THE EFFECT OF COLD BREW AND HOT BREW EXTRACTION METHODS AND DURATION OF FERMENTATION ON THE QUALITY OF ROBUSTA COFFEE WINE (Coffea canephora) TEMANGGUNG

Recently, a new trend called cold brewing gained popularity in the tea and coffee beverage industry. Cold brew and hot brew black tea may have different sensory qualities and antioxidant levels because of their polyphenolic properties and brewing processes. The objectives of this study were to determine antioxidant properties and polyphenolic content of commercial brands of cold brew and hot brew black tea. The total phenolic content of the cold brew tea was determined to be 0.19 mg/mL gallic acid equivalents/100 g and hot brew tea was 0.43 mg/mL gallic acid equivalents/100 g when assayed by Folin-Ciocalteu’s reagent method. The total flavonoid content of the cold brew tea was 0.40 mg/mL catechin equivalents/100 g and hot brew was 1.01 mg/mL catechin equivalents/100 g. Moreover, antioxidant capacity of cold brew and hot brew black tea was analyzed where their ability to scavenge DPPH radicals was 86.3% and 88.1% respectively. There was a significant difference in total phenolic content between hot brew and cold brew (p = 0.004). Similarly, there was a significant difference in total flavonoid between cold brew and hot brew (p = 0.004). Additionally, there was a significant difference in DPPH scavenging activity between cold brew and hot brew (p = 0.016). Overall, it can be concluded that although cold brew tea contained a lower amount of phenolics and flavonoids as compared to hot brew tea, they both were able to scavenge DPPH radicals in nearly same capacity.

Coffee is one of the most popular beverages which are rich in sensory attributes. What is the best time for brewing coffee after roasting is important question for consumer. In general, people do not directly brew coffee that has just been roasted. The chemical change which causes sensory changes still continues during the resting time. Enjoying coffee is about taste, everyone has different preferences. Some people prefer bitter coffee; some people like the sour taste and some others consume sweet coffee. Therefore, information about sensory and chemical profile is needed to give several options for consumer to choose their brewing method and brewing time before the coffee has decreased in sensory quality. This current study aims to know sensory and chemical changes of cold and hot brew Arabica coffee at various resting time. The materials were coffee beans Arabica Jawa Gunung Halu obtained from Cibeber, Sidangkerta Village, Mekarsari District, Bandung Regency, West Java. The roasted bean stored at various resting time (1, 3, 5, 7, and 9 days) than brewed in cold and hot brew methods. Sensory evaluation was conducted by 10 trained panelists using quantitative descriptive analysis (QDA). Furthermore, chemical analyses which were evaluated consist of the value of pH, brix and Total Dissolved Solid (TDS). The results showed that longer resting time followed by sensory characteristics changes on aroma, after taste, sweetness that is in line with chemical attributes change in Brix. Moreover color change in line with TDS change. While the different brewing techniques show that hot brew has higher value than cold brew in most all of parameters except Brix value. Keywords — chemical, coffee, panelists , resting time, sensory

Coffee is one of the most popular beverages globally, cherished for its unique taste, aroma, and the stimulating effects of its caffeine content. The proliferation of creative coffee shops has introduced various new methods for enjoying coffee, including cold and hot brew techniques. These processing techniques can significantly influence the physicochemical characteristics of coffee, particularly its caffeine content. This study compares the caffeine content in Robusta coffee using cold and hot brewing techniques. The hot brew coffee was prepared using water at approximately 96°C with a French press for six minutes. In contrast, the cold brew method involved brewing with water at room temperature (20-25°C) using a French press, followed by storage for 12 hours in a refrigerator (2-8°C). Qualitative analysis involved examining the color reaction, while quantitative analysis was conducted using High-Performance Liquid Chromatography (HPLC). HPLC is a highly accurate method that is extensively used in the food and pharmaceutical industries. The results indicated that the caffeine content in cold-brewed Robusta coffee was significantly higher, with a concentration of 44.63 μg/mL ± 0.199% and a Relative Standard Deviation (RSD) of 0.4459%. Conversely, hot-brewed coffee showed a caffeine concentration of 23.96 μg/mL ± 0.278%, with an RSD of 1.1602%. The parametric Analysis of Variance (ANOVA) revealed a significance value of 0.000 (p < 0.05), indicating a significant difference in caffeine levels between hot-brewed and cold-brewed coffee. These findings suggest that the choice of Robusta coffee processing technique can be crucial for individuals with specific health conditions seeking to manage their caffeine intake.

Ekstraksi teknik cold brew mulai berkembang dikalangan masyarakat yaitu menggunakan air bersuhu ruang yang didiamkan 6-18 jam. Metode ini digunakan untuk menyeduh kopi atau teh dengan kualitas yang baik tapi membutuhkan waktu yang cukup lama. Oleh karena itu perlu metode ekstraksi yang lebih cepat tanpa mengurangi kualitas produk yang dihasilkan. Salah satunya yaitu Ultrasonic assisted extraction (UAE) merupakan metode ekstraksi berbantu ultrasonik yang dapat menghasilkan ekstrak cukup baik pada suhu ruang dalam waktu yang lebih singkat bahkan mampu menghasilkan ukuran partikel dalam skala nanometer. Untuk itu, dilakukan penelitian ekstraksi teh hijau menggunakan metode UAE dalam temperatur rendah (dibawah suhu ruang). Tujuan Penelitian ini adalah mengetahui pengaruh suhu dan waktu ekstraksi terhadap ukuran partikel menggunakan UAE cold brew serta menentukan waktu dan suhu optimum pengekstraksi untuk menghasilkan berat terekstraksi tertinggi dan melakukan analisis distribusi ukuran partikel ekstrak yang dihasilkan. Proses UAE menggunakan air suhu (10, 15, 20 ºC) dan waktu (5, 10, 30 menit). Sebagai kontrol dilakukan ekstraksi maserasi cold brew menggunakan suhu ruang selama 12 jam didiamkan pada lemari pendingin dan hot brew suhu 70ºC selama 10 menit. Analisis kepekatan warna dilakukan untuk menentukan sample yang akan diuji PSA. Hasil analisis kepekatan warna menunjukan ekstraksi UAE suhu 10ºC dengan variasi waktu 5,15,30 menit yang paling sesuai dengan karakteristik larutan teh hijau. Uji PSA menghasilkan ukuran paling kecil pada suhu 10ºC selama 30 menit dengan rata-rata ukuran 293.64 nm. Waktu dan suhu optimum untuk menghasilkan berat terekstraaksi terbanyak pada suhu 20ºC 30 menit sebesar 0,82 gram dari 6 gram sample teh hijau. Hasil ini menunjukan ekstraksi UAE dapat mempersingkat waktu, meningkatkan berat terekstraksi dan menghasilkan ukuran nanometer.Kata kunci : Cold Brew; Ekstraksi; PSA; Teh Hijau; UAE ABSTRACT The extraction of cold brew techniques has begun to develop among the community, by using room temperature water that is left to rest for 6-18 hours. This method is used to brew coffee or tea with good quality but it takes a long time. Therefore, it needs a faster extraction method without reducing the quality of the product produced. One of them is Ultrasonic assisted extraction (UAE) which is an ultrasonic-assisted extraction method that can produce extracts quite well at room temperature in a shorter time and is even able to produce particle sizes on the nanometer scale. For this reason, a research on green tea extraction was carried out using the UAE method at low temperature (below room temperature). The purpose of this study is to determine the effect of temperature and extraction time on particle size using UAE cold brew and to determine the optimum extraction time and temperature to produce the highest extracted weight and analyze the particle size distribution of the extracts. The UAE process uses water temperature (10, 15, 20 ºC) and time (5, 10, 30 minutes). As a control, the cold brew maceration extraction was carried out using room temperature for 12 hours, left in the refrigerator then hot brew at 70ºC for 10 minutes. Color density analysis is carried out to determine the sample to be tested for PSA. The results of the color density analysis showed that the UAE extraction temperature was 10ºC with a time variation of 5.15.30 minutes which was the most suitable with the characteristics of the green tea solution. The PSA test produced the smallest size at 10ºC for 30 minutes with an average size of 293.64 nm. The optimum time and temperature to produce the most extracted weight were at 20ºC 30 minutes at 0.82 grams from 6 grams of green tea samples. These results showed that the UAE extraction can shorten the time, increase the weight extracted and produce a nanometer size.Keywords : Cold Brew; Extraction; PSA; Green tea; UAE

Cold brew coffee is a brewing method that is increasing in prevalence. While it has been anecdotally suggested that this method may provide a more aromatic and flavourful coffee product, there is little research published that looks at the concentration of caffeine or other coffee substituents in cold brew coffee. The potential alteration in chemical composition in cold brew provides a few interesting avenues for research. Can caffeine in cold brew be quantified by conventional methods? If so, how does the caffeine profile of cold brews relate to hot brew methods? Here we report the caffeine content and variability in small batch cold brew coffee and show that HPLC/UV-Vis, a standard method for quantitation of caffeine in other extraction methods, is useful for detection of caffeine in cold brew coffee. The mean concentration of caffeine in an average 355 mL serving was found to be 207.22 ± 39.17 mg over five distinct batches of cold brew coffee concentrate. Cold brew preparation methods produce similar quantities of caffeine as hot brew preparation, yet may have increased storage capabilities including improved retention of flavonoids and other secondary metabolites. Therefore, cold brew may provide utility in clinical trials examining caffeine and the effect of other components of coffee as it is commonly consumed.

European countries have recently started experimenting with growing and producing their own teas in small quantities, mainly for the specialty tea sector. To characterize European teas, this study investigated a set of five tea types obtained from different Camellia sinensis varieties/cultivars, representing various oxidation grades (green, white, yellow, oolong, black), all grown and processed in the only tea garden in Europe (in Germany) that focuses on all five types. Hot and cold brews were studied by measuring the total phenolic (TPC) and flavonoid contents (TFC), the antioxidant capacity and UV-Vis spectra, also with the objective of discriminating between the different tea types and the different plant varieties. The dried leaves were analyzed to measure the content of essential and toxic elements and by ATR-FTIR spectroscopy to determine a chemical fingerprint for identifying the tea varieties and types. The average levels of TPC (hot brew = 5.82 ± 2.06; cold brew = 5.4 ± 2.46 mM GAEq), TFC (hot brew = 0.87 ± 0.309; cold brew = 0.87 ± 0.413 mM CAEq), and antioxidant capacity (ORAC assay-hot brew = 20.9 ± 605; cold brew = 21.8 ± 8.0 mM TXEq, ABTS assay-hot brew = 15.2 ± 5.09; cold brew = 15.1 ± 5.8 mM TXEq, FRAP assay-hot brew = 9.2 ± 3.84; cold brew = 10.4 ± 5.23 mM AAEq) observed compared well with those from other parts of the world such as China, Africa, and Taiwan. The hazard quotient <1 and the hazard index of 0.14 indicate that there is no non-carcinogenic risk from consumption of these teas. The obtained information is essential for elucidating the characteristics and the impact of tea processing and tea variety on the health benefits of these tea products coming from a single European tea garden. This multifaceted approach would help tea growers in Europe increase their knowledge on the health attributes of the teas they grow, ultimately leading to optimization of the nutraceutical properties of these teas.

A long extraction time for traditional cold coffee brewing considerably reduces the production efficiency of this type of beverage. Herein, a new ultrasound-assisted cold brewing (UAC) method was established. The feasibility of UAC was assessed by comparison with main physicochemical characteristics, non-volatile and volatile compounds in coffee extracts produced by hot brewing and conventional static cold brewing methods. Compared to the static cold brews, the levels of total dissolved solids, total lipids, proteins, and titrated acids of UAC coffee extracts increased by 6–26%, 10–21%, 26–31%, and 12–15%, respectively. Caffeine, chlorogenic acid, and trigonelline concentrations were also determined by HPLC. Based on the volatile profiles obtained by HS-SPME-GC/MS, the aroma compounds in UAC was significantly different (p < 0.05) from hot brews but similar to static cold ones, suggesting that ultrasonication compensated for the time of the static cold brewing, thereby considerably shortening the extraction time (1 h vs. 12 h). This work demonstrated that the combination of ultrasound-assisted with cold brew could produce coffee with good flavor and increase the extraction efficiency, which may provide an option for the acceleration of the cold brew coffee process.

Tea is one of the plantation crops which contributes to 3.27% of the Gross Domestic Product (GDP) in Indonesia. As one of Indonesia’s export commodities, tea plays a big role in foreign exchange revenue. Among various kinds of processed tea drinks, 14.36% of tea consumers in Indonesia have a preference for consuming ready-to-drink (RTD) tea, implying its market potential in Indonesia. Furthermore, the increasing trend of healthy products resulted in the rise of the probiotic beverage market globally. Therefore, an RTD tea product with the addition of Lactobacillus plantarum Dad-13 has been developed, named ProbioTea. This study discusses the development of the ProbioTea product and vulnerability analysis of the two processes used: cold brew and hot brew. The study aimed to determine the level of vulnerability at each stage of ProbioTea manufacturing to reduce the risk of failure in large-scale production. This study also investigated antioxidant contents, cell viability, pH, and the visual appearance of ProbioTea. The result showed that the mixing and storage process has a high vulnerability to both cold and hot brew methods. The result of the assessment of risk vulnerability in the ProbioTea production process showed no risk with an extreme level of vulnerability. Thus, it indicated that the risk in the ProbioTea production process can be managed properly. The percentage of antioxidants in the cold brewing method was 51.25 - 71.76%, while the hot brewing method shows 44.89 - 54.74%. After storage, ProbioTea with the cold brew method experienced an increase in antioxidants because the low temperature was able to protect the bioactive compounds in tea. Meanwhile, there was no significant difference in the cell viability of ProbioTea processed on the cold and hot brew. After storage, the cell viability contained in ProbioTea was more than 6.8 CFU/mL. The acidity of ProbioTea processed in both cold and hot brew was not significantly different. This research concluded that the ProbioTea product is good.

Cold brew coffee is often described as sweeter or less acidic than hot brew coffee. Such comparisons, however, are potentially confounded by two key effects: different brew temperatures necessarily change the extraction dynamics and potentially alter the resulting brew strength, and different consumption temperatures are well known to affect perceived flavor and taste. Here, we performed a systematic study of how extraction temperature affects the sensory qualities of full immersion coffee. The investigation used a 3 × 3 × 3 factorial design, with coffee from three different origins representing different post-harvest methods (washed, honey-processed, and wet-hulled), each roasted to three different levels (light, medium, and dark), and each brewed at three different temperatures (4 °C, 22 °C, and 92 °C). All coffees were brewed to equilibrium, then diluted to precisely 2% total dissolved solids (TDS) and served at the same cold temperature (4 °C). We find that four attributes exhibited statistically significant variations with brew temperature for all origins and roast levels tested, with bitter taste, sour taste, and rubber flavor all higher in hot brewed coffees, and floral flavor higher in cold brewed coffee. However, there were strong interactions with origin and roast, with several additional attributes significantly impacted by temperature for specific origins and roast levels. These results provide insight on how brew temperature can be used to modulate the flavor profile of full immersion coffee.

The extraction kinetics and equilibrium concentrations of caffeine and 3-chlorogenic acid (3-CGA) in cold brew coffee were investigated by brewing four coffee samples (dark roast/medium grind, dark roast/coarse grind, medium roast/medium grind, medium roast/coarse grind) using cold and hot methods. 3-CGA and caffeine were found at higher concentrations in cold brew coffee made with medium roast coffees, rather than dark roast. The grind size did not impact 3-CGA and caffeine concentrations of cold brew samples significantly, indicating that the rate determining step in extraction for these compounds did not depend on surface area. Caffeine concentrations in cold brew coarse grind samples were substantially higher than their hot brew counterparts. 3-CGA concentrations and pH were comparable between cold and hot brews. This work suggests that the difference in acidity of cold brew coffee is likely not due to 3-CGA or caffeine concentrations considering that most acids in coffee are highly soluble and extract quickly. It was determined that caffeine and 3-CGA concentrations reached equilibrium according to first order kinetics between 6 and 7 hours in all cold brew samples instead of 10 to 24 hours outlined in typical cold brew methods.

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

The acidity and antioxidant activity of cold brew coffee were investigated using light roast coffees from Brazil, two regions of Ethiopia, Columbia, Myanmar, and Mexico. The concentrations of three caffeoylquinic acid (CQA) isomers were also determined. Cold brew coffee chemistry was compared to that of hot brew coffee prepared with the same grind-to-coffee ratio. The pH values of the cold and hot brew samples were found to be comparable, ranging from 4.85 to 5.13. The hot brew coffees were found to have higher concentrations of total titratable acids, as well as higher antioxidant activity, than that of their cold brew counterparts. It was also noted that both the concentration of total titratable acids and antioxidant activity correlated poorly with total CQA concentration in hot brew coffee. This work suggests that the hot brew method tends to extract more non-deprotonated acids than the cold brew method. These acids may be responsible for the higher antioxidant activities observed in the hot brew coffee samples.

Cascara, the dried husk of coffee cherries, has attracted attention as a potential beverage due to its unique flavour profile and potential health benefits. Traditionally, cascara is prepared using hot brewing methods. However, recent interest in cold brewing methods has led to research on how temperature affects the functional properties of cascara beverages. Colour (CIE L*a*b*), total dissolved solids and titratable acidity were determined in cascara beverages prepared at 5, 10, 15 and 20 °C. The concentration of phenols and flavonoids, as well as antioxidant properties were evaluated using spectrophotometric methods. Caffeine, chlorogenic acid and melanoidins were quantified by HPLC. The mineral composition was determined using inductively coupled plasma mass spectrometry (ICP-MS). The results were compared with a hot-brewed cascara beverage. Cold brewing resulted in significantly higher concentrations of total phenolic compounds, expressed as gallic acid equivalents (ranging from 309 to 354 mg/L), total flavonoids, expressed as quercetin equivalents (11.8-13.6 mg/L), and caffeine (123-136 mg/L) than the hot-brewed cascara beverage sample (p<0.05). Temperature had a noticeable effect on most variables, although the effect appeared to be random. In particular, concentrations of caffeine (p<0.01) and copper (p<0.001) were highest in beverages prepared at 20 °C and decreased with decreasing brewing temperature. Multivariate analysis showed that minerals (As, Co, Mn, Sn, Mg and Ca), hue and phenolic concentration contributed to the first principal component, which mainly differentiated the hot-brewed sample. Antioxidant-related variables, total titratable acidity and Se contributed most to the second principal component, which facilitated the separation of samples brewed at 5 °C. To our knowledge, this is the first study to suggest that temperature affects the functional properties of cascara beverage produced by the cold brewing method. Experimental evidence supports the existence of a direct proportionality between caffeine and copper concentrations and brewing temperature.

This study investigated a continuous circulation cold brewing (CCCB) process using a modified single‐serve brewer that allowed recirculation of the brew within the single‐use capsules. The changes of total dissolved solids (TDS), titratable acidity (TA), caffeine and 5‐caffeoylquinic (5‐CQA) concentrations over time during the CCCB process were evaluated using two masses of coffee grounds (10 and 12.5 g). To elucidate the extraction process, Weibull distribution, pseudo‐first order, and pseudo‐second order models were fitted to the extraction kinetics data. The physicochemical quality of the brews produced from the CCCB process were also compared to brews produced though traditional cold brew steeping (separated by gravity and forced filtration) and single‐serve hot brewing processes. Significantly lower (p &lt; 0.05) TDS, TA, and 5‐CQA concentrations than traditional cold brew methods were observed. This observation was due to flow channeling/detachment phenomena in the coffee bed which resulted in localized flow and reduction of coffee‐water contact area. In comparison, the 30 min full immersion processes resulted in approximately 70% of the TDS, TA, and caffeine levels during the first 30 min of brewing, suggesting that cold brewing processes may not have to be &gt;8 h in length if these are the targeted brew quality indices.Practical applicationsThis study examined the kinetics and physicochemical quality of continuous circulation cold brewing of coffee and compared it to traditional full immersion cold brewing methods. The findings in this study indicated that: (1) The brew recirculation method explored was not on par with traditional full immersion cold brewing methods in terms of extraction yield due to flow channeling issues present in single‐use capsules; (2) The extraction time of traditional cold brewing processes can potentially be shortened on the basis of TDS, TA and caffeine content; (3) The choice of filtration mechanism is significant when considering the extraction yield of a brewing process.

Differences in brewing methods both from extraction time and brewing water temperature can affect the number of chemical compounds dissolved. This study applied the cold brew brewing method with high-speed stirring to Arabica Semendo coffee with extraction times of 15, 30, and 45 minutes at different particle sizes of coffee powder (coarse, medium, and fine) to obtain coffee with better characteristics than the commonly used brewing methods (hot brew and cold brew) and acceptable in sensory evaluation. The pH, viscosity, total soluble solids, total microbes, and sensory evaluation by hedonic tests on taste, color, and aroma were investigated. Coffee with high-speed stirred cold brewing for more than 30 minutes with finer coffee grounds had higher pH, viscosity, and total soluble solids than common brewing as a control. The size of the coffee grounds and the difference in brewing method did not affect microbial contamination. The results of the hedonic test on color, taste, and aroma in the cold brewing method of high-speed stirring produced coffee that was accepted by consumers and was not significantly different from the common brew.