Cold Brew Research Articles

Extraction and physicochemical characteristics of high pressure-assisted cold brew coffee

This research used ultra-fast E-nose, E-tongue and SCA analysis to explore the effects of different sterilization methods (pasteurization, back pressure sterilization, high temperature short-term sterilization, membrane filtration treatment and high pressure processing) on cold brew coffee. The results showed that non-heat sterilization can better maintain the sensory quality of coffee liquid. Back pressure sterilization could reduce the pH value of coffee liquid to 4.65, and decrease the aroma content significantly by 50.5% (<i>p</i> &lt; 0.05), while the sourness and bitterness of coffee samples increased, which lowered the sensory quality of coffee. Among the heat sterilization treatments, high temperature short-term sterilization had relatively little effect on the sensory quality of the coffee beverage, and decreased the bitterness of the coffee. Taking sensory quality, nutrients and cost into consideration, it is suggested that high temperature short time sterilization is a prefered method. Thus, the results of this research provided a theoretical basis for the selection of sterilization method for cold brew coffee.

Pilot-scale generation of plasma processed air and its influence on microbial count, microbial diversity, and selected quality parameters of dried herbs

Kopi adalah salah satu minuman yang paling banyak didistribusikan dan dikonsumsi di dunia. Kopi umumnya diseduh dengan air panas, namun seiring dengan berkembangnya industri kopi, proses penyeduhan kopi juga bisa menggunakan air dingin. Teknik seduhan tersebut disebut cold brew . Informasi mengenai karakteristik cold brew masih sedikit, sehingga perlu dilakukan studi terkait karakteristik minuman cold brew khususnya dengan kopi lokal Indonesia. Penelitian ini menggunakan kopi Arabika Menoreh sebagai obyek utama penelitian. Tujuan penelitian ini adalah untuk mengetahui karakteristik fisikokimia dan sensoris kopi Arabika Menoreh dengan teknik seduhan cold brew . Penelitian diawali dengan penyangraian kopi menjadi tiga jenis yaitu light (T = 193 o C, t = 5 menit), medium (T = 208 o C, t = 7 menit), dan dark (T = 223 o C, t = 13 menit). Selanjutnya, kopi digiling menjadi dua jenis ukuran gilingan ( medium dan coarse ) . Pembuatan sampel formulasi minuman cold brew dilakukan dengan waktu ekstraksi 8 jam. Analisis sensoris dilakukan berdasarkan metode SCA. Analisis data sensoris dilakukan untuk menentukan tiga formulasi terbaik sesuai profil sangrai, kemudian dilanjutkan dengan analisis fisikokimia. Sampel cold brew terbaik yang diperoleh dari penelitian ini adalah kopi Arabika Menoreh medium - coarse dengan nilai parameter sensoris tertinggi yaitu aroma, acidity, aftertaste, dan sweetness . Nilai pH, asam klorogenat, dan beberapa asam organik berpengaruh terhadap asiditas (keasaman). Asam laktat berpengaruh terhadap nilai bod y dan kadar kafein relatif stabil pada masing-masing sampel. Hasil penelitian ini dapat dijadikan sebagai acuan diversifikasi produk kopi Arabika Menoreh.

Cold brewing coffee has gained increasing popularity as a novel brewing method. A completely different flavour profile during cold brewing extraction (smooth and mild) is a result of the low-energy process, prolonged water-grind contact times and long preparation time. The aim of our research was to compare coffee drinks obtained with an innovative device for a faster, dynamic cold coffee extraction process (Hardtank) to drinks prepared traditionally in 24 h and hot brewed drinks. This study investigated the differences in chemical composition (volatile, non-volatile and lipid compounds), sensory properties and antioxidant capacity of coffee drinks from various extraction processes carried out at variable brewing temperatures, times and percolation modes. The results showed that the new cold maceration technique using coffee bed percolation (Hardtank) improved the quality of cold coffee drinks, making them similar in taste to hot coffee drinks. Among the studied extractions, the combination of a lower temperature (19.3 °C) and percolation process appeared to be the ideal setting for the most efficient extraction of compounds such as chlorogenic acids, gallic acid, caffeine, trigonelline, 5-(hydroxymethyl)furfural and lipids and consequently for their intake. In addition, FTIR spectra indicated an even 4 times greater quantity of lipids in Hardtank drinks than in classic cold brew and up to 5 times more lipids than in hot brew coffee, which contribute to the formation of the aroma and flavour. The decreased extraction time and use of coffee bed percolation could be beneficial for the quality and taste of cold brew products.

The valorisation of ground coffee beans is discussed in two parts; the first research question relates to the extraction of cold brew from ground coffee beans to provide a healthy cold beverage. Two parameters were investigated: temperature, and the ratio of ground coffee beans to water. This work suggests that cold brew coffee can be extracted between 15 and 20 °C over 2 to 4 h instead of 24 h as outlined in typical cold brew extraction processes. The coffee aroma was the response variable. Part of this investigation was to develop a downstream product from the waste spent grounded coffee bean. This part of the study investigates the production of firelighters from spent ground coffee beans to reduce the impact of dumping significant quantities of spent coffee grounds from coffee houses, restaurants, and baristas on landfill sites, which can lead to environmental problems such as polluting water systems, killing wildlife and disturbing ecosystems. The study used spent ground coffee beans in products such as firelighters to test their efficacy. This application has shown promising results, with the firelighters showing longer burning times for the ignition of log fires while also emitting a gentle, pleasant coffee aroma.

The Covid-19 pandemic has an impact on coffee consumer behavior, especially consumers who make purchases at coffee shops. This study aims to determine the motivation of consumers to buy coffee and identify the decision-making process of consumers buying coffee at coffee shops in Padang City during a pandemic. The method used is a survey method on 100 consumers in 10 coffee shops (Coffee Shops Janji Jiwa, Rasa Coffee, Kopi dari Hari, Kupi Batigo, Rimbun Espresso &amp; Brew Bar, Kubik Koffie, Bacarito Kopi, Dua Pintu Coffee, Lalito Coffee Bar, V Coffee) in Padang City. These variables are the motivation to buy and stage of the consumer decision proses (need recognition, Information Search, evaluation of alternatives, purchase decision and post-purchase evaluasion). Data were analyzed using descriptive statistics from the frequency distribution table. The results showed that the motivation of consumers to buy coffee in coffee shops was due to the comfortable atmosphere, eliminating boredom and the taste of coffee with the most purchased types of coffee, namely espresso based lattes (47%) and manual brew cold brew. (29%). In the process of making purchasing decisions at the need recognition stage, the benefit that consumers want to seek is good taste (60%). At the information search stage, most coffee purchases are based on information from friends (63%) and social media influence (67%). The alternative evaluation stage, consumers choose the comfort of the place (53%). At the stage of the purchasing process, consumers choose a good taste of the product, a comfortable place with attention to health regulations. The post-purchase stage is mostly satisfied with the coffee purchased and 92% of respondents will buy again

Support for food innovation

Monitoring of Microbial Contamination and Caffeine Content of Cold Brew Coffee

Analysis of α-dicarbonyl compounds and 4-methylimidazole in coffee made with various roasting and brewing conditions

SummaryEffects of ultrasound combined with high hydrostatic pressure (HHP) on physicochemical properties,microorganisms and storage attributes of cold brew tea were investigated. HHP at 400 MPa/5 min/25 °C inactivated the total aerobic bacteria, yeast and mould in cold brewed tea prepared by static brewing (SB‐tea) at 13 h/4 °C, ultrasonic bath (UB‐tea) at 150 W/120 min/0 °C and ultrasonic pulveriser (UP‐tea) at 600 W/40 min/0 °C, ensuring their microbiological safety. The results showed that there was no significant difference in the concentration of tea polyphenols between hot brewed tea prepared by 7 min/100 °C and cold brewed tea under different preparation conditions, while the caffeine in cold brewed tea was significantly lower (P &lt; 0.05) than that in hot brewed tea. During the storage period of 8 days, compared with the untreated group, the cold brewed tea after HHP treatment had better microbiological safety. In addition, HHP treatment constantly maintained the tea polyphenols, pH, colour, antioxidant capacity and turbidity in cold brewed tea. The untreated and HHP‐treated cold brew tea were evaluated by 20 trained volunteers. Results showed that UB‐tea was more close to SB‐tea than UP‐tea in sensory profile, while HHP seem to maintain a good sensory profile as well. Therefore, this particular combined technology of ultrasonic bath and HHP displayed considerable potential for application in the cold brew tea manufacturing industry.

Coffee is one of the most often consumed beverages almost all over the world. The multiplicity of beans, as well as the methods and parameters used to brew, encourages the optimization of the brewing process. The study aimed to analyze the effect of roasting beans, the brewing technique, and its parameters (time and water temperature) on antioxidant activity (determined using several in vitro methods), total polyphenols, flavonoids, and caffeine content. The infusions of unroasted and roasted Arabica beans from Brazil, Colombia, India, Peru, and Rwanda were analyzed. In general, infusions prepared from roasted beans had higher antioxidant activity and the content of above-mentioned compounds. The hot brew method was used to obtain infusions with a higher antioxidant activity, while the cold brew with higher caffeine content. The phenolic compound content in infusions prepared using both techniques depended on the roasting process. Moreover, the bean’s origin, roasting process, and brewing technique had a significant effect on the tested properties, in contrary to brewing time and water temperature (below and above 90 °C), which had less impact. The results confirm the importance of coffee brewing optimization.

Volatile compounds of coffee brewed under various roasting conditions and by different brewing methods were analyzed. Green coffee beans (Coffea arabica) were roasted at 235 °C for 13 min, 240 °C for 15 min, and 245 °C for 17 min. Roasted coffee beans were ground into particles of three different sizes (710, 500, and 355 μm) and brewed by an espresso coffee machine and the cold brew method. Three types of water (filtered, tap, and bottled) were used for coffee extraction. SPME-GC-MS results indicated that increasing the roasting temperature and time increased the levels of 2,2′-methylene-bis-furan, guaiacol, and 4-ethylguaiacol (p < 0.05) and decreased the levels of furfural (p < 0.05). Grind size was inversely proportional to the measured signal of volatiles by GC-MS (p < 0.05). The measured GC/MS intensities of 2-methylpyrazine, 2,5-dimethylpyrazine, and 2-methoxy-4-vinylphenol were significantly higher in coffee brewed with filtered water (p < 0.05) than tap and bottled water. 2-Methylpyrazine, 1-methylpyrrole, and 2-acetylfuran were the most abundant components in the cold brew. Overall, roasting conditions and extraction methods were determined to be significant factors for volatile compounds in coffee. This is the first study showing the analysis of volatile compounds in coffee according to various types of water and extraction methods, such as espresso and cold brew coffee.

Cold brew coffee is a new trend in the coffee industry. This paper presents pilot studies on several aspects of this beverage. Using an online survey, the current practices of cold brew coffee preparation were investigated, identifying a rather large variability with a preference for extraction of medium roasted Arabica coffee using 50–100 g/L at 8 °C for about 1 day. Sensory testing using ranking and triangle tests showed that cold brew may be preferred over iced coffee (cooled down hot extracted coffee). Extraction experiments under different conditions combined with nuclear magnetic resonance (NMR) analysis showed that the usual extraction time may be longer than necessary as most compounds are extracted within only a few hours, while increasing turbulence (e.g., using ultrasonication) and temperature may additionally increase the speed of extraction. NMR analysis also revealed a possible chemical differentiation between cold brew and hot brew using multivariate data analysis. Decreased extraction time and reduced storage times could be beneficial for cold brew product quality as microbiological analysis of commercial samples detected samples with spoilage organisms and contamination with Bacillus cereus.

Specialty and regular coffee bean quality for cold and hot brewing: Evaluation of sensory profile and physicochemical characteristics

Draw Comparison of Chlorogenic Acid Content According to Cold Brew Water Coffee Extraction Conditions

Brewing conditions impact on the composition and characteristics of cold brew Arabica and Robusta coffee beverages

Effects of different stabilization techniques on the shelf life of cold brew coffee: Chemical composition, flavor profile and microbiological analysis

Chemical and sensory evaluation of cold brew coffees using different roasting profiles and brewing methods

It is well known that the appearance of food, particularly its color, can influence flavor perception and identification. However, food studies involving the manipulation of product color face inevitable limitations, from extrinsic flavors introduced by food coloring to the cost in development time and resources in order to produce different product variants. One solution lies in modern virtual reality (VR) technology, which has become increasingly accessible, sophisticated, and widespread over the past years. In the present study, we investigated whether making a coffee look milkier in a VR environment can alter its perceived flavor and liking. Thirty-two United Kingdom (UK) consumers were given four samples of black cold brew coffee at 4 and 8% sucrose concentration. They wore VR headsets throughout the study and viewed the same coffee in a virtual setting. The color of the beverage was manipulated in VR, such that participants saw either a dark brown or light brown liquid as they sipped the coffee. A full factorial design was used so that each participant tasted each sweetness x color combination, Participants reported sweetness, creaminess, and liking for each sample. Results revealed that beverage color as viewed in VR significantly influenced perceived creaminess, with the light brown coffee rated to be creamier than dark brown coffee. However, beverage color did not influence perceived sweetness or liking. The present study supports the role of VR as a means of conducting food perception studies, either to gain a better understanding of multisensory integration, or, from an industry perspective, to enable rapid product testing when it may be time-intensive or costly to produce the same range of products in the real-world. Furthermore, it opens potential future opportunities for VR to promote healthy eating behavior by manipulating the visual appearance of foods.