor outflow data generally decreased over time, except following a dry period when one of the bioreactors received no drainage inflow for more than two months. The lab and field results indicated the capability of woodchip bioreactors to flush at least these two analytes to ambient stream levels. True color did not appear to be the best parameter for estimating the tannin content of woodchip leachate due to discrepancies at low concentrations. Mass normalized tannic acid leaching ranged from 0.03 to approximately 40 mg tannic acid g-1 woodchip across the lab and field assessments. Oak initially leached more tannic acid, color, and COD than the other wood types, but the eventual similarity among the wood types after flushing with a sufficient number of pore volumes meant that any potentially negative environmental impacts would likely be limited to the startup period or possibly after dry periods. Oak initially eluted higher mean total nitrogen (TN) concentrations than the other wood types, but the treatments were not significantly different by day 3, indicating that biological N removal was not significantly inhibited, even with high concentrations of tannic acid. Keywords: Chemical oxygen demand, Oak, Tannin, Water quality, Wood leachate.

Effects of Oak Chip Treatments on Quality of Dry White Wines During Aging

The objective of the research was to evaluate the effect of different oak chip treatments on quality of Longyan dry white wine during aging. Phenolic substances, antioxidant activity and Cu2+ reduction force were measured. The results showed that wines treated with French oak chips (6 g/L) had significantly higher contents of total phenols (0.083 mg/mL) and flavonoids (0.063 mg/mL), also the highest total antioxidant capacity (47.853 U/mL) was observed. However the scavenging rate of DPPH free radicals and hydroxyl radical scavenging rate were the highest in samples aged with American oak chips (6 g/L) and Yanshan oak chips (2 g/L), respectively. As for 12 monomer phenols determined by high-performance liquid chromatography, French oak chips can contribute to the formation of monomer phenols, especially the generation of syringaldehyde (15.134 mg/L) and guaiacol (17.345 mg/L). Cu2+ reduction ability of wine sample increased with the increase of oak chips content. Correlation analysis revealed that the monomer phenols had a strong correlation with total antioxidant capacity, DPPH radical scavenging rate and hydroxyl radical scavenging rate. Understanding the influence of oak chips on wine properties could aid to lay a theoretical foundation for the effective use of oak chips in wine.

Исследование влияния микроволнового воздействия на процесс созревания висковых дисциллятов

Зерновое сырье является самым распространенным сырьем для производства целого ряда алкогольных напитков: водка, виски, джин, саке. Из всего многообразия алкогольных напитков виски является одним из самых популярных напитков в мире. Целью данной работы является исследование влияния микроволнового излучения на водно-спиртовой раствор в процессе созревания вискового дистиллята без потери качественных характеристик. Работа выполнена на базе Кемеровского государственного университета в лаборатории кафедры Технологическое проектирование пищевых производств. При проведении исследований использовалось классическое сырье производства напитков типа «виски» и общепринятые методики оценки экспериментальных данных. Древесная щепа является экономичной альтернативой французской или сербской дубовой бочке. Исследовательская часть проводились с использованием дубовой щепы «Сладкая ваниль» при периодическом микроволновом воздействии на обрабатываемую среду. Дубовая щепа проходит стадию обжарки в специальной печи без использования каких-либо химических веществ. Выбранный материал – французский дуб – обладает довольно большими порами, что позволяет сильно воздействовать на находящуюся в резервуаре жидкость. В процессе выполнения работы получены результаты оптической плотности, содержание полифенолов и сухих веществ в выдержанном висковом дистилляте в течение 350 дней выдержки. На заключительном этапе исследований с целью определения содержания летучих органических веществ, исследуемые выдержанные висковые дистилляты проанализированы методом хромато-масс-спектрометрии. Анализ полученных данных позволил определить рациональные параметры процесса созревания вискового дистиллята, позволяющие сократить его в 3 раза. Результаты исследований свидетельствуют об интенсификации процесса созревания вискового дистиллята, при его периодической микроволновой обработки с дубовой щепой.

Sensory profile and check-all-that-apply (cata) as tools for evaluating and characterizing syrah wines aged with oak chips.

Aging wine in oak barrels provides more complexity to the beverage, but due to the high cost of wood barrels, alternative aging methodologies such as the use of oak chips gain interest of winemakers in the new world of wines, particularly in the tropical regions. This paper reports the sensory profile and consumer perception of Syrah wine produced in the São Francisco Valley, Brazil, with the addition of American and French oak chips at different stages of the fermentation process. Higher intensity of color, coffee, woody, and sweet/caramelized aromas, sweet and woody taste were observed in the age wines as compared to a control wine (no chip addition). An affective sensory test (N = 129) revealed two segments of consumers exhibiting different attitudes to the wines: one group (N = 60) rejected all samples, whereas the other (N = 69) liked them moderately. In short, the findings provide relevant information for stakeholders in the new world of wine where oak barrels impact negatively on the cost of production of wines, as is the case in Brazil.

Measurements of the effects of wine maceration with oak chips using an electronic tongue.

The use of oak products as a cheaper alternative to expensive wood barrels was recently permitted in Europe, which led to a continuous increase in the use of oak chips and staves in winemaking. The feasibility of the potentiometric electronic tongue as a tool for monitoring the effects of wine maceration with oak chips was evaluated. Four types of commercially available oak chips subjected to different thermal treatments and washing procedures and their mixture were studied. Ethanolic extracts of the chips were analysed using electrospray mass spectrometry and 28 phenolic and furanic compounds were identified. The electronic tongue comprising 22 potentiometric chemical sensors could distinguish artificial wine solutions and Cabernet Sauvignon wine macerated with different types of oak chips, quantify total and non-flavonoid phenolic content, as well as the concentrations of added oak chips. Using measurements at two pH levels, 3.2 and 6.5, improved the accuracy of quantification.

Consumers’ knowledge of and attitudes toward the role of oak in winemaking

Oak plays an important role in the production of some white wines and most red wines. Yet, consumers’ knowledge of the use of oak in winemaking and their preference for oak-related sensory attributes remains unclear. This study examined the knowledge and attitudes of 1,015 Australian wine consumers toward the use of oak in winemaking. Consumers who indicated a liking of oak-aged wines (n=847) were segmented according to their knowledge of the role of oak in wine production. Four distinct consumer clusters were identified, with significantly different preferences for wine sensory attributes and opinions regarding the use of oak alternatives for wine maturation. One segment comprised more knowledgeable consumers, who appreciate and value traditional oak maturation regimes, for which they are willing to pay a premium price. However, a segment comprising less knowledgeable wine consumers was accepting of the use of oak chips, provided wine quality was not compromised. Winemakers can therefore justify the use of oak alternatives to achieve oak-aged wines at lower price points. The outcomes of this study can be used by winemakers to better tailor their wines to the specific needs and expectations of consumers within different segments of the market.

Evaluation of Oak Chips Treatment on Volatile Composition and Sensory Characteristics of Merlot Wine

AbstractThe effect of treatment with different oak chips on the volatile composition and sensory characteristics of Merlot wine was evaluated. Seasoned and toasted oak chips from different geographical origins and species were tested: American (Quercus alba), French (Quercus petraea) and Rumanian (Quercus robur). Differences in the lactone content, volatile phenols (eugenol and 6‐methoxyeugenol) and derivatives of vanillin were found according to the different species used. The major differences were found in wines aged with toasted chips as the concentrations of lignin derivatives increased while furan compounds appeared. The treatment with nontoasted chips increased the flavor complexity of wine due to the pleasant attributes imparted by oak wood. Rumanian chips imparted the lowest intensity of aged flavor into the wines. Meanwhile, wines treated with toasted oak chips were negatively assessed by the tasters due to the strong perception of smoke or tobacco attributes that masked the rest of the notes.Practical ApplicationsThe use of oak chips is a new alternative to barrels used in red wine aging. The oak treatments with seasoned American, French and Rumanian oak chips improved and enhanced the volatile profile of Merlot red wines. However, the chemical composition of aged wines varied in relationship to the chips use. This fact implied different sensory characteristics in the resulting Merlot wines.The toasting process is a common treatment applied to oak barrels to improve their aromatic potential. However, the toasting treatment applied to chips must be dealt carefully by winemakers. It was observed that the use of medium toasted chips produced strong intensities of smoke and tobacco impressions that masked the rest of the notes detected in aged wine. Therefore, these aspects must be taken into account by the winemakers in the choice of the type of oak chips to guarantee the success of the wine obtained.

The influence of selected oenological practices on the sensory impact of volatile phenols in red wines

<p style="text-align: justify;"><strong>Aims</strong>: Volatile phenols (4-ethylphenol and 4-ethylguaiacol) affect wine quality by imparting, above certain concentrations, aroma defects. This work aimed to evaluate the effect of some common oenological practices on the concentration of volatile phenols and the sensory impact of these odour-active compounds in wines.</p><p style="text-align: justify;"><strong>Methods and results</strong>: The studied oenological practices were based on the addition of gum arabic, mannoproteins, yeast cell walls, lees, oak chips, dairy cream and potassium caseinate and on the application of a bubbled nitrogen stream. These treatments were applied to naturally contaminated wines containing volatile phenols at concentrations above detection threshold. The treated wines were characterised by chemical and sensory analysis. The most effective treatments in the reduction of the concentration of volatile phenols were the addition of fine lees, cream and potassium caseinate. Apart from being able to partially remove these compounds (approximately 35% removal), fine lees contributed to a greater “freshness” and complexity of the wines. Although the addition of cream did decrease the sensory impact of volatile phenols, it did not benefit the wines as these were strongly marked by dairy aromas. The use of oak chips, although it did not have a notable effect on the removal of volatile phenols, led to a significant reduction in the perception of these compounds.</p><p style="text-align: justify;"><strong>Conclusions</strong>: It is demonstrated that certain oenological practices may decrease the impact of volatile phenols in red wines.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: Solutions, particularly applicable in a winemaking environment, are suggested to the wine industry.</p>

Impact of alternative technique to ageing using oak chips in alcoholic or in malolactic fermentation on volatile and sensory composition of red wines

This paper reports on a complete study of the effect of wood, in the form of oak chips, on the volatile composition and sensory characteristics of Moravia Agria wines added at different stages of the fermentation process. Aroma compounds were analyzed by gas chromatography-mass spectrometry (GC-MS). Sensory profile was evaluated by experienced wine-testers. Oak chips were added to wines in two dose rates at different stages of the winemaking process: during alcoholic fermentation (AF), during malolactic fermentation (MLF) and in young, red Moravia Agria wine. Wines fermented with oak chips during AF showed higher concentrations of the ethyl esters of straight-chain fatty acids, ethyl, hexyl, isoamyl acetates and superior alcohols than the control wines. The higher concentrations of benzene compound, oak lactones and furanic compounds were found in wines in contact with oak chips during MLF. The use of oak chips gives rise to a different sensorial profile of wines depending of the point of addition. Higher intensities of woody, coconut, vanilla and sweet spices descriptors were obtained when a large dose rate of chips was employed.

Artificial aging of Uva di Troia and Primitivo wines using oak chips inoculated with Penicillium purpurogenum

Two red wines (Primitivo and Uva di Troia) treated with oak chips inoculated with Penicillium purpurogenum were analysed in order to assess their contents of furfural, cis-β-methyl-γ-octalactone, syringol, eugenol, vanillin and 4-vinylguaiacol. Two different sizes of oak chips (small and big, of length 2 and 8 mm respectively) and two different degrees of toasting (low and high) were used in the study. Aroma compounds were analysed by gas chromatography/mass spectrometry to determine differences among samples after 15 days of chip contact time. Big oak chips inoculated with P. purpurogenum increased the level of 4-vinylguaiacol, while small oak chips inoculated with P. purpurogenum, in some conditions, increased the level of eugenol. Chip size and degree of toasting also played an important role in the content of eugenol. The use of oak chips inoculated with mould might be a promising alternative to barrel aging. Moreover, different fungal inocula could contribute to the enrichment of wine with specific compounds (e.g. 4-vinylguaiacol and eugenol).

Differences in the phenolic composition and sensory profile between red wines aged in oak barrels and wines aged with oak chips

The aim of this study was to evaluate the similarities or differences in the phenolic composition and the sensory characteristics between wines traditionally aged in new French and American barrels for different periods of time, and wines aged for 30 days with different kinds (different geographical origin al toasting degree) of oak chips. This study was carried out with two grape varieties, Mencía and Tinta del País, and in two consecutive vintages. The results obtained indicated that it was not possible to obtain wines aged with chips with sensory characteristics similar to those aged for a long time in new barrels, independently. However, the results showed that the use of oak chips could be a good alternative for elaborating young wines with slight olfactory and gustative wood notes quite similar to wines aged in new barrels for short periods of time (about three months).

The use of oak chips during the ageing of a red wine in stainless steel tanks or used barrels: effect of the contact time and size of the oak chips on aroma compounds

Background and Aims: This paper reports the influence of adding oak chips to a wine being aged either in stainless steel tanks or in used barrels on aroma compounds, comparing these wines with those aged in new barrels. Both the size of the oak chips and the length of contact time were considered. Methods and Results: Aroma compounds were analysed by gas chromatography–mass spectrometry to determine the differences in these compounds between the samples. The results showed that chips release aroma compounds into wine very rapidly, an effect that was clearly seen when they were added to the wines stored in tanks. The wines aged in new barrels continued to extract aroma compounds for a longer time, and higher concentrations were reached in these wines for most aroma compounds. Wines in used barrels with added oak chips behaved in an intermediate manner. Conclusions: Although overall quality is better in wines matured in new barrels, the use of oak chips could be considered a good choice for producing short-aged wines and for reusing used barrels under good sanitary conditions. Significance of the Study: The rapid spread of technique alternatives to oak ageing justifies studies to assess the influence of oak chips on the chemical characteristics of wines and to evaluate any differences from traditional oak ageing systems.

Study of Vanillin, Syringaldehyde and Gallic Acid Content in Oak Wood and Wine Spirit Mixtures: Influence of Heat Treatment and Chip Size

Vanillin, syringaldehyde and gallic acid are phenolic compounds which can be detected in spirits which have undergone a process of ageing in oak casks. A study has been carried out on the influence that the use of oak chips has on the aldehyde and aromatic acid content of spirits they are in contact with. These substances are to a great extent responsible for the organoleptic properties of drinks such as wine, rum, whisky and brandy, etc. This study tries to determine the influence of chip size and the time that wood must be subjected to heat treatment. It has been proved that chips particles with a diameter of 3-5 mm favour extraction processes, and that 5-6 h heat treatment allows an adequate decay of lignin, with the subsequent formation of aromatic aldehydes.

Chemical and sensory changes in white wines fermented in the presence of oak chips

Summary Three samples of French oak and one sample of American oak were analyzed by different gas chromatographic‐mass spectrometric (GC/MS) methods. Two methods of quantifying the main volatile compounds in oak wood were compared, namely, Direct Thermal Desorption coupled with GC/MS and analysis of mixtures of water‐ethanol and wines that had been in contact with oak chips by extraction using an organic solvent followed by GC/MS analysis of the extract. The ratio of the two oak lactones released into the wine by the oak chips was the same as the ratio observed in original, untreated wood. These substances are of particular sensory importance in wines aged in oak wood barrels. Thus, the use of oak chips in white wines may be advantageous. The wines steeped with the oak chips improved their acceptability rating 2 points on a scale of 9.

The use of oak chips and coconut fiber as biofilter media to remove vocs in rendering process.

The study evaluated the effectiveness of air biofiltration in rendering plants. The biofilter material comprised compost soil (40%) and peat (40%) mixed up with coconut fiber (medium A) and oak bark (medium B). During biofiltration average VOCs reduction reached 88.4% for medium A and 89.7% for medium B. A positive relationship of aldehyde reduction from material humidity (r = 0.502; α<0.05) was also noted. Other biomaterial parameters did not affect the treatment efficiency.