# Brewing with Unmulated Cereal Adjuncts: Sensory and Analytical Impacts on Beer Quality
## 3 Results and Discussion
### Analytical Evaluation of Adjunct Worts and Beers Versus an All Malt Control
#### 3.2.2 Finished Beer Quality Parameters  
Specifications of finished beers in the trial are reported in Table 5.  
Extract and final gravity principally indicate the sugar content of the word and beer, providing information on the efficiency of fermentation and the potential alcohol by volume (ABV) in the finished beer. In this study, original extract decreased relative to control with inclusion of all adjuncts, especially with 60% torrefied maize (Table 5). This is in agreement with prior published data where the inclusion of 20% maize yielded lower extract despite the fact that the starch extract yield potential of maize is greater than that of barley [25; 26]. At the end of fermentation, maize and rice beers were characterised by lower extract compared with the all-malt beer, in agreement with previous studies with maize adjunct [26]. A slightly higher apparent attenuation was observed for the maize and rice beers. The beer pH ranged from 4.01 to 4.49 which is within the expected pH range for lager beers [27]. The pH of beer is important when considering the sensory profile, it has been previously reported that low pH beers become more'sharp' and have an increased sour taste [18; 28]. The intensity of sour taste is related to the total concentration of free and undissociated hydrogen ions [18]. This could provide an explanation for the significant increase in sourness observed by the panel with the 60% maize sample, as the 60% maize beer had the lowest pH (4.01). Nitrogenous compounds in wort and beer have buffering \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline  & **Malt** & \multicolumn{2}{c}{**Barley (A)**} & \multicolumn{2}{c}{**Barley (B)**} & \multicolumn{2}{c}{**Maze**} & \multicolumn{2}{c}{**Rice**} & \multicolumn{2}{c}{**Wheat**} \\  & **100\%** & **30\%** & **60\%** & **30\%** & **60\%** & **30\%** & **60\%** & **30\%** & **60\%** & **30\%** & **60\%** \\ \hline \multicolumn{10}{c}{Wort FAN*} \\ (mg/L) & 243 \(\pm\) 26 & **184 \(\pm\) 1** & **127 \(\pm\)** 6 & **140 \(\pm\)** 2 & **85 \(\pm\)** 4 & **114 \(\pm\)** 10 & **58 \(\pm\)** 5 & **95 \(\pm\)** 15 & **61 \(\pm\)** 2 & **141 \(\pm\)** 11 & **79 \(\pm\)** 9 \\ \hline \multicolumn{10}{c}{* Free amino nitrogen concentration was standardised to 10 \({}^{\circ}\)P. ANOVA with [PERSON]’s post hoc analysis was used to compare the word FAN concentration. **Bold font** denotes the samples that were significantly different compared to the all malt control (\(p<0.01\)).  
\end{table} 
Table 4: Free amino nitrogen of adjunct word samples. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & **Original Extract** & **Final Gravity** & **Apparent** & **ABV** & **pH** & **BU** & **Colour (EBC)** & **Total Polyphenol Content** \\  & **(TP)** & **(TP)** & **Attenuation (\%)** & **(\%)** & **pH** & **BU** & **Colour (EBC)** & **(mg/L)** \\ \hline
100\%\_Malt & 11 & 1.8 & 84 & 4.8 & 4.48 & 17 & 10 & 170 \(\pm\) 10 \\
30\%\_Barley (A) & 9.4 & 1.8 & 81 & 4 & 4.45 & 19 & 8 & 137 \(\pm\) 5 \\
60\%\_Barley (A) & 10 & 2.6 & 75 & 3.8 & 4.49 & 17 & 8 & 160 \(\pm\) 3  
capacity and are important in establishing the pH. Adjuncts such as rice and maize contain low levels of nitrogenous compounds and phytase, the enzyme responsible for the breakdown of phytic acid to release phosphates. Therefore, adjuncts lessen the buffering capacity of wort and beer, leading to lower pH values [28]. Increasing nitrogenous compounds in the wort or reducing the amount of free hydrogen ions when brewing with adjunct material could potentially minimise this off flavour obtained in the 60% maize sample. The beers produced with unmalted adjuncts presented a lighter colour in comparison to the all-malt beer. Brewing with torrefied rice and maize generated beers of lighter colour relative to the all malt control. It has been previously reported that maize causes a decrease in beer colour proportional to the ratio of its addition, owing to low soluble nitrogen content and therefore less Maillard products which are the main source of beer colour [16; 17].