How beer is made

Brewers first turn barley into a sweet porridge, then let yeast eat the sugar and leave alcohol and bubbles behind.

stations: 8
things upstream: 59
raw sources: 22
steps from the ground: 9

The short version

Beer begins with malted barley, grain that has been soaked, sprouted and kiln-dried. Malt is milled and steeped in hot water, where enzymes turn its starch into sugar. The sweet liquid, called wort, is boiled with hops, cooled, and fed to yeast. The yeast produces alcohol and carbon dioxide, and the beer is matured, filtered and packaged.

Sprout and kiln barley

Barley is soaked in water, spread out to germinate, then dried in a kiln with gradually rising heat. The sprouting creates enzymes that will later turn starch into sugar. The finished grain is called malt.

about 40 hours of soaking, then 5 days of germination

Goes in
Barley
Mill and steep

Malt is crushed to expose the starchy core and mixed with hot water in a mash tun. Enzymes in the malt break the starch down into fermentable sugars. Brewers often add rice or corn as cheaper adjuncts.

60–70 °C for 1 to 2 hours

Goes in
Water Corn Rice Malted barley
Drain the sweet wort

Wort is strained through the bed of spent grain in a lauter tun. Hot water is sprayed over the grain to rinse out the remaining sugar. Animal feed is the usual fate of the grains left behind.
Boil with hops

The wort is boiled in a large kettle with hops. The boil sterilizes the liquid, stops the enzymes and extracts bitterness and aroma. A whirlpool afterward gathers the solid particles into a cone in the middle.

Goes in
Hops
Crash-cool the wort

A plate heat exchanger cools the hot wort fast. Yeast dies above 60 °C, so the liquid has to drop to a safe temperature before it goes into the fermenter.
Feed it to yeast

Yeast is added, or pitched, and begins to eat the sugars, producing alcohol and carbon dioxide. Ale yeast works warm, at 15 to 20 °C, while lager yeast works cooler, at around 10 °C.

ale: 15–20 °C; lager: about 10 °C

Goes in
Baker's yeast
Mature the beer

After fermentation the beer rests in a conditioning tank, from a week to several months. Rough flavors fade and the taste smooths out. Lagers are held near freezing for weeks.
Filter and package

The beer is filtered, carbonated to the right level and filled into bottles, cans or kegs. Brown glass bottles protect it from light.

Goes in
Glass bottle Aluminum can Carbon dioxide

End of the lineBeer

Worth repeating

Archaeological evidence of cereal-based brewing has been found in Raqefet Cave in present-day Israel.
Copper has long been the favored metal for brew kettles because bubbles do not cling to it, so it heats the wort evenly.
The Joseph Schlitz Brewing Company began using brown bottles in 1912 to protect beer from light.
A clear Sumerian prayer, the Hymn to Ninkasi, doubled as a way to remember the beer recipe.