27.4 Beer and cider

What beer is made from

People have brewed beer for 6,000 to 8,000 years. It needs four things: malted barley, water, hops and yeast. Beer can be made from other grains, but many people define it as fermented barley. Germany's beer purity law of 1516, the Reinheitsgebot, allowed only those four ingredients.

A barley grain is the fruit of the barley grass. Most of it is the endosperm, a store of starch meant to feed the young plant, wrapped with the embryo inside a protective husk. Yeast cannot use that starch as it is.

Malting

Malting unlocks the sugar.

• Steeping. The grain is soaked, which wakes it, and it sprouts for 4 to 5 days. As the young plant grows, its enzymes start to break down the starch and the cell walls around it.
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• Kilning. Heat stops the sprouting and the enzyme work. The enzymes must survive, though, because they are needed later in the mash.
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How the malt is kilned sets much of a beer's color and taste. Higher heat brings Maillard browning and more complex flavor.

Kilned malts.

Most breweries buy their malt ready-made. A malt is called diastatic when it still has enough enzyme, such as amylase, to turn its own starch into sugar in the mash. Darker roasts give more chocolate, coffee, caramel and toasted flavors.

Brewing

• Milling. The malt is cracked into a coarse flour called grist. Brewers once kept it coarse, because the husks served as the filter. With plastic (polypropylene) filters, modern brewers can mill it smaller.
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• Mashing. The grist is steeped in hot water. This wets the grain, wakes the enzymes and turns the starch into sugar. The sweet liquid is the wort. Each enzyme works best in its own temperature range, from about 95°F up to 162°F.
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• Separating. The wort is drained off the husks and grain bits.
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• Boiling. Hops go in and the wort boils. The boil makes the hops bitter, drives off unwanted smells, kills bacteria and wild yeast, stops the grain enzymes, concentrates the wort, and makes proteins clump so they can be skimmed off with the hop debris. That sludge is the trub. Syrups or sugar from cane, beet or corn, called wort extenders, are usually added here.
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• Clarifying. Clumped proteins, tannins and hop remains are filtered out, each brewery in its own way.
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Hops

Hops are a climbing vine. Brewers use the flower cones, usually milled and pressed into pellets, or an extract. The alpha acids in hops change in the boil into iso-alpha acids, which give most beers their bitterness and also hold back some bacteria. Hops also bring tannins, the same drying compounds found in unripe fruit, red wine and tea.

India Pale Ale began with a problem of shipping. In the 1700s Britain kept a large army in India, and much of the ale shipped out spoiled on the way. Ales brewed with more hops kept better, and that was the start of IPA.

Hops added after the boil are dry hops, or aroma hops. Their oils, made of 400 to 1,000 different compounds, are strong in smell and flavor and would be lost in boiling. Light can turn the bitter acids into a smelly compound; such beer is called lightstruck or skunky. By hop type, amount and timing, a beer can smell of citrus, tropical fruit, flowers, herbs, spice, wood, pine or resin, among others, and hops also help the foam last.

Fermenting: ale and lager

The yeast decides the family a beer belongs to.

Ale and lager yeasts.

Both yeasts are now classed as strains of Saccharomyces cerevisiae. German wheat beers use their own weizen yeast, counted as an ale yeast. Beers left to wild yeast and bacteria are spontaneously fermented; Belgium's lambic beers, from West Flanders, are made this way with Brettanomyces, which can taste of barnyard or tropical fruit.

Fermentation makes flavor as well as alcohol.

• Fusel alcohols give a warming feel, but too much tastes harsh; fusel comes from the German for bad liquor. Too much yeast, or fermenting above 80°F, makes more of them.
• Esters bring fruit and flower notes: banana, apple, grape, papaya, honey or rose; some smell of solvent. Brewers want a balance, not a flood.
• Diacetyl tastes of butter. A little suits many ales; more is unpleasant, especially in lager, and can turn rancid. The yeast makes it early and clears most of it by the end. Some beers get a diacetyl rest: two or three days slightly warmer once fermenting is done.

Beer styles

There is no single agreed way to sort beers. Brewers describe them by yeast, malt, hops, strength and fizz. Alcohol runs from 2% to over 14%. Bubbles add smell, mouthfeel and taste and shape the foam. They may come from the yeast or be forced in under pressure. Nitrogen gives smaller bubbles and a softer feel than carbon dioxide.

Cider: the apples

Cider is made from apples. In the United States the word can mean plain apple juice or the fermented drink; here it means the alcoholic one. Apples themselves, and the difference between eating and cooking apples, are covered with fruit. see chapter 18: Pomes

The cider is only as good as its apples. They must be ripe, juicy and sweet, and a full-bodied cider mixes several kinds, sweet and tart, for balance. The apples are not peeled, because much of the taste is in the skin. They are ground, then pressed; most of the fiber stays behind. Pressed juice may be pasteurized and bottled as apple juice, or fermented.

The main sugars in the juice are fructose, glucose and sucrose. Glucose syrup and water cost less than juice, so many commercial ciders are now about 35% juice and 65% glucose syrup.

Cider: before and during fermenting

Pectin. Apples hold a lot of pectin. Left in, it can set into jelly when the juice is concentrated, or leave the cider hazy. Makers may add pectin-splitting enzymes before fermenting, after it, or both. French cider makers often clear the juice first with gelatin, a step called defecation, then ferment it slowly; these ciders are fruitier.

Sulfur. Many makers add sulfur dioxide or potassium metabisulphite. It stops most spoilage yeasts and bacteria but lets the wanted fermenting yeast work.

Yeast. Cider was once fermented by the yeasts and bacteria already on the apples. A wild ferment passes through three stages, each led by different yeasts: a fruit-yeast stage, a fermenting stage when strong Saccharomyces yeasts take over and make the alcohol, and a maturing stage. Large factories often sulfur heavily and add pure wine yeast instead; craft makers often keep the wild way.

Fermenting takes 5 to 10 days, or 4 to 6 weeks when cool. By then the yeast has eaten nearly all the sugar and gone quiet. The riper and sweeter the fruit, the more alcohol the cider ends with.

Esters give cider fruity, flowery notes, and ethyl acetate can be up to 90% of them. Compounds called dioxanes give the green, cidery taste, and they form only when apples or pears ferment.

Cider: after fermenting

• Racking moves the cider off its lees, the sediment, usually by filtering or spinning.
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• Aging was done in wooden barrels, which is not needed if the cider has been chilled and cleared well.
• Malolactic fermentation is a second ferment by lactic acid bacteria, often living in the barrel wood. They turn sharp malic acid, the taste of green apples, into softer, richer lactic acid. The cider ends rounder and less raw. High alcohol or a pH below about 3 to 4 holds it back.
• Dry or sweet. Cider is naturally dry: little sugar is left, and the taste comes from the alcohol, esters and the rest. Some drinkers want a sweet still cider.
• Sparkling. Carbon dioxide can be forced in under pressure before bottling or kegging. Or yeast is added at bottling so the cider makes its own bubbles; then a little yeast settles in every bottle and clouds the last pour. Bottles must be made to hold the pressure.
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• Stabilizing. At the end the cider is pasteurized, or else treated with ascorbic acid or sulfur dioxide. This also guards against Acetobacter, the bacteria that turn alcohol into vinegar.
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