How cider is made

The fruit determines the ceiling. Cider apples are picked or shaken down in autumn, later than dessert fruit, and unlike dessert fruit they are usually allowed to fall rather than being picked from the tree — bruising does not matter when the fruit is going to be crushed. Ripeness is judged by taste, by the starch-iodine test, or simply by the fruit coming away when the tree is shaken.

In several traditions the fruit is then left in a heap to sweat for days or weeks. Remaining starch converts to sugar, the flesh softens so it presses more easily, and some water is lost, concentrating what is left. In others, particularly where the aim is a fresh, aromatic cider, the fruit goes to the mill as soon as possible.

Fruit is washed and sorted before milling. Removing rotten fruit is not fastidiousness: mouldy apples introduce patulin and off-flavours that no later stage will remove.

Whole apples cannot be pressed — the flesh is too firm and the juice too well held. The fruit is first milled into pomace, a coarse pulp, by a scratter, a mill or a hammer mill. How finely it is milled matters: finer pomace releases more juice but can turn to a paste that blocks the press.

The pomace may then be left to stand for a few hours before pressing. This maceration extracts more colour and more tannin from the skins, and it lets enzymes begin breaking down the pectin that holds the juice in the cell walls. It also exposes the pulp to air, which browns it — an oxidation that is deliberate in most traditional practice and avoided where a pale, fresh cider is wanted.

Pressing then separates juice from solids. The traditional method builds the pomace into a stack of cloth-wrapped layers — a cheese — and squeezes it slowly; modern equipment uses hydraulic packs, inflatable bladders, belts or twin screws. The choice affects yield, how much air the juice sees, and how much fine solid ends up in the vat.

The juice is transferred to a vessel and fermentation begins, either spontaneously from the yeast already present on fruit and equipment, or from a cultured yeast added deliberately. Spontaneous ferments start with a succession of non-Saccharomyces yeasts and are taken over by Saccharomyces cerevisiae as the alcohol rises; an inoculated ferment skips most of that.

Temperature is the main lever. A cool, slow ferment preserves fruit aroma and produces fewer harsh higher alcohols; a warm one is faster and pushes the flavour towards fermentation-derived esters. Traditional practice ferments in an unheated building through the winter, which produces a slow ferment by default.

Some juices are deliberately handled to make fermentation slow and incomplete. Keeving, in the French tradition, strips nutrients from the juice before fermentation so that it starves gently to a halt with sugar still in it. Elsewhere the same end is reached by chilling, racking, filtering or, in commercial practice, by fermenting dry and adding sweetness back.

Once the vigorous ferment finishes, the cider is racked — drawn off the thick yeast sediment into a clean vessel. Left on heavy lees, it will pick up sulphidic and autolytic flavours; racked repeatedly, it clarifies and settles. Many producers then allow malolactic fermentation, in which lactic bacteria convert sharp malic acid into softer lactic acid, changing both the acidity and the aroma.

Maturation may run for a few weeks or a few years, in stainless steel, plastic, concrete, glass or wood. Wood contributes flavour if the barrel is new and mostly contributes slow oxygen ingress if it is old, which is what most cider barrels are.

Almost all cider is then blended. Batches from different varieties, different vats and sometimes different years are combined to reach a target, which is both a quality decision and a consistency one. After blending come the adjustments: sweetening, acid correction, filtration, sulphiting, and the decision about carbonation.

Cider becomes fizzy in one of three ways. It can be bottled or kegged before fermentation has finished, so the remaining ferment produces carbon dioxide in a sealed container. It can be bottled dry with a measured dose of sugar and yeast, which is bottle conditioning. Or the gas can be dissolved into it under pressure, which is forced carbonation and by far the most common industrial route.

Packaging then decides how long the cider stays as it is. Sterile filtration or pasteurisation prevents refermentation and microbial change; sulphite protects against oxidation and spoilage; a crown cap, cork or can each admit oxygen at different rates. A cider intended to be drunk within months and one intended to age are handled quite differently at this point.