Brewing Beer
The Brewing Process utilizes water, malted barley, and hops to create “Bitter Wort”. Bitter Wort is the base of beer before fermentation. The equipment consists of a Roller Mill , Hot Liquor Tank, Mash Tun, Brew Kettle and Heat Exchanger. The Roller Mill grinds the malt into grist, grist is malt or other grain that is cracked into 6 or 8 pieces separating the shell from the core. The Hot Liquor Tank is a vessel in which water is treated with salts and minerals, and heated to a temperature between 165 to 175 degrees Fahrenheit and will provide the hot brewing liquor for the brew. The Mash Tun is a vessel with a screened false bottom in which the ground malt and hot brewing liquor are mixed to create sweet wort. The Brew Kettle is a steam heated or gas fired vessel that boils the sweet wort from the mash tun. During the boil hops are added for hop bitterness, hop aroma and hop flavor changing the sweet wort to bitter wort. After the boil the bitter wort is ran through a Heat Exchanger to cool it down from boil temperature to room temperature, around 68 degrees Fahrenheit. From the heat exchanger the bitter wort flows directly to the Fermentation Vessel at which time the yeast is added to start the fermentation process.
The Brewing Process begins the day before to heat and treat the brewing liquor so it may be at the proper temperature for the brew. The brew day will start off with the brewer weighing out the proper amount of malt for the beer to be brewed. The amount and type of malt will very from beer to beer. These malts will determine the color, mouth-feel, sweetness and malt flavors such as roasted, chocolate, caramel, toffee, and so on. They will also contribute all of the fermentable and none fermentable sugars, the more malt the more sugars the more alcohol, more on that later.
The malt is then sent through the Roller Mill to be milled to grist. The malt is loaded into the malt hopper and will slowly drop in-between the rollers that are turning at a high rate of speed. As the malt drops, the rollers will crack the malt into a grist breaking it into 6 or 8 pieces and separating the shell from the core. From there it drops to the auger where it is sent directly to the mash tun or a grist hopper.
In the Mash Tun the brewer will add a layer of base brewing liquor to the mash tun approximately one inch above the screened false bottom to prevent the grist malt from getting in-between the screen and clogging it up. Then the brewer will mix the grist malt and hot brewing liquor at a determined rate to ensure proper hydration of the grist malt and to reach and not exceed the target temperature of the mash, the mixture of the grist malt and hot liquor at the point it is in the mash tun is called a mash or mash bed.
The targeted temperature of the mash can very from beer to beer but it will average around 150 degree Fahrenheit. This temperature is optimal for the best conversion of starches into sugars. Do you remember back in the malting process when the barley kernel created enzymes to turn the core into a food sores for itself, well we are now reactivating those enzymes and forcing them to work overtime to take all the free starches and break them up into sugars which in turn will be converted into alcohol during the fermentation process. To get full conversion of all the free starches it typically takes about an hour. During this time the sugars will blend with the brewing liquor creating a “sugar water” or sweet wort.
After conversion the brewer will begin to re-circulate through the use of a pump from the bottom of the mash tun up and back over the top of the mash bed. This process ensures that the sweet wort is clear and free of small partials of grist malt. Because of the course grind on the malt the sweet wort will easily pass by the grist malt as it drains out through the bottom of the mash tun essentially creating a filter bed separating the sweet wort from the grist malt which at this point is known as spent grain.
At the point the sweet wort is clarified from recirculation the brewer will transfer the sweet wort from the mash tun to the brew kettle. As this is being done the level of the sweet wort in the mash tun will drop and the brewer will begin sparging the mash bed with more hot brewing liquor. The sparging will help in keeping an even drain between the mash tun and the brew kettle and also will ensure that all of the sweet wort is leached from the spent grain to ensure a maximum yield. In conjunction with the sparge the brew kettle will be “fired” to raise the temperature of the sweet wort to a boil.
In the brew kettle the average boil time is about an hour. During boil time the sweet wort will be sterilized by the heat of the boil, compounds that are natural to the malt but impede the beers shelf life are boiled off and hops are added to impart the bitterness, aroma and flavor of the hop. At the point that the hops are added to the boil the sweet wort is know as “Bitter Wort” .
After the boil the steam or gas fire is turned off and the hops are let to settle to the bottom of the kettle. After the hops are settled the bitter wort is transferred through the heat exchange and into a sterile fermentation vessel. The operation of the heat exchanger is quite simple and it resembles the radiator on your vehicle. The heat exchanger is a set of stainless steel plate that are pressed tightly together. On one side of the plate will run the hot bitter wort and on the other side of the plate cold water will run in the opposite direction and the two will exchange heat, the bitter wort will cool down to room temperature while the water will heat upwards to 140 to 150 degrees Fahrenheit. The bitter wort will flow into the sterile fermentation vessel and the hot water will be stored in the hot liquor tank for the next brew.
During this transfer of the bitter wort from the brew kettle to the sterile fermentation vessel the yeast is added in, this is know as “pitching the yeast”. At the point the yeast is pitch the bitter wort is know known as beer because it has all the main elements of beer, water, malt, hops and yeast.
Almost immediately the yeast will begin to take in sugars and nutrient s from its environment yet the evidence of this may not be notice for up to 12 hours after pitching. As mention earlier the yeast intakes sugars and nutrients to produce cell material, the byproducts of this are carbon dioxide, alcohol and compounds that enhance and add to the flavor of the beer. Fermentation is exothermic and can create a lot of heat but the yeast performs best when temperature are controlled. This is done by the use of cooling a jacket around the fermentation vessel this jacket is controlled by devices that help regulate the temperature for a steady fermentation temperature.
Fermentation will begin to taper off as the yeast runs out of consumable sugars, this will occur within 5 to 12 day depending on the type of beer, fermentation temperature and the amount of original consumable sugars. When the time is right, determined by the brewer, the temperature of the fermentation vessel will be lowered to around 40 degrees Fahrenheit to put the yeast in a dormant stage to stop fermentation and let the yeast settle to the bottom of the vessel. This stage can last for weeks, or months, depending on the type of beer but typically this may last for a few days to a week. After which the beer is filtered and carbonated or sent directly to packaging or serving, again, depending on the type of beer and the brewer’s desire.