Crafting Beer: A Journey Through History, Science, and Flavor

The short answer: beer is made from four ingredients: malted grain for sugar, colour and body, hops for bitterness and aroma, water, and yeast, which turns the sugar into alcohol and CO₂ and adds its own flavours. People have brewed grain-based drinks for thousands of years; hops became standard in Europe in the Middle Ages, and lager, IPA and today’s craft styles followed.

Ingredient	What it gives	Guide
Malt	Fermentable sugar, colour, body	Choosing malts
Hops	Bitterness, aroma, stability	Bitterness vs hoppiness
Water	Over 90% of the beer; minerals shape flavour	Water chemistry
Yeast	Alcohol, CO₂, fruity and spicy notes	How yeast make beer

How beer is made

Step	What happens	Typical numbers
Mill	Crack the malt so water can reach the starch	Crushed, not powdered
Mash	Soak the grain in hot water; the malt’s own enzymes turn starch into sugar	148–158°F (64–70°C), about 60 minutes
Lauter and sparge	Drain the sweet liquid (wort) and rinse the grain	Sparge water about 168°F (76°C)
Boil	Add hops; the boil sanitizes the wort, turns hop acids bitter and drives off unwanted aromas	Usually 60 minutes
Chill	Cool the wort quickly to yeast temperature	As fast as you can
Ferment	Yeast turn sugar into alcohol and CO₂	Ales 60–72°F (16–22°C), 1–2 weeks; lagers 48–55°F (9–13°C), then weeks near freezing
Package	Carbonate in bottles with a little sugar, or in a keg with CO₂	Many styles about 2.2–2.7 volumes of CO₂

Each step has its own guide: start with the brewing process step by step.

Where the flavour comes from

• Malt. Base malts such as pale, Pilsner and Munich taste of bread and crackers. Crystal (caramel) malts add caramel, toffee and body. Roasted malts add coffee, chocolate and dark colour. Those flavours are made at the maltings, by kilning and roasting.
• Hops. Hops boiled for an hour give bitterness, because their alpha acids only become bitter in the boil. Hops added late, in the whirlpool or as a dry hop give flavour and aroma with little bitterness. Varieties differ: Cascade is citrus and floral, Saaz spicy and herbal. Hops also help keep beer from spoiling.
• Yeast. Ale yeast works warm and gives fruity esters; some strains add clove (hefeweizen) or pepper (saison). Lager yeast works cool and tastes clean. See ale vs lager fermentation.
• Water. Sulfate makes hop bitterness drier and crisper; chloride makes malt taste rounder and fuller. Local water shaped classic styles: Burton’s hard water suited pale ales, and Plzeň’s very soft water suited pale lager.

A short history of beer

When	What happened
About 3500 BCE	Jars at Godin Tepe, in western Iran, hold some of the earliest chemical traces of barley beer
About 1800 BCE	The Sumerian Hymn to Ninkasi, goddess of beer, describes brewing
1100s	Hildegard of Bingen writes that hops keep beer from spoiling; hops spread through European brewing over the following centuries
1516	Bavaria’s purity law limits beer to water, barley and hops
1842	Plzeň brews the first golden Pilsner lager
1883	Emil Christian Hansen at Carlsberg grows the first pure culture of lager yeast

The purity law leaves out yeast because its role wasn’t understood until the 1800s. The story of IPA is in our history of IPA.

Reading a beer’s numbers

• ABV: alcohol by volume. Most beers sit around 4–7%.
• OG and FG: original and final gravity, the sugar before and after fermentation. The gap tells you the ABV.
• IBU: bitterness. See IBU explained.
• SRM or EBC: colour, from straw to black.

Style guidelines set ranges for each of these; see our guide to the BJCP style guidelines.

Brewing it yourself

You can start with malt extract, which skips the mash, or brew all-grain from malt, which gives you full control (see extract vs all-grain). A single-vessel electric system such as the Unibräu does the mash, sparge and boil in one kettle. Pick a forgiving first beer from our beginner-friendly styles or our recipes.

Frequently asked questions

Is beer always made from barley?

Barley is the main grain almost everywhere because it malts well and carries the enzymes needed in the mash. Wheat, oats, rye, corn and rice are common additions, and gluten-free beers use grains such as sorghum or millet.

What’s the difference between ale and lager?

The yeast. Ale yeast ferments warm and gives fruitier beer; lager yeast ferments cool and gives cleaner beer, then the beer is aged cold.

How long does it take to make beer?

A brew day takes a few hours. An ale is usually ready to drink about three to four weeks later; a lager takes longer because of its cold aging.

Why does beer need hops?

Bitterness to balance the malt’s sweetness, aroma, and protection from spoilage. Before hops, brewers used other herbs for the same jobs.

Related guides

The brewing process step by step, history of IPA, ale vs lager, extract vs all-grain, beginner-friendly beers.