How Beer Is Made

From Grain to Glass

Brewing beer is both a science and a craft. While recipes and techniques vary enormously, every beer follows the same fundamental process. This guide walks through each stage.

Step 1: Milling

The process begins by crushing malted grain through a grain mill. The goal is to crack the husk open and expose the starchy endosperm without pulverizing it into flour. A good crush improves sugar extraction during the mash while keeping the husk intact for filtration during {{glossary:lautering}}.

Step 2: Mashing

Crushed grain is mixed with hot water in a vessel called a mash tun. The brewer holds the mixture at specific temperatures — typically 148-158 F (64-70 C) — for 60 minutes. At these temperatures, enzymes (primarily alpha-amylase and beta-amylase) convert grain starch into fermentable sugars.

Lower mash temperatures favor beta-amylase, producing more fermentable {{glossary:wort}} and a drier, lighter-bodied beer. Higher temperatures favor alpha-amylase, creating more unfermentable dextrins for a fuller body.

Step 3: Lautering and Sparging

After the mash, the liquid wort must be separated from the spent grain. The grain bed itself acts as a natural filter. The brewer recirculates the first runnings (vorlauf) until they clear, then drains the wort to the kettle.

{{glossary:sparging}} — rinsing the grain bed with additional hot water — extracts residual sugars and improves brewing efficiency. Fly sparging continuously sprinkles water over the bed, while batch sparging drains and refills in discrete steps.

Step 4: The Boil

Wort is brought to a vigorous rolling {{glossary:boil}} for 60-90 minutes. Boiling achieves several critical goals: it sterilizes the wort, isomerizes hop alpha acids for bitterness, drives off undesirable volatile compounds like DMS, concentrates the wort, and causes proteins to coagulate.

Hops are added at various times during the boil. Bittering additions go in early. Flavor and aroma additions go in during the last 15 minutes or at flame-out.

Step 5: Cooling

After the boil, wort must be cooled rapidly to fermentation temperature — typically 65-70 F for ales or 48-55 F for lagers. Rapid cooling minimizes the risk of contamination and reduces the formation of DMS. Most brewers use a wort chiller (immersion, counterflow, or plate).

Step 6: Fermentation

Cooled wort is transferred to a sanitized fermenter and pitched with yeast. Over the next 3-14 days, yeast consumes sugars and produces alcohol, CO2, and flavor compounds. Temperature control during fermentation is one of the most impactful variables in beer quality.

Step 7: Conditioning

After primary fermentation, beer is conditioned — either in the same vessel or transferred to a secondary. Conditioning allows residual yeast to clean up off-flavor compounds like {{glossary:diacetyl}} and acetaldehyde. Lagers undergo cold conditioning (lagering) near freezing for weeks to months.

Step 8: Packaging

Finished beer is carbonated (force carbonation in kegs or natural carbonation in bottles) and packaged. Minimizing oxygen exposure during packaging is essential to prevent staling and oxidation.