FOSC 4081: Brewing Science Lab 3: Pilot-Scale Mashing and FermentationLab Completed: October 29, 2015

For

Dr. Andrew Macintosh

Submitted: November 13, 2015

_____________________________ _____________________________Jonathan Totten Matthew Zwicker B00450823 B00582641

Lab 3: Pilot-Scale Mashing and Fermentation

Executive Summary

Table of ContentsExecutive SummaryiiTable of ContentsiList of FiguresiList of Tablesii1Introduction32Material and Methods33Results and Discussion6References9

List of FiguresFigure 1: Kettle on the right and the mash tun with the added malt5Figure 2: Plate heat exchanger used for cooling and fermentation vessel6Figure 3: Calibration curve of absorbance vs yeast cell count9

List of Tables

iii

IntroductionCreating a well-balanced beer that will satisfy the palate of the consumer begins with the selection of quality ingredients including: hops, malt, yeast and water. Totten & Zwicker craft breweries is considering purchasing a major portion of malt for the 2015/16 fiscal year to brew their popular chocolate porter ale. To determine if the malt passes Totten & Zwickers standards of excellence, a pilot-scale mash and fermentation was completed. The objectives of the pilot-scale mashing and fermentation are: To analyze various mash parameters in a pilot-scale mash and become familiar with the mashing process. To analyze various fermentation parameters in a pilot-scale fermentation using standard procedures. To contrast fermentation data with a control fermentation for which you will be given the data. To model and compare the key fermentation parameters (density and absorbance) of both the experimental and control fermentations, using appropriate equations.

It is expected that the pilot-scale mash and fermentation will have similar results to the control

Material and MethodsThe lab consisted of two main parts: the mashing step and the fermentation step. To begin the mashing step the brewing water was pre-heated in the steam kettle. The EBC congress mash was used to determine the ratio of malt to water (1:4). The water from the kettle was transferred to the mash tun and kept at a constant temperature of 70oC. The malt was then added to the mash tun that consisted of 80% 2-row barley (11.76kg), 10% crystal malt (1.47kg), and 10% chocolate malt (1.47kg) for a total of 14.7 kg. During the mashing procedure frequent samples were collected to perform iodine tests, color and density tests. The mash was stirred with an oar before taking samples. Samples were taken at the beginning, end and sparging steps. Using the ESC-4.5.1 (Section 8.1.6) method, the saccharification (solution turns dark purple to yellow indicating sugar) of the mash was tested by taking samples every five minute until complete. The samples for the color and density were prepared by transferring to 50 mL of mash to centrifuge tubes and then the malt was crashed cooled on ice to 20oC to slow hydrolytic activity of the enzymes. The samples were then centrifuged for two minutes at 5300 rpm and then filtered through Whatman #4 paper. Using the ASBC Beer-10 method, the color of the mash was measured by measuring the absorbance at 430 nm wavelength with a spectrophotometer. The density of the malt was measured using the ASBC Beer-3 method and an Anton Parr densitometer. Figure 1 shows the kettle boiler on the right used to boil the water for the mash and the picture on the left shows the mash tun with the water and ground malt.

Figure 1: Kettle on the right and the mash tun with the added malt

After one hour the mash was filtered through a strainer and the malt was added back to the mash and the wort was added to the empty kettle. The wort was heat until it reached 100oC and then 50% of the fresh hops from Malagash, Nova Scotia and two cups of cascade hops were added. The wort was boiled for 25 minutes and the remainder of the fresh hops was added. Finally, the wort was boiled for a further five minutes. The hot wort was then transferred through a (type) plate heat exchanger to the fermentation vessel by transfer hoses. The heat exchanger was fitted with a thermometer, sight glass and oxygen insert. The plate heat exchanger cooled the hot wort from 100oC to 30oC and also injected medical grade oxygen from a compressed cylinder into the wort to oxygenate it before it entered the fermenter. It should be noted that during the transfer from the kettle to the fermentation vessel, the plate heat exchanger was clogged with hop debris from the kettle and a significant amount of wort was lost. Figure 2 shows the plate heat exchanger used for cooling on the left and the fermentation vessel on the right.

Figure 2: Plate heat exchanger used for cooling and fermentation vessel

An ale Smack pack brewing yeast was used for the fermentation. To count the yeast cells in suspension the ASBC Yeast-4 method was used. The fermentation continued over the weekend after the lab was completed (insert length of fermentation). The post analysis crew took samples at 9:00am, 1:30pm and 5:00pm the day after mash and fermentation to measure the density. Appendix A contains the tasks allocation for the mash crew, the boil fermentation crew, post analysis crew, and the clean-up crew.

Results and Discussion Mashing is a process by which wort is prepared. To begin the mashing process pre-heated water (or liquor) was transferred to a mash tun and then the malt was added. There are key physical differences between the wort and the mash. The mash is the combination of ground malted grains, water and sometimes supplementary enzymes and salts. On the other hand, the wort is the liquid extracted from the mashing process. The extraction process leaves few to no grain husks left in the wort. The wort contains the starch from the malted grains that is enzymatically broken down to sugars. There are typically two types of mashes; infusion mashing and decoction mashing. Infusion mashing is the process where the mash is heated to different temperatures at which specific enzymes work optimally. A single rest at one stable saccharification temperature is used in this technique. Decotion mashing is no longer a widely used technique due to the introduction of automated temperature control. The basic principle of this technique is to extract part of the mash from the system, boil it, and return it back to the rest of the mash. This process allows the use of physical pulping to help break down the cell walls in the malt in addition to raising the mash to a second temperature by mixing the two parts of the mash.During the mashing process a beta-glucanase rest is typically done at 40 degrees Celsius (oC) to break down the grains cell walls and make starches more available. Highly polymerized beta-glucans are located within the cell walls of the starchy endosperm of the malt. Beta glucans are polysaccharides such as cellulose which are made of glucose molecules connected by beta glycosidic bonds. At 70oC an alpha and beta amylase rest are typically down simultaneously. The beta-amylase enzyme becomes active first and begins by breaking down the starch chains from the end of the molecules, forming two chain glucose molecules (maltose). Alpha-amylase becomes active shortly after the beta-amylase where the starches are broken down from the inside of the starch molecule creating chains of one to four glucose molecules in length (dextrins or maltodextrins). It should be noted that barley does not contain alpha amylase; however, it does develop in the grain during the malting process.Calcium salts are sometimes added to the mashing process as the mash liquid (wort) can contain large amounts of phosphates that were derived from the ground malted grains. The phosphate ions can have a buffering effect where the hydrogen ions from the water are reacted with the phosphate, resulting in a pH increase. The added calcium will react with the phosphate by the following reaction:

The calcium phosphate is insoluble in the liquid and precipitates, releasing hydrogen ions and lowering pH. The lower pH improves beta-amylase activity thus increasing sugar extract content. The calcium ions also protect and stabilizes the alpha-amylase enzyme from inhibition by heat. The lowered pH will also provide a greater resistance to microbiological infection. Calcium is not added during our test mashing procedure because the outcome of the test mash is to determine the properties of the ground malt. Therefore, it is crucial to understand how the malt affects pH of the wort without the addition of other compounds such as calcium salts. Brewers generally manage pH values mostly for enhancement of enzyme performance in the mash. Beta and alpha amylase perform optimally between ranges of 5.4 to 5.6 and 5.6 to 5.8 respectively. pH is sometimes measured during mashing because pH is difficult to predict in advance even if a recipe is being followed. Enzyme activity during the mash is crucial and as mentioned before, a pH that is too high or too low will affect the activity of the enzyme and how much starch is converted to sugars. The presence of starch in the mash is measured by the iodine test. The iodine is usually added to the starch in the form of potassium iodide. This will usually start as a blue-black colour. Due to the structure of amylopectin in the starch, the combination of iodine and starch will form a yellow colour. As the starches become hydrolysed into smaller particles, the reaction which forms the yellow colour will stop occurring.

Where,Aw/w = % Alcohol (weight/weight)OE = Original Density (or Extract - oP at the beginning of fermentation) AE = Apparent Density (or Extract - oP at the end of fermentation)

Beers are reported in some parts of the world on a weight per weight basis; however, beer in Canada is reported in a volume per volume basis. Therefore the actual alcohol percentage in volume per volume is calculated by the formulas below:

Where,oP = Degree PlatoSG = Specific Gravity

Where,Av/v = % Alcohol (volume/volume)

An alcohol level of 3.26% volume per volume does not seem reasonable for a porter. Porters are dark, top fermented beers made with generous amounts of hops. The typical porter alcohol level is in the range of 4.5% to 6% by volume. Therefore, the brewed chocolate porter has a significantly lower alcohol level than a theoretical porter.

Figure 3: Calibration curve of absorbance vs yeast cell count

ReferencesAmerican Society of Brewing Chemists. (1975). Apparent extract. Retrieved fromhttp://methods.asbcnet.org/methods/Beer-3.pdf

American Society of Brewing Chemists. (2002). Color.Retrieved from http://methods.asbcnet.org/methods/Beer-10.pdf

American Society of Brewing Chemists. (2011). Miniature fermentation assay.Retrieved from http://methods.asbcnet.org/methods/Yeast-14.pdf

American Society of Brewing Chemists. (2010). Wort color and sample preparation.Retrieved from http://methods.asbcnet.org/methods/Wort-9.pdf

Briggs, D. E., Boulton, C. A., Brookes, P. A. & Stevens, R. (2004). Brewing science and practice. Cambridge, EN: Woodhead Publishing Ltd.

Cutaia, A. J., Reid, A. J. & Speers, R. A. (2009). Examination of the relationships between original, real and apparent extracts, and alcohol in pilot plant and commerciallyproduced beers. Journal of the Institute of Brewing, 115(4), 318-327.

European Brewery Convention. (2000). Extract of malt: Congress mash. Retrieved fromhttp://analytica-ebc.com/index.php?mod=contents&method=297

Oliver, G. (2012). The Oxford Companion to Beer. New York, NY: Oxford University Press, Inc.

Appendix A Task Allocations

Mash CrewBoil Fermentation Crew

AnalysisJake Steinburg and Matt GillisDylan Walker and Riley Giffen

TransferMatt M and Andrea NeyensJonathan Totten and Matt Zwicker

Clean Up Crew

Po-Lin Hsu and Tianlin Zhao

Post Analysis Crew

9:00 amParker McNeil and Bonnie Moore

1:30 pmAnnmarie Hessian

5:00 pmSai Kalyanaraman and Vitor Motta

Appendix B Raw DataTestMash first halfMash End

IodineBlack (No change)Yellow (Change)

TestMash first halfMash End

Colour (Abs430)2.4382.261*

2.7252.221*

2.7422.19*

TestMash first halfMash End

Density (Plato)5.79.1

5.49.3

5.49.2

Date/TimeFerm TimeReadings (Triplicate)

Density (Plato)(4:40 pm 29-10-15)09.59.310.2

(9:00 am 30-10-15)16.3335.25.35.2

(1:30 pm 30-10-15)20.8333.83.63.6

(5:00 pm 30-10-15)24.3333.73.53.4

(10:45 am 2-11-15)90.0833.63.63.6

Cell counts (cells/mL)Date/TimeFerm TimeCell count (cells/mL)

(4:40 pm 29-10-15)0 hrN/A

(9:00 am 30-10-15)16.333 hr1.39 x 10^7

(1:30 pm 30-10-15)20.833 hr3.6 x 10^7

(5:00 pm 30-10-15)24.333 hr6.2 x 10^7

(10:45 am 2-11-15)90.083 hr1.4 x 10^7

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