The science of beer

October 19, 2017, Posted by megan

With breweries popping up all over Calgary, it was only a matter of time before one landed in Victoria Park. Mill Street Brewpub opened its doors in Calgary on October 20, 2016 – nearly one year ago. To celebrate this milestone, the BIA joined Mill Street’s Head Brewer, Bennie Dingemanse, in brewing the One Year Anniversary Pale Ale.

Unlike most breweries in Calgary, Mill Street is a national brand, with breweries also located in Toronto, Ottawa, and St. John’s. While Mill Street technically isn’t a local brewery, the beers made in the Calgary are for the local brewpub and can also be found at select growler bars in the city. Mill Street Classics, which are also found at the brewpub, are brewed in Toronto to allow Bennie to focus on brewing for Calgary.

We started the day with an overview of the equipment and some of the terms we would need to follow Bennie’s explanations (hot or cold liquor for hot or cold water, grist for milled malt, and mash for the mix of grist and hot liquor). This was only the beginning of the day’s vocabulary lessons.

Brewing typically begins with milling. The mill cracks the grain to expose the starches and protein-based enzymes of the malt. Bennie weighed and milled the malt the day prior, so we moved straight into step two - mashing. Mashing is the process used to break down the malt starch and proteins into the sugars and amino acids required for the fermentation process. This is achieved by mixing the milled malt with hot liquor – also called a mash. The process of starch degrading into sugar and proteins into amino acids is called conversion.

Mill Street

Calgary has hard water, which can cause some headaches in the brewing process. To combat the city’s hard water and to bring the pH to a level where a conversion can occur, we added gypsum and an acid to the mash. I quickly learned that making beer is science. We took the pH of the beer and used iodine to detect starches, which measures if conversion has occurred. Our iodine test came back negative. We retested – also negative. So, we used a hydrometer to measure the mash’s sugar content, in degrees Plato. Our results were within a reasonable range. We also tasted the mash and could taste its sweetness, which proved that conversion had occurred. When conversion is complete, you are left with a sugar solution called ‘wort’ and the husks and solids of the malted barley.  

Next, we moved to the lautering process, which works to separate the wort from the remaining husks and malt. The lauter tun, a vessel with a false bottom, helps separate the wort from the residual grains. By drawing wort from the bottom of the mash and adding it to the top, the husks and the false bottom filter unwanted mash debris and proteins from the wort.

It is in this process that we hit our second speed bump – stuck mash. This occurs when the wort does not drain into the kettle quick enough (or at all). In the year that Mill Street has been open, this is the first time Bennie has experienced stuck mash. The fix? We added rice hulls to the lauter tun, let it sit for fifteen minutes, stirred the mixture and then began the lautering process again.

Once the wort runs clear, it is returned to the brew kettle and sparging can begin. Sparging is the process of rinsing the grains to ensure as much of the remaining sugar is extracted as possible. In this case, we started sparging at the same rate that the wort was moving into the brew kettle.

Bottlecaps

After the wort is collected in the brew kettle, it is boiled for 60 minutes to sterilize the solution. Hops were added during the boiling process to provide bittering and aroma’s. We also added a fining product (Whirlfloc) to help clarify the wort. Mill Street’s fining agent is not animal derived (some finings are), which means that their beers are vegetarian and vegan friendly.

After the wort has boiled, it is moved to the whirlpool and the hops are added. For this recipe, we added three different hops. The whirlpool works to separate the coagulated protein and left over hop material from the wort. After the whirlpool the wort is run through a heat exchanger to cool down the wort. If yeast was added to the wort at a high temperature, it would die – making this an important step.

Finally, once the wort has cooled down to a reasonable temperature, we moved onto fermentation. Sterile oxygen and then yeast is added to the wort. The yeast uses the oxygen, which permits the yeast to multiply up to five times. When the oxygen is gone, the yeast begins to ferment the sugars and amino acids. The process of the yeast metabolizing the sugars and amino acid from the wort is what produces the alcohol we all know and love in our beer!

It is the brewmaster’s job to ensure that they create the perfect environment for yeast to thrive in. Sanitation and fermentation are both key parts in creating the perfect environment, and Bennie believes that they are the most important parts of the brewing process.

Before heading back to the office, we had a quick chat with Cam Carter, Mill Street Calgary’s General Manager. He described Mill Street as, “a local brewery making regional beers for the community.” Cam would, “love to see the city grow and expand” and likes that Victoria Park, “is a self-sufficient community.” It is a place that has, “people living here, entertainment, restaurants and night life” and of course a, “mixture of new and old, with high rises and historical homes.”

The only thing left for us to do was wait. Unfortunately, beer is not made in a day or overnight. The time it takes for a beer to ferment is dependent on the type of beer being made. You can bet that we will be headed to Mill Street on October 20 to test the One Year Anniversary beer to try the beer that we helped Bennie make!