In recent years there has been a strong increase in interest in the world of barbecues and outdoor cooking in high-income countries. Referring to FAO data, an exponential growth in imports of charcoal was observed in Europe and North America. Italy is one of the major European consumers and importers. On the market it is possible to find material with different characteristics and origins. However, analysis aimed at ascertaining the quality of the material are poorly performed. This research aimed to analyze the energy properties of charcoal commonly available on the Italian market. Twenty-four bags of charcoal and charcoal briquettes were analyzed. Eighteen samples represent the products most easily found on the market, in stores and on websites. In addition, six samples were supplied directly by the producer/importing company. The samples were grouped according to the continent of origin of the material (Europe, North-Central America and South America). Charcoal briquette samples were included together in a group. Referring to the ISO 17225-1 standard, the moisture content, ash content, heating value, volatile matter and fixed carbon were determined. Except for the moisture content, the results of the tests performed on all parameters show a strong variability both between different groups and within the same group. In detail, the European charcoal samples show characteristics more suitable for their use in barbecues. These have the highest values of fixed carbon and heating value and, at the same time, low values of ash and volatile matter. On the contrary, charcoal briquettes have less suitable characteristics for barbecue. The work also highlighted some gaps in the reference standard relating to laboratory analyses. To ensure careful control of the qualitative characteristics of the products on the market, it is necessary to promote the creation of a quality brand.

The global charcoal trade is steadily growing, with high-income countries importing significant quantities of this material from regions where its production is often associated with severe environmental issues, including forest overexploitation, illegal logging, and environmental pollution. Promoting local charcoal production in high-income countries is crucial to addressing these challenges. In this study, we have chosen to focus on the European context, specifically emphasizing Italy as a case study. Our study aimed to comprehensively compare five distinct charcoal production systems, including both traditional and modern solutions, with a specific focus on evaluating the quality of the resulting charcoal. Additionally, improvements were evaluated to enhance production efficiency. Traditional systems cannot satisfy production requests, resulting in inefficiencies in manpower, costs, times, and yield. Conversely, recent innovations consider mobile and stationary kiln prototypes. Mobile kilns offer flexibility and cost savings but require operator expertise, limit automation, and have long cycles. In contrast, stationary systems operate continuously, increasing productivity and efficiency, despite higher investment costs. Notably, charcoal quality showed minimal differences. These findings highlighted the potential of new technologies to enhance efficiency, reduce cost and environmental impact, and promote sustainable charcoal production.

The growing interest in outdoor cooking has significantly increased the popularity of charcoal-based products. However, charcoal quality varies based on wood species and carbonization methods, impacting performance during grilling. Charcoal must provide consistent heat, with factors like burn duration and residue affecting cooking quality and costs. This study evaluated 23 commercial charcoal samples in Italy—15 lump charcoals and 8 briquettes. It analyzed their quality and combustion performance through proximate, physical analyses, and combustion tests on a commercial barbecue measuring weight loss, burning rate, residue, ember, and fume temperatures. Proximate analysis revealed significant heterogeneity, with some samples exhibiting moisture content (up to 11.7%), ash levels (up to 35%), and volatile matter (up to 30%) outside the recommended threshold set by EN 1860–2:2023 standard, which negatively impacted combustion efficiency. Key factors like high fixed carbon (> 75% for 10 lump charcoal samples) and heating values (> 27 MJ/kg for most lump charcoals) promoted more complete combustion with higher weight loss, burning rates, and ember/fume temperatures. Lump charcoals generally showed better combustion performance than briquettes, with higher temperatures (up to 600 °C for embers and 60 °C for fumes) and lower residues. However, briquettes exhibited a more prolonged burn duration and lower fume/ember temperatures (< 500 °C). The granulation and apparent density also influenced combustion, with smaller charcoal fractions improving burning rates. The results emphasize the significant influence of product quality and variability on combustion behavior, underscoring the necessity of rigorous production and distribution standards to ensure optimal grilling performance of charcoal-based fuels.

Cooking with charcoal is widely popular worldwide. Several types of lump charcoal and charcoal briquettes are available on the market, presenting distinct characteristics based on raw materials and production methods. Charcoal quality can significantly impact combustion properties and pollutant emissions. This study aims to: (1) assess the qualitative characteristics of commercial lump charcoal and charcoal briquettes, (2) evaluate the emission factors (EFs) associated with their combustion, and (3) investigate how different characteristics of charcoal affect air pollutant emissions. Significant differences in quality were observed among the charcoal samples analyzed. Lump charcoal generally exhibited superior characteristics, including a higher carbon content (> 75% d.b.), fixed carbon (> 75% d.b.), heating value (> 29 MJ/kg), and fuel ratio (> 4.5). In contrast, charcoal briquettes showed higher levels of volatile matter (> 20% d.b.), ash (> 15% d.b.), and moisture content (> 6% w.b.). Furthermore, charcoal briquettes exhibited higher EFs for carbon monoxide (CO) (> 250 g/kg), volatile organic compounds (VOC) (> 1.5 g/kg), and total suspended particulates (TSP) (> 7.5 g/kg) than lump charcoal. Principal component analysis (PCA) demonstrated a strong influence of qualitative characteristics on emission factors. Volatile matter, ash yield, moisture, and nitrogen content were positively correlated with higher emissions, while carbon content, fixed carbon, and fuel ratio were negatively correlated. As lump charcoal aligns more closely with the latter parameters, it releases lower emissions than briquettes. Improving charcoal production techniques and reinforcing international standards are crucial to ensure product quality, reduce emissions, and minimize environmental and health risks.

The industrial drying of tomatoes using hot air is a widespread practice. However, air drying has several issues in terms of time, energy consumption and qualitative characteristics of the final product. The study aims to improve drying through the monitoring of the tomato’s physical characteristics. The study was divided into two parts. In the first part, the kinetics of moisture, color, volume, and rehydration ratio during the drying of tomatoes were modeled according to the temperature used (50, 60, 70, and 80 °C). Moisture loss kinetics has an initial zero-order, followed by first-order kinetics once the critical moisture is exceeded. For color, a first constant trend is observed followed by a steadily increasing or decreasing variation according to the color considered (i.e., red, or brown). The use of low temperatures guarantees the least changes of physical characteristics but significantly increases the time (+ 189%). Conversely, high temperatures guarantee faster drying but cause greater tomato browning (+ 200%). During the drying, the volume decreased linearly according to the considered temperature. In the second part of the work, a tentative drying optimization was performed, based on color kinetics. A two-stage process using two temperatures was developed to reduce drying times without affecting the product quality. Also, two control tests were conducted at 50 °C and 70 °C constant temperatures. No significant quality differences were observed between tomatoes dried at 50 °C and those using the two-stage process (p < 0.05). This type of approach did not produce a qualitative deterioration of the final product and at the same time allowed a significant reduction (− 27.6%) in time.

In Italy the agricultural residues resulting from pruning of vineyards represent a potential energy resource, in particular for the Veneto region which is the second Italian region by vineyard area. This study is aimed at analyzing the main physical and chemical characteristics of vine shoots from the annual pruning of vineyards. This is for their possible use as wood chips in small-medium size power plants. International and European standards for the analysis of biofuels were used to determine the moisture content, heat value, ash content, micro and macro elemental and fibrous fraction (lignin, cellulose, hemicellulose and extractives). The samples were collected from three different vineyards in the Vicenza area. The varieties analyzed were Chardonnay, Glera and Merlot. For each variety, the three different components of vine shoots were compared: internode, node and pith, to investigate in which part of the vine shoot the greatest accumulation of metallic elements deriving from plant protection products occurs. The results show significant differences among the energy parameters of the three varieties and three vine shoot components. In particular, the pith shows low heat value and high ash content while the woody components are characterized by higher energy values. Analysis of the chemical elements showed a high content of Cu and Zn in the wood components, node and internode, causing the high ash content found. In particular, Cu content exceeds the limits set by the reference standard. As regards the analysis of the fibrous fraction, a high content of extractives was found in the pith. These extractives could be one of the explanations why the pith of the three varieties analyzed, especially in Chardonnay, have less lower heat value on dry basis (LHV0) values and high ash contents. On the contrary, the node and internode components have a higher content of cellulose, hemicellulose and lignin. Overall, the vine shoots analyzed have characteristics suitable for a possible energy use. However, due to the high ash and Cu content, according to EN ISO 17225-9:2021 standard these can only be used as wood chips for industrial purposes in large power plants.