Brewing begins with raw barley, wheat, oats or rye that have been force germinated in a malt house. The grains held in huge barns, have been fooled into thinking they are underground and it is springtime by controlling the environments temperature, moisture and light. The germinated grain is then dried in a kiln and sometimes roasted then sent through a grist mill, cracking open the husks of the kernels, which helps expose the starches for extraction during the mashing process (below). The mixture of different types of grain used by our brewer is known as the grist bill (our recipe).
The first step in the beer-making process is mashing, in which the grist (milled malt), is transferred to our mash tun. Mashing is the process of combining the grist and hot water, known as hot liquor, and soaking in temperatures usually between 60 – 70 Celsius. Mashing causes the natural enzymes in the malt to break down starches, converting them to sugars, which will eventually become alcohol. This process takes place over an hour or two. Mash temperatures can be gradually increased or allowed to rest at certain temperatures, choices which are very much part of the brewer’s art. Different temperature levels activate different enzymes and affect the release of proteins and fermentable sugars. Proteins play a smaller role but are important to the creation of foam in a finished beer.
After the mashing process is complete, the grains, water and sugar are still in suspension in the mash tun. The sugars are separated from the grains in a process called sparging (which is a bit like rinsing). The mash tun has a false bottom that is a fine mesh. This allows our brewer to draw liquid from the bottom of the grain bed. Hot water at 60-70c is sprayed over to the top of the grain bed, run through the bed, and drawn off the bottom through the false bottom and out the boiling vessel. This extracts sugars from the grains and produces sweet liquid called wort for boiling. The initial runnings (first few gallons) drawn during the sparge process are recirculated back through the grain bed, as the early runnings often contain grain husks, crushed material and other undesirable elements. After the initial runnings, the grain bed will act as a filter and reduce the cloudiness of the runnings. Sparging is best done slowly so that a maximum amount of sugar can be extracted from the spent grains. This sparge wort is then sent to our copper for boiling.
The boiling process takes place in our copper (big kettle). Where the sweet wort produced by mashing and sparging, is boiled for an 1-2 hours, adding hops at various stages along the way. Bittering hops added early. Aromatic hops added late. Boiling hops releases critical alpha acids that bitter the beer to offset the sweetness of the malt. The longer hops are boiled, the more bitterness they will release. The boiling also sterilises the beer and kills any bacteria present. This hopped wort is then rapidly cooled and transferred to fermenting vessels.
Wort is transferred to a fermentation tank and yeast is added (pitched). Ale yeast rises to the top of the wort and lager yeast generally collects in the bottom. This stage is the primary fermentation — the conversion of sugars to alcohol and carbon dioxide that lead to an ale or a lager, depending on the type of yeast used.
Once yeast has been pitched at proper temperature, the beer is maintained at 13-21 Celsius for ales, and 4-12 Celsius for lagers. The process of the yeast converting sugars to alcohol generates heat and is monitored closely our brewer. The higher temperatures employed for ale yeast result in more esters, or fragrant organic compounds.
During the conditioning process for ales and lagers, the beer will mature and smooth, and by-products of fermentation will diminish. It is possible to dry hop during this stage for added aroma, and other methods such as barrel aging can further introduce complexity.
The cold storage of beer for 30 days known as lagering is a key difference in the cleaner nature and more defined flavors of lagers when compared to ale.
The conditioning process can last from one to six weeks and sometimes more. Depending on the style, brewers may choose to filter any remaining yeast or other particles from the beer and then store it in bright tanks. Some pasteurize their beer to improve clarity and shelf life.
Once the beer has fermented, it is packaged into casks or kegs.
The beer is then carbonated, either naturally or by force. Cask beer is naturally carbonated by feeding the existing yeast in the beer in a sealed cask (they naturally produce CO2). Kegged beer is force carbonated by adding CO2 gas to a keg under high pressure, forcing it to be absorbed into the beer.