Sidra natural is the traditional cider of Asturias in northern Spain: dry, sharp, a little bitter and only faintly sparkling, poured from a height into a wide glass a little at a time. Under the protected designation of origin Sidra de Asturias, sidra natural is defined as the drink made by the total or partial alcoholic fermentation of fresh apples or their juice, following traditional practice, with no added sugar and with only its own carbon dioxide from fermentation; it must reach at least 5% alcohol (DOP Sidra de Asturias specification).
In 2024 UNESCO added Asturian cider culture to its list of the Intangible Cultural Heritage of Humanity, covering the whole process from planting apple trees to drinking the cider, including the way it’s poured (Turespaña).
The Apples and the Rules
Asturian cider orchards are always multi-varietal, the result of centuries of farmers selecting local seedling trees. The DOP sorts its permitted varieties into nine technological groups by acidity and phenolic (bitter, astringent) content – from sweet and bittersweet to sharp and bitter-sharp – and a cider blends several of them. Its other rules include a production area of 78 municipalities, pressing that extracts no more than 75% (fast presses) or 80% (slow presses) of the apples’ weight as juice, volatile acidity below 2.2 g/l, total sulphur dioxide below 150 mg/l, and slight natural sparkle: at least 0.5 atmospheres in the bottle, felt as a light prickle on the tongue (DOP specification).
The same document traces apple growing in Asturias to before the Roman conquest, describes the apple tree as part of the landscape from the 8th to the 10th centuries, and records contracts for planting orchards on another’s land between the 11th and 14th centuries.
What Ferments It
Traditional sidra is fermented by the yeasts that arrive on the apples and live in the cider house. In Asturian cider plants, Saccharomyces cerevisiae and the apiculate yeast Kloeckera apiculata were found in every fermentation studied (Cabranes et al., 1990). In a later study at an Asturian cellar, juice from traditional pressing always held Saccharomyces together with non-Saccharomyces yeasts; S. bayanus led the early and middle stages and S. cerevisiae took over at the end (Valles et al., 2007).
The DOP states that Asturian ciders always go through both alcoholic and malolactic fermentation (DOP specification), in which lactic acid bacteria turn sharp malic acid into softer lactic acid. In Asturian cellars the bacteria doing it were Lactobacillus brevis and Oenococcus oeni, with O. oeni the more effective (Sánchez et al., 2012). Some cider bacteria can also make biogenic amines such as histamine, and amine levels in natural ciders from Spain and France varied with their origin (Ladero et al., 2011).
Pouring: Escanciado
Sidra is poured by the escanciador, who holds the bottle high above the head and the glass low and tilted, so a thin stream strikes the inside of the glass. The splash wakes up the cider’s light natural gas and aroma. Only a small amount – a culín – is poured at a time and drunk straight away, before it settles. Electric pourers do the same job at home.
Making Cider at Home
Outside Asturias you won’t have its varieties, but you can make a dry, wild-fermented cider in the same spirit with a blend of sharp and bittersweet apples. Two safety points matter. Use only sound fruit: moulds on damaged apples produce the toxin patulin, and in experiments some of it survived fermentation into the cider (Wang et al., 2024). And leave out added pectic enzyme and never distil the cider: methanol in apple drinks comes from the breakdown of pectin (Convertini et al., 2022). For a short apple ferment without the alcohol, try our fermented applesauce; for other traditional wild-fermented drinks, see Georgian qvevri wine and Mexican tepache, and our troubleshooting guide for films and off smells.