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An another important step wort boiling, that lead to inactivation of enzymes, evaporation of water, color development, sterilization of the wort, removal of undesirable flavor components, formation of aromatic compounds, acidification of wort, isomerization of hop acids that provide bitterness to beer and precipitate haze-forming protein.

Then followed by fermentation, in which the conversion of wort sugars into alcohol and flavor components by yeast; then maturation, in which yeast settles and removed along with other undesirable components; followed by filtration and packaging of final product.

MATERIALS AND METHODS

Materials for brewing
Pilsner malts (Weyermann, Germany), Saaz pellet Hops (Hopsteiner) and Saflager S-189 lager yeast (Fermentis) were procured from local distributors and used for brewing.   
Wort production
Pilsner malt was milled and mashed using water grist ratio of 1:3. Mashing was done by using different time temperature combinations as:

1. Mash in was at 45°C and held for 20mins, then temperature was raised with the rate of 1°C/min to 52°C and held for 30mins then raised to 63°C and held for 30mins then  finally raised to 72°C and held  for 20mins followed by at 76°C for 2mins for  mash out.
2. In second method, mash in was done at 65°C and held for one hour and followed by 76 °C for 2mins and mash out.
3. In Third, Mash in was done at 62°C and held for 45mins followed by 72°C and held for 20 mins and mash out at 76°C. An iodine test was carried out before mash out temperature to con firm conversion. After completion of mashing, wort was filtered using Whatman filter paper and subjected to boiling.

Wort Boiling
Then boiling was done and three different time intervals of 60, 90 and 120 min were used by boiling at 100.0 ± 1°C. After boiling, the wort was held for 30mins for turb removal and for further wort analysis; it was cooled to 4°C.

Table 1: Wort Samples

Hop Addition
Hops addition was done in two stages and observed bitterness of final product. First hops addition (1g hop pellets for 100g malt) was done after 15mins of start of boiling and second hops addition (1g hop pellets) was done at last 30mins of wort boiling of every batch.
Fermentation

Pre-rehydrated dry yeast pitched into the wort prepared from the above different methods and fermentation was carried out at 10°C for 6 days and chill back at 4°C for 2 days followed by maturation at 1°C for 7 days.

Table 2: Beer Samples

Wort and Beer Analysis
All samples of wort produced by using different methods were analyzed for following parameters. All analysis were performed in triple samples, therefore the reported data are the mean of three values.
pH
The pH was measured by using a pH-meter. Wort pH was determined directly while the beers were degassed before analysis.
Total polyphenols
Total polyphenols (TP) content was determined according to the Singleton method (1999).
Total soluble nitrogen
The soluble nitrogen content of wort and beer was determined using the Kjeldahl method.

RESULTS AND DISCUSSION

The effect of variation in mashing and boiling profile on wort and beer properties was compared. Three different mashing profiles were used having same raw material and their effects were evaluated on the worts and beers by determining the pH, the total soluble nitrogen and total polyphenols.
Wort pH is one of main characteristic of the recipe and is uniform from brew to brew within a beer brand. Any variations in recipe and process affect fermentation, beer flavour and flavour stability.  The amount of toal nitrogen in wort plays an important role during beer fermentation, and greatly effects beer flavour. Wort nitrogen comprises protein content and the free amino nitrogen which is fundamental for yeast nutrition (Meillegard & Peppard, 1986). The nitrogenous compounds present in beers vary greatly in their chemical configuration and that effects beer odour, flavour, character etc. The amino compounds present in final beer are almost exclusively nitrogenous compounds that are not utilized by yeast (Montanari et al., 2005).
Table 3 reports the pH value, total polyphenols and total nitrogen of wort samples produced by using different mashing profiles. Our results confirmed literature data.

Table 3: the pH value, total polyphenols and total nitrogen of wort samples

The phenolic compounds present in beer also responsible for the total antioxidant capacity of plasma (TRAP). They contribute to astringency and colour, serve as browning substrates, participate in chill haze formation and are responsible for overall beer stability. The pH, total nitrogen and Total polyphenols were compared statistically.

Table 4: Specific gravity (SG), Evaporation and total nitrogen of wort samples

It was observed that evaporation rate increase with increase in boiling time. This is due to increase in water evaporation upon prolonged boiling and that leads to increase in Specific gravity of wort.
It was observed that there is decrease in total nitrogen with the increase in boiling time. Also, similar results were observed by Mishra & Speers (2020), they observed a 6-7% decrease in nitrogen fraction by an increase from 30 min to 120 min in boiling time.

Table 5: Color, total nitrogen and bitterness of beer samples

Generally, Mashing method 2 processes are used for less modified malt and if adjuncts having starch with a high gelatinization temperature are used, their precooking should be done in a separate vessel before being added in with the malt mash. In some previous studies, it was also observed that two similar commercial lager style beer of same brand have difference in their foam stability, despite using same raw materials and production processes (except wort boiling). It was believed that prolonged boiling lead to decrease in foam stability (Van Nierop et al., 2004).

CONCLUSIONS

Results indicated that not just recipes but also variation in brewing profile lead to changes in final product. The addition of the proteolytic step (52°C) in mashing profile had an effect on the total nitrogen of wort and beer. Also, increase in boiling time led to increase in color of beer as well.

 

REFERENCES

Meillegard, M. C., & Peppard, T. L. (1986). The one flavour of beer. In: Morton, I. D., & MacLeod, A. J. (eds) Food flavours, Part B. The flavour of beverages, Elsevier, Amsterdam, pp 99–170.
Mishra, A., & Speers, R. A. (2020). Wort boil time and turb effects on fermentability. Journal of the American Society of Brewing Chemists.
Montanari, L., Floridi, S., Marconi, O., Tironzelli, M., & Fantozzi, P. (2005). Effect of mashing procedures on brewing. Eur Food Res Technol 221, 175–179.
Singleton, V. L., Orthofer, R., & Lamuela-Raventos, R. M. (1999). Analysis of total phenols and other oxidation substrates and antioxidants by means of Folin-Ciocalteu reagent. Methods Enzymol. 299, 152-178.
Van Nierop, S. N. E., Evans, D. E., Axcell, B. C., Cantrell, I. C., & Rautenbach, M. (2004). Impact of different wort boiling temperatures on the beer foam stabilizing properties of lipid transfer protein 1. Journal of Agricultural and Food Chemistry, 52, 3120–3129.