Sensory characterisation of Cognac eaux-de-vie aged in barrels subjected to different toasting processes

Toasting is a key step in the barrel-making process. It plays an important role in the breakdown of oak wood compounds and thus influences the chemical composition and organoleptic properties of wines and brandies. However, the effect of toasting on distilled spirit quality has not yet been extensively studied. The objective of this study was therefore to study the impact of toasting on cognac eaux-de-vie by characterising the eaux-de-vie sensorially after 12 months of ageing. Eight eaux-de-vie aged in barrels with 8 different toasts were studied. The 8 toasts represented 4 different temperatures (low, medium, medium plus and high) and two toasting lengths for each temperature (one so-called “normal” and the other “slow”). Sensory analysis was carried out on these eaux-de-vie through several tests. First, a sorting test showed the differences between the samples and then training was carried out on previously chosen descriptors in order to build a sensory profile and perform a ranking test. The study was realised for two alcohol levels: 60 % (v/v), which is the alcohol level of eaux-de-vie in barrels, and 40 % (v/v), which is the alcohol level of a commercial cognac. This approach demonstrated that barrel toasting generally leads to significant sensorial differences in eaux-de-vie during ageing. These differences are greater between a lightly and a highly toasted barrel. This study is a first step in the characterisation of cognac eaux-de-vie aged in barrels made with different toasts.

SURFACE IRREGULARITIES OF OAK WOOD AFTER TRANSVERSAL CUTTING WITH A CIRCULAR SAW

This paper deals with the effect of saw blade type (24, 40 and 60 teeth) and sawn distance on the primary profile (Pz) of tranvesre surface of European oak (Quercus robur L.) after transversal cutting. Transversal cutting was provided at constant cutting speed vc = 62 m.s-1and with manual feeding using circular saw blade. An additional parameter was to determine the maximum sawn distance for each type of saw blade up to the point where the saw blade overheated, as well as the beginning of the blackening of the wood surface. The highest values of the primary profile (Pz) were achieved with a saw blade with 24 teeth, lower values were measured on wood cut with a 40 tooth blade and the lowest values after cutting with a 60 tooth blade. As the saw distance increased, there was no rapid and steep increase in the primary profile values, but these values gradually increased slightly, probably due to the gradual blunting of the tool.

The Influence of Nanoparticles on Fire Retardancy of Pedunculate Oak Wood

Traditional flame retardants often contain halogens and produce toxic gases when burned. Hence, in this study, low-cost, environmentally friendly compounds that act as fire retardants are investigated. These materials often contain nanoparticles, from which TiO2 and SiO2 are the most promising. In this work, pedunculate oak wood specimens were modified with sodium silicate (Na2SiO3, i.e., water glass) and TiO2, SiO2, and ZnO nanoparticles using the vacuum-pressure technique. Changes in the samples and fire characteristics of modified wood were studied via thermal analysis (TA), infrared spectroscopy (FTIR), and scanning electron microscopy, coupled with energy-dispersive X-ray spectroscopy (SEM-EDX). The results of TA showed the most significant wood decomposition at a temperature of 350 °C, with a non-significant influence of the nanoparticles. A dominant effect of sodium silicate was observed in the main weight-loss step, resulting in a drop in decomposition temperature within the temperature range of 36–44 °C. More intensive decomposition of wood treated with water glass and nanoparticles led to a faster release of non-combustible gases, which slowed down the combustion process. The results demonstrated that wood modifications using sodium silicate and nanoparticle systems have potentially enhanced flame retardant properties.

Biochar-Improved Growth and Physiology of Ehretia asperula under Water-Deficit Condition

Ehretia asperula’s physiological responses to growth performance following oak-wood biochar application under water stress conditions (WSC) and no water stress conditions (non-WSC) were investigated in a pot experiment. Biochar (WB) was incorporated into the soil at concentrations of 0, 5, 10, 15, and 20 tons ha−1 before transplanting Ehretia asperula in the pots. One month after transplanting, Ehretia asperula plants were put under water stress by withholding water for ten days. Water stress significantly decreased the growth and physiology of Ehretia asperula. Under WSC, the application of WB at the concentrations of 15 and 20 tons ha−1 to the soil increased the plant height; number of leaves; fresh and dry weight of the roots, shoots, and leaves; Fv/Fm; chlorophyll content; leaf relative water content; and soil moisture as well as decreased the relative ion leakage. The application of WB enhanced drought tolerance in Ehretia asperula plants by lowering the wilting point. The findings suggest that WB application at the concentration of 15 tons ha−1 could be recommended for ensuring the best physiological responses and highest growth of Ehretia asperula plants.

Late Holocene Vegetation History of Grevena Province, Northwestern Greece

<p>Palynological investigations aimed at reconstructing the vegetation history of the Grevena Province, northwestern Greece were conducted in association with an archaeological research project. Fossil pollen, spores, microscopic charcoal particles, and sediment stratigraphies of radiocarbon-dated sediment cores from three sites in pine, beech, and oak woodland zones provide evidence of climatic changes, land use, and erosion during the last 3500 years. Identification of pollen and spores was aided by an extensive reference collection of local species and construction of a pollen key modelled on that of Faegri & Iversen (1989). Extant vegetation units are characterized by their contemporary pollen assemblages. Surface samples collected along an elevational transect show that a fairly direct relationship exists between the major vegetation zones and pollen deposition: pine, beech, and oak pollen predominate in their respective zones. Over-representation of pine pollen is notable. The sequence from Gomara site in the pine wood-pasture zone at 1750 m asl covers the time span c. 1340 BC to 700 AD. A local open pine wood was gradually replaced by beech after c. 890 BC, perhaps through reduced disturbance and/or increased precipitation. A herbaceous pollen spike at c. 80 BC resulted from deposition of volcanic ash. Pine wood replaced beech at c. 330 AD. Two periods of accelerated erosion coincide with the pine wood phases and with anthropogenic burning and grazing. These periods are separated by a period of abandonment when the climate was probably wetter. The sequence from Anelia site in the beech wood zone at 1440 m asl spans c. 1560-1989 AD. The site was surrounded by beech wood for the duration of the sequence. Regional and local burning of vegetation is indicated by an abundance of microscopic charcoal particles from c. 1560 until c. 1730 AD, when it ceased. Periods of erosion occurred during this period. After c. 1730 AD a homogeneous peat formed on the wetland, suggesting a period of greater landscape stability. From pollen evidence, a variety of land-use practices such as cereal cultivation, grazing, coppicing, and lumbering were carried out in the vicinity of the site especially before c. 1730 AD, but these diminished after 1920 AD. The lower part of the sequence from Kellia site in the oak wood-steppe zone at 580 m asl is insecurely dated, but the upper part spans c. 1230-1989 AD. The lowlands were covered with deciduous/semi-evergreen oak woods for the duration of the sequence. Since c. 1230 AD land close to the site was intensively cultivated with a variety of cereals. Burning occurred frequently throughout the period. The ratio of deciduous to semi-evergreen oak pollen is correlated with temperature and indicates a decline from c. 1230-1680 AD, after which temperature increased, a pattern similar to that of the Little Ice Age. Frontispiece The cultural landscape of Grevena Province looking NE towards the Vourinos Mountains on the eastern border of Grevena, from a prominent hill about 1 1/4 km NW of the modern village of Itea. In the foreground is the stubble of a wheat field. Beyond is an 18th century church dedicated to Aghia Panaghia. The middle ground is the steppe oak wood pasture of Grevena plains. Recent erosion on the sides of gullies can be seen here, even though they appear to be well vegetated. Frescoes in the church are shown in the enlargement. It stands on a registered archaeological site, Grevena Project 108 (21 degrees 36.18' E, 40 degrees 04.29' N, 640 m asl) that covers more than 10,000 m2. Archaeological evidence dating to Early Iron Age, Archaic, Classical, Hellenistic, Roman, Early Medieval and Ottoman periods has been recorded.</p>