## 3 Results
### SPME GC Results  
Figure 2 shows a typical chromatogram of a beer sample, demonstrating clear resolution of common alcohol and ester compounds and allowing several aroma compounds to be identified. Table 5 shows quantitative information for three common ester compounds. Several compounds were found to be below the detection limit for the method. Further optimization of the method may be possible to produce lower detection, however, the values determined are in a typical range for beer samples [12; 13]. The highest isoamyl acetate values were detected in samples 1 and 9, which were both characterized as Belgian style ales. The lowest ester concentrations were seen for the stout, Hefeweizen and English brown styles (samples 4, 5 and 6).  
### SPME GC Results  
Figure 2 shows a typical chromatogram of a beer sample, demonstrating clear resolution of common alcohol and ester compounds and allowing several aroma compounds to be identified. Table 5 shows quantitative information for three common ester compounds. Several compounds were found to be below the detection limit for the method. Further optimization of the method may be possible to produce lower detection, however, the values determined are in a typical range for beer samples [12; 13]. The highest isoamyl acetate values were detected in samples 1 and 9, which were both characterized as Belgian style ales. The lowest ester concentrations were seen for the stout, Hefeweizen and English brown styles (samples 4, 5 and 6).  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline  & **1** & **2** & **3** & **4** & **5** & **6** & **7** & **Average** & **Std. Dev.** & **\%RSD** \\ \hline \multicolumn{10}{c}{**Organic Acids**} \\ \hline Lactic Acid (mg/L) & 3934 & 3969 & 3945 & 3966 & 3966 & 3983 & 3972 & 3962 & 17 & 0.4 \\ Succinic Acid (mg/L) & 201 & 216 & 204 & 216 & 210 & 201 & 201 & 207 & 7 & 3.2 \\ Acetic Acid (mg/L) & 256 & 275 & 258 & 287 & 252 & 256 & 254 & 262 & 13 & 5.1 \\ \hline \multicolumn{10}{c}{**Alcohols**} \\ \hline Ethanol (mg/L) & 55,693 & 55,916 & 55,889 & 55,891 & 56,006 & 56,118 & 56,118 & 55,947 & 150 & 0.3 \\ Ethanol (r/v) & 7.06 & 7.09 & 7.08 & 7.08 & 7.10 & 7.11 & 7.11 & 7.09 & 0 & 0.3 \\ \hline \multicolumn{10}{c}{**Carohydrates**} \\ \hline Residual Dextrin (mg/L) & 20,880 & 21,143 & 20,950 & 21,056 & 21,424 & 20,301 & 19,949 & 20,815 & 512 & 2.5 \\ \hline \multicolumn{10}{c}{**Amino Acids**} \\ \hline Alanine (mg/L) & 174 & 179 & 168 & 165 & 171 & 159 & 179 & 171 & 7 & 4.4 \\ \hline \hline \end{tabular}
\end{table}
Table 4: \({}^{1}\)H NMR analysis—data processing reproducibility.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & **Isoamyl** & **Ethyl Caprylate** & **Ethyl Caprate** & **Other Compounds Identified** \\  & **Acetate (mg/L)** & **(mg/L)** & **(mg/L)** & **(mg/L)** \\ \hline
1 & 2.1 & 1.6 & 0.8 & Ethanol, ethyl acetate, isoamyl alcohol, ethyl butyrate \\ \hline
2 & 0.2 & 0.2 & BDL & Ethanol, ethyl acetate, isoamyl alcohol, ethyl butyrate, \(\beta\)-pinene \\ \hline
3 & ND & BDL & 0.9 & Ethanol, ethyl acetate, isoamyl alcohol, ethyl butyrate \\ \hline
4 & BDL & BDL & BDL & Ethanol, ethyl acetate, isoamyl alcohol, ethyl butyrate, linalool \\ \hline
5 & ND & BDL & BDL & Ethanol, ethyl acetate, isoamyl alcohol, ethyl butyrate \\ \hline
6 & BDL & BDL & BDL & Ethanol, ethyl acetate, isoamyl alcohol, ethyl butyrate \\ \hline
7 & 1.0 & BDL & 0.8 & Ethanol, ethyl acetate, isoamyl alcohol, ethyl butyrate, isoamyl propionate, \(\beta\)-pinene, any l butyrate \\ \hline
8 & 0.6 & 0.4 & 0.2 & Ethanol, ethyl acetate, isoamyl alcohol, ethyl butyrate, amly butyrate \\ \hline
9 & 3.4 & BDL & 0.6 & Ethanol, ethyl acetate, isoamyl alcohol, ethyl butyrate, ethyl valerate \\ \hline \multicolumn{10}{c}{BDL = Below Detection Limit, ND = Not Determined/Unacceptable Line Fit.} \\ \end{tabular}
\end{table}
Table 5: Concentrations of common ester compounds and other compounds identified.