## 3 Results and Discussion
### Characteristics of Dark and Strong Dark Ale Beer Samples  
The purpose of this study was to brew a dark ale beer, which was upgraded to a strong dark ale beer by adding carob syrup. The difference between the two beer categories is that a dark ale has lower final alcohol by volume (ABV), while when upgraded to a strong dark ale, the expected ABV significantly increases. According to the process of alcoholic fermentation, the yeasts added to the beers metabolize the sugars present in the initial \begin{table}
\begin{tabular}{c c c} \hline \hline
**Sample** & **pH** & **Brix** \\ \hline Carob syrup A (Uniwa) & 5.08 & 67.80 \\ Carob syrup B (Uniwa) & 4.91 & 64.30 \\ Carob syrup C (Uniwa) & 5.08 & 71.35 \\ Carob syrup D (Crete) & 5.41 & 74.43 \\ Commercial Carob syrup & 5.31 & 72.61 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Measurements of pH and Brix of carob syrups prepared in the laboratory and commercially available carob syrup. mallts, resulting in the production of ethanol and carbon dioxide as the final fermentation products. Therefore, when carob syrup is used as an additive to the initial beer, it provides a higher concentration of sugars and an increase in Plato, which can be consumed by yeasts, producing higher alcohol percentages. Thus, through the availability of sugars, the initial dark ale is enriched and upgraded to a strong dark ale beer. Simultaneously, in addition to providing carbohydrates, carob syrup enriches the final products with other equally important components, such as polyphenols. Typically, dark malts rich in sugars and other ingredients are used in stouts and dark ale beers, giving the final product an intense flavor, characteristic aroma, and dark color [32]. At the beginning of the beer fermentation process (t = 0 days), the Plato values for the dark ale beer with 6% ABV were 13.8 \({}^{\circ}\)P, for the strong dark ale carob beer with 8% ABV, they were 18.8 \({}^{\circ}\)P, and finally, for the strong dark ale carob beer with 10% ABV, they were 23.8 \({}^{\circ}\)P (Table 3). The consumption of fermentable sugars resulted at the end of the first fermentation process (t = 30 days), at Plato 3.8 \({}^{\circ}\)P for the dark ale beer with 6% ABV, 4.8 \({}^{\circ}\)P for the strong dark ale carob beer with 8% ABV, and finally, 6.3 \({}^{\circ}\)P for the strong dark ale carob beer with 10% ABV. No significant changes were expected at the final Plato values at the end of the second fermentation since only a small amount of dextrose (6.5 g/1 L of beer) was added, and it was mostly a product maturation step (bottle conditioning) in order to generate carbon dioxide in the final products. Therefore, for the dark ale beer with 6% ABV, the apparent fermentation degree was 72.46%, for the strong dark ale carob beer with 8% ABV, it was 74.46%, and finally, for the strong dark ale carob beer with 10% ABV, it was 73.52%, at the end of the first fermentation. Based on the fermentable sugars present in both the wort and carob syrups, these percentages are deemed acceptable [33]. The actual final % ABV of beers was very close to the expected: 5.57% for the control beer (expected 6%); 7.97% for the carob beer CB1 (expected 8%); and 9.97% for carob beer CB2 (expected 10%), values, which align with the limits specified in the literature for dark ale and strong dark ale beers (Brewers Association Beer Style Guidelines, n.d.). In all three samples, a decrease in pH was observed upon completion of the first fermentation (Table 3). The main cause was the production of weak organic acids (mainly lactic acid) during the fermentation of the samples, which affected the final pH value. According to the literature, the pH values for wort range from 5.3 to 5.6, while the pH limits for the final beer are from 4.3 to 4.6 [34]. Regarding sugars, in the dark ale beer with 6% ABV alcohol, all sugars come from the malt extracted during the mashing process. However, in the case of strong dark ale carob beers with 8% ABV and 10% ABV alcohol, sugars come from both malt and carob syrup added to the wort.