Home brewing beer uses many of the same processes utilized by commercial breweries. With a basic understanding of each step in the process, the home brewer can make the best beer possible with their available equipment.
Grinding Malt for the Home Brewer
For the home brewer, the beer making process begins by grinding the malt from the grain bill. Most home brewing supply shops will grind grain for customers, saving people time for more important things, like brewing beer. For those who insist on grinding their own grain, care must be taken not to grind the grain too finely, or too coarsely.
Grain ground too finely will chop up the husks, increasing the likelihood of a stuck mash. Too coarse of a grind will expose too little of the starches to the mash water leading to an inefficient mash with lots of fermentable sugars being thrown out with the spent grist.
Mashing in the Home Brewery
Mashing is the process by which non-fermentable starches in the malt are converted to fermentable sugars. Most malt types contain diastatic enzymes which do the conversion when exposed to water in the temperature range of 144 to 158 degrees Fahrenheit. The mash temperature determines whether the resulting beer will be light or heavy in body, and to a smaller degree, how sweet the beer will be.
The grains are soaked in a temperature controlled vessel called the mash tun at the correct temperature until all of the starches have been converted to sugars.
Home Brew Sparging
When mashing is complete, the temperature in the mash tun is raised to 170 degrees Fahrenheit stopping the enzymatic process. Commercial breweries have separate vessels for mashing and lautering, or rinsing the sugar from the spent grain, but most home brewers combine those functions in a single vessel.
Water is added to the top of the grain bed in the mash tun while simultaneously draining the liquid from the bottom of the mash tun into the brew pot. The grain bed compresses forming a filter, which allows the diluted sugar and water mixture through, while leaving behind the grain. This process continues until all, or as much as possible, of the sugars in the grain bed have been extracted.
Boiling Home Brew Wort
Once the sugar water mixture, known as wort, leaves the mash tun, it is transferred into a boiling kettle. Here hops will be added to the wort during the boiling process balancing out the sweetness of the malt with bitterness and the spicy flavor and aroma of the hops. Boiling the wort sterilizes it in preparation for the addition of yeast, as well as modulates the sugar concentration by boiling off excess water. Once the boil is complete, the wort is moved into a fermentation vessel leaving behind any hop residue before cooling it to below 70 degrees Fahrenheit.
Home Brewery Fermentation
Yeast is added to the cooled, sterilized wort and the fermentation process begins. Over the next 10 to 14 days, the yeast will convert the fermentable sugars in the wort into alcohol and carbon dioxide. After fermentation, most commercial breweries transfer the beer, which at this point is not carbonated, into a bright beer tank where the beer is filtered at low temperatures to produce crystal clear beer. Most home brewers do not cold-filter because it only effects the appearance of the beer and can negatively effect the flavor of the beer.
Bottling the Home Brew
Commercial breweries store the beer in temperature controlled tanks pressurized by carbon dioxide to carbonate the beer. The carbonated beer is then bottled at very low temperatures to keep the carbon dioxide dissolved in the beer.
Home brewers who bottle their beer, as opposed to those with draft beer equipment, usually bottle non-carbonated beer with additional priming sugar and allow the yeast to naturally carbonate the beer in the bottle over the course of several weeks.