Crushed malt is mixed with hot water to create a porridge consistency, called the mash. The mash is held at a temperature of between 149F and 158F, depending upon the brew. The mixture then sits for an hour in the first vessel, called the mash tun. Here the starches in the malt dissolve in the hot water and are converted to fermentable and non fermentable sugars. This is made possible by enzymes that are present in the malt before the mashing process. One of the enzymes, amylase, is also found in your saliva and is responsible for aiding in digestion and turning starchy foods sweet in your mouth.
After the mash has rested for an hour, the liquid in the mash is separated from the grain via a screen in the bottom of the first vessel. The sugar water is then pumped into the other vessel called the kettle. The screen allows the sugar water, called wort (sounds like wert), to be drawn off of the bottom of the vessel without drawing any grain with it. As the wort is run off into the kettle, hot water is run through the grain in the mash tun to rinse any sugars trapped in the grain. When the correct strength wort is collected in the kettle, the rinsing and running off is finished. The alcohol percentage of the finished beer is dependent upon the strength of the wort collected during this step.
The wort in the kettle is then boiled with direct flame from underneath. As the wort is boiling, hops are added at various times throughout the 60 to 75 minute boiling time. Depending upon when the hops are added changes the affect of the hops from hop bitterness, to hop flavor and then finally to hop aroma.
Once the wort has been boiled it is time to whirlpool it. The liquid is spun in the kettle for ten minutes. This spinning forces all of the hops and proteins formed in the boil to come to the middle into a conical pile known as a trub pile (sounds like troob). The spinning liquid is then allowed to settle for fifteen minutes before pumping it into a fermenter.
The wort is then drawn from the side of the vessel (to avoid putting any trub into the fermentation vessel) and run through a heat exchanger which cools it from 212F to 65F instantly. The cooled wort is aerated with sterile air (yeast needs oxygen for the first part of their life cycle) and then pumped into a fermenter which has been “pitched” with brewer’s yeast. When the cooled aerated wort is pumped into the fermenter it is called the knockout.
After the cooled, aerated wort is introduced to the yeast in the fermenter, fermentation begins. First, the yeast uses the oxygen dissolved into the wort to reproduce. The yeast multiplies up to 5-7 times the initial amount “pitched” in the fermenter. After the period of multiplication, the yeast begins to eat and metabolize the sugars and nutrients in the wort. As the yeast eats the sugars it releases waste products. The waste products of a healthy yeast strain are ethanol (or alcohol), carbon dioxide, off flavors and heat. The liquid is kept at a constant temperature between 65F and 72F depending upon the brew. After the yeast has eaten all of the fermentable sugars it begins to drop out of the liquid solution. At this point the liquid has finally turned to beer. The beer is then cooled to just below 32F. The yeast is then removed from the fermenter and stored. This yeast will start the process over again when another batch of wort is brewed.
After the beer has been cooled, it is kept cold for a minimum period of one week and up to a period of many months. This allows the yeast to “clean up” the beer by re-absorbing off-flavors created during fermentation. After the yeast has re-absorbed the off flavors, it is time to filter it. The beer is pumped through filter sheets that strip the beer of any yeast and proteins left in suspension. While the beer is being filtered, carbon dioxide is pumped into the beer to raise the carbonation to drinkable levels. At this point beer has been created and a perfectly carbonated, bright beer is now available for drinking.