## 4 Conclusions  
The findings from this study showed that the brewing condition, water temperature, C2 WR, and coffee mesh size influence the TDS of CBC. The optimized brewing conditions for CBC were water temperature (4 \({}^{\circ}\)C), C2 WR (1:14), coffee mesh size (0.71 mm), and extraction time (24 h). The comparison between CBC and hot brew coffee samples with similar TDS revealed that there was no significant difference in total phenolic content or antioxidant activity as measured by the FRAP and DPPH radical scavenging assays. Even though the TDS and pH were similar for both samples, the titratable acidity was higher in CBC at all endpoints. The volatile compounds, caffeine content, and organic acid concentration were significantly higher in CBC than in the hot brew. In brief, CBC may not render higher health-beneficial properties than the hot brew, especially in terms of antioxidant activities and total phenolic content. However, the cold brew method can result in a difference in sensory properties and a higher caffeine content. The model for the prediction of TDS can also benefit food services or industries for the optimization of brewing conditions to obtain different characteristics of CBC. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/foods12122412/s1](https://www.mdpi.com/article/10.3390/foods12122412/s1)]([https://www.mdpi.com/article/10.3390/foods12122412/s1](https://www.mdpi.com/article/10.3390/foods12122412/s1)), Table S1: SRM transition and collision energies used in LC-ESI-MS/MS to detect caffeine; Table S2: chromatographic parameters, retention time, recovery of standard, concentration ranges and detection system of caffeine standard; Figure S1: high-performance liquid chromatograms of (A) organic acid standards, (B) cold brew coffee samples, and (C) hot brew coffee samples; Figure S2: liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI_MS/MS) chromatograms of (A) phenolic standards of cold brew coffee and (B) hot brew coffee samples; Figure S3: LC-ESI-MS/MS chromatograms of caffeine standards at (A) concentration 0.625; (B) concentration 1.25; and caffeine chromatograms of (C) cold brew and (D) hot brew coffee samples. **Author Contributions:** Conceptualization, N.H.Z., W.S., U.S. and C.S. ; methodology, N.H.Z., W.S., U.S. and C.S. ; validation, W.S., U.S. and C.S. ; formal analysis, N.H.Z., K.W., S.T. and W.C.; investigation, N.H.Z., K.W., S.T. and W.C.; resources, W.S., U.S. and C.S. ; data curation, N.H.Z., K.W., W.C., \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Organic Acid** & \begin{tabular}{c} **Cold Brew Coffee** \\ **(mg/mL)** \\ \end{tabular} & \
\begin{tabular}{c} **Hot Brew Coffee** \\ **(mg/mL)** \\ \end{tabular} &
\begin{tabular}{c} **\(p\)-Value** \\ \end{tabular} \\ \hline Oxalic & 0.2441 \(\pm\) 0.0166 & ND & 0.0015 \\ Tartaric & ND & ND & \\ Quinic & 9.9074 \(\pm\) 0.3222 & 8.9293 \(\pm\) 1.4168 & 0.3541 \\ Formic & 6.3737 \(\pm\) 0.3506 & 2.8997 \(\pm\) 1.6198 & 0.0596 \\ L-malic & 225.0592 \(\pm\) 2.5920 & 179.9038 \(\pm\) 1.1090 & 0.0002 \\ L-ascorbic & 0.4428 \(\pm\) 0.0067 & 0.3170 \(\pm\)0.0204 & 0.0048 \\ Acetic & 15.1426 \(\pm\) 0.2670 & 11.1902 \(\pm\) 0.9038 & 0.0117 \\ Citric & 10.6322 \(\pm\) 0.7767 & 6.5674 \(\pm\) 0.5031 & 0.0029 \\ Furrmaric & 0.0428 \(\pm\) 0.0012 & 0.0297 \(\pm\) 0.0029 & 0.0081 \\ Succinic & 28.4802 \(\pm\) 4.3241 & 0.3638 \(\pm\) 0.6301 & 0.0069 \\ Propionic & 0.4258 \(\pm\) 0.0100 & ND & 0.0002 \\ \hline \hline \end{tabular} Statistically significant is considered at \(p\) < 0.05; results are the mean \(\pm\) standard deviation from triplicate extraction.  
\end{table} 
Table 10: Comparison of the organic acid profile of cold and hot brew coffee with HPLC. W.S., U.S. and C.S. ; writing--original draft preparation, N.H.Z. ; writing--review and editing, W.S., U.S. and C.S. ; visualization, N.H.Z., W.S., U.S. and C.S. ; supervision, W.S., U.S. and C.S. ; project administration, C.S. ; funding acquisition, C.S.