In other cases, the hot wort can be transferred to a coolship , sometimes spelled koelschip. This is a shallow tub that allows the liquid to be exposed to the open air.
As the wort cools in this vessel, it reacts with ambient yeast that kickstarts the brewing process. After about a day the beer is transferred to another vessel, like a barrel, foudre or stainless steel fermentation vessel.
There are two main types of fermentation vessels. Horizontal tanks are most often used for lagers, while conical fermenters, which stand upright, favor ales. These, as well as brew kettles, are measured in volume by the barrel, where a standard barrel of beer is 31 gallons. Larger breweries will have fermentation tanks that are many hundreds of barrels in size.
Smaller breweries can use vessels that hold just half a barrel. Yeast is added to the fermentation vessels to begin the process of converting the sugars of the wort into alcohol, while also releasing CO2.
There are many different yeast strains that can impart a wide variety of flavors and aromas. Certain beer styles also rely on a specific type of yeast to achieve a desired outcome. Fermentation can take a matter of days for some ales, though will typically go on for many weeks when lagers are being made. Some can even be left for a year or longer when making big boozy beers, like an imperial stout aged in Bourbon barrels. After fermentation is complete, many beers are filtered or run through a centrifuge to remove any particulates.
One package of yeast is enough to ferment 5 gallons 19 l of beer. The best thing is that you can use the same strain for many generations without purchasing the new one. Most breweries use the same yeast strain many times, even for brewing different beer batches. Some of them purchase yeast from reputable suppliers, while large breweries produce their own pure yeast strains. There are hundreds of yeast species in nature, but breweries use particular cultivated strains to keep the fermentation process under control.
You can recognize three primary beer yeast types that belong to a Saccharomyces family, including:. Beer brewers used Saccharomyces Cerevisiae in the 19th century but slowly switched to bottom-fermenting yeast over time. Nowadays, top-fermented ale beer is trendy again. This yeast grows well and can be active in a wide temperature range, from 65 to 75 F 18 — 24 C.
That makes it an ideal solution for homebrewers that make this beverage without special equipment. Thanks to the high production of esters and phenols during fermentation , this yeast kind will help you get a full, complex beer with spicy or fruity flavors. Since each yeast variety produces specific esters, brewers often choose unique strains to get their own beer brand.
The best temperature for the initial fermentation while using this yeast type is about 50 F 10 C , while the lagering period afterward requires 40 F 4. During the fermentation process , it sinks to the yeast tank bottom. Thanks to this yeast, you can get a clean, superbly crisp beer with higher malt and hops tone. You need a temperature-controlled fridge to achieve this. Be prepared that the fermentation process lasts twice as long as ales.
This yeast type was considered an undesired contaminant for an extended period. Nowadays, some brewers cultivate it for beer production. Brettanomyces Brett yeast is the most popular, but only true masters can control its participation level in the beer production process. There would be no beer without malted grains. In most cases, breweries use barley, but you can make beer of wheat, oats, rye, rice, and corn, as well.
Since barley provides more sugar, you will use it as a base and optionally add other grains to get a particular beer flavor and character. Boiling comes next, which sees a very high temperature boil get rid of remaining enzymes and oxygen and stabilise the wort ready for the hops.
Adding the hops is where the beer really gets its character. There's a wide variety, and brewers are constantly trying new combinations. Hops add bitterness to balance out the sugar from the wort, and they act as a natural preservative, too.
Fermentation is a two-part process. With fermentation complete, the final gravity reading is taken and compared with the first to work out the final alcoholic content. Then the beer is bottled, canned or kegged and soon to be enjoyed, after a final conditioning period of at least two weeks. It is during this conditioning stage that some beers are left to naturally carbonate.
Of course, there are many ways to tweak this process and many brewers do, giving us the wide range of styles we enjoy today. Many of these differences are historic. Belgium , for example, is known for strong Trappist beers, originally brewed in monasteries and with high alcoholic content. While Germany , just across the border, is the home of lager and well known for its wheat beers.
This makes it very difficult to write an article that explains every possible process in full.
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