Sidra natural

What it is

Sidra natural is the traditional cider of Asturias, in northern Spain. Cider apples are crushed and pressed, the juice ferments with no sugar added, and the cider matures through the winter before it is bottled in spring. It is dry, sharp and only faintly sweet, with a light fizz that comes from fermentation. The classic form is lightly clarified at most, and it is served by pouring it from a height, a technique called escanciado.

The fruit is Malus domestica, the cultivated apple. Asturian cider makers use regional varieties chosen for their sugars, organic acids and phenolic compounds, and most ciders blend several. Sweet apples give fermentable sugar. Acidic varieties give malic acid and sharpness. Bitter and bitter-acid varieties give tannin and structure. The mix decides much of the cider's character.

The protected designation Sidra de Asturias / Sidra d'Asturies covers cider from authorised apples grown and processed in Asturias, which means all 78 municipalities of the Principality. For protected sidra natural, sugar may not be added, the carbon dioxide must come from fermentation, and the cider must reach at least 5% alcohol by volume. These are product rules. They are not a full recipe, and not every Asturian cider tastes alike.

Natural cider normally goes through two fermentations. Yeasts turn apple sugar into ethanol and carbon dioxide. Lactic acid bacteria can then turn sharp malic acid into softer lactic acid. In the traditional method both groups of microbes come from the fruit, the press and the cider house, although many producers now manage their cultures and temperatures more closely.

The words around the drink are Asturian. Orchards are pomaradas, cider houses are llagares and cider bars are chigres. UNESCO inscribed the whole system in 2024: orchard care, harvest, pressing, fermentation, pouring, festivals and shared drinking. That recognition covers a living practice, not one fixed formula.

History

Apples and cider have a long record in Asturias. Spain's 2013 heritage inventory says medieval documents mention cider from the eighth century. That gives the drink an early anchor, but the charter and its wording were not examined, and the statement cannot tell us how the cider was made. Strabo is sometimes cited for ancient drinking customs in the region, yet ancient references to fermented drinks do not show that the present method existed.

By the twelfth and thirteenth centuries, written records show apples as an important crop, with contracts and references to pressing installations. Presses (llagares) stood among other rural processing equipment, and cider fitted into the agricultural year alongside livestock and household land use. Records do not show that orchards held the same varieties, or the same fermenting microbes, from one century to the next.

From the late sixteenth century, accounts describe plenty of cider and some substantial producers. Production grew in the seventeenth century and orchards spread further in the eighteenth, helped by agricultural societies that encouraged planting and nurseries. Technical writing on cider became more common. The drink moved from farm households towards a wider regional market.

In the nineteenth century cider expanded with towns and industry. Larger commercial cider houses changed the presses, the distribution and the packaging. Chigres became familiar places to meet, and pouring cider from a bottle took on its modern identity. The 2013 inventory records older uses of cider at pilgrimages, rural gatherings, weddings, christenings and funerals.

Recognition came in steps. The designation Sidra de Asturias was registered in the European system in December 2005. Asturias entered its cider culture in its intangible heritage register on 2 July 2014, and UNESCO inscribed it on the Representative List in December 2024. The product specification was amended in 2025, and a further amendment was published on 26 October 2026. None of these dates shows that fermentation and serving have stayed unchanged since the Middle Ages.

How it works

Apple juice for cider holds glucose, fructose, sucrose, malic acid, nitrogen compounds and phenolic substances. Yeasts break the sugars down by glycolysis to pyruvate, which they convert to acetaldehyde and then to ethanol, releasing carbon dioxide and regenerating the NAD+ that lets glycolysis continue. Nearly all the alcohol comes from sugar already in the apples, since none is added.

A spontaneous fermentation passes through several yeast populations. A 1990 study of Asturian cider found Saccharomyces cerevisiae and an apiculate yeast then called Kloeckera apiculata in traditional and experimental fermentations. Later work identified Hanseniaspora uvarum, Hanseniaspora valbyensis, Metschnikowia pulcherrima and other non-Saccharomyces yeasts. In one cellar followed over the 2000 and 2001 harvests, strains classified as Saccharomyces bayanus dominated early and S. cerevisiae became more common towards the end. The bayanus name in older molecular studies covers organisms whose species limits are hard to draw today.

The second main change is malolactic fermentation, in which bacteria convert L-malic acid into L-lactic acid and carbon dioxide. This softens the acidity and can change the cider's stability and aroma. Asturian research published in 1996 tested controlled malolactic conversion with Leuconostoc oenos, now called Oenococcus oeni, and found that adding the bacterium after most of the sugar was used worked well in the experiment. That is a research finding. It does not mean traditional producers add it.

Aroma comes from more than one pathway. Yeasts make higher alcohols, acetate esters and ethyl esters, and later bacterial activity adds ethyl lactate, organic acids and other volatiles. Microbes can also transform phenolic compounds from the apple. In Spanish natural cider, maturation raised ethyl lactate, ethyl acetate, 4-ethylphenol and 4-ethylcatechol, and Lactobacillus collinoides has been studied for forming some volatile phenols. Not all of these compounds are welcome at every level.

Apple chemistry matters as much as microbe names. Polyphenols give bitterness, astringency and oxidation reactions, and malic acid gives the fresh-apple sharpness until malolactic conversion. Glycerol and sorbitol add to the non-volatile body, and standard cider yeasts do not ferment sorbitol well. Oxygen drives oxidation and acetic acid bacteria. Because fruit, cellar and microbes differ from one cider house to the next, no single species list or fermentation schedule fits every sidra natural.

How it's made and why each ingredient and step matters

It starts with cider apples picked for ripeness, acidity, sugar and phenolic content. The Regulatory Council groups the authorised apples by their technological behaviour and does not set one blend. Raxao and Durona de Tresali add acidity, and Regona adds acidity and bitterness. Sweet and semi-acid varieties balance the juice. Blending lets the maker adjust the must before fermentation without sugar, which the protected category forbids.

Harvest usually begins in October, though varieties ripen at different times and some are picked later. At the llagar the apples are inspected, washed and sorted, and fruit that is unripe or overripe, contaminated or decayed is rejected. The apples are milled to pulp and pressed. Wooden beam presses are traditional, and stainless-steel hydraulic or pneumatic presses are common now. Pressing leaves most of the solids behind and gives fresh must, called sidra dulce before it ferments.

The juice goes into fermentation vessels: wooden barrels or toneles, or stainless-steel tanks today. The yeasts and bacteria of the juice and cider house do the work, though producers manage them in different ways. Yeast turns sugar into ethanol and carbon dioxide, and the maker follows sugar, acidity and above all malic acid. The Regulatory Council describes fermentation at a controlled temperature but gives no number and no fixed duration.

Malolactic conversion usually follows or overlaps the later alcoholic stages. It depends on the bacteria present, the alcohol, the acidity and the cellar. When the cider has developed enough it is racked off its heavy sediment, which also evens it out. Racking is traditionally done in January and February, with tasting and bottling from spring. These are seasonal habits, not fixed dates.

Traditional sidra natural is bottled with no added sugar and no added carbon dioxide. It keeps a mild natural fizz that shows during escanciado. Filtered cider (sidra natural de nueva expresión) is processed differently, and sidra natural espumosa gets its own secondary fermentation. The traditional method gives no apple weight, juice yield, yeast dose, temperature programme or batch time; those would have to come from a named producer or a controlled recipe.

Regional and historical variations

Cider is made across Asturias, but the Comarca de la Sidra is the area most tied to orchards and cider houses. It includes Villaviciosa, Colunga, Nava, Bimenes, Cabranes and Sariego. Gijón and Oviedo are other major centres of production and drinking. Cider houses differ from place to place, yet the designation covers the whole Principality and not just the best-known towns. The blend of apples differs between producers and from year to year.

Apple diversity is basic to the tradition. The Regulatory Council keeps descriptions of regional varieties and their acidity and phenolic character, working with SERIDA, the regional agricultural research service. Examples are Raxao, Regona, Blanquina, De la Riega, Durona de Tresali and Verdialona. The current designation recognises many more varieties than the short list in the original 2003 regulations, and the authorised list has to be checked against the current specification.

Traditional sidra natural differs from sidra natural filtrada, also called sidra de nueva expresión. The filtered cider is clarified more thoroughly and is poured straight into the glass without the high pour. Sidra natural espumosa is a third category, made by a secondary fermentation in bottles or pressure tanks. Some producers use selected yeast cultures within the traditional method, and others rely on the microbes of their own cellar.

Asturian cider is not Basque sagardo, though both are generally dry, acidic apple drinks fermented spontaneously. Comparisons have found differences in volatile compounds, including esters and phenolic transformation products. The histories, apple choices, pressing practices and serving customs also differ. Escanciado belongs above all to bottled Asturian natural cider, while Basque cider has its own barrel-serving and tasting customs.

Other apple drinks are separate things. Sidra dulce traditionally means freshly pressed, unfermented juice, and some ciders are only partly fermented. The specification amended in October 2026 adds ice cider (sidra de hielo) as its own product, and it is not made like sidra natural. Rural cider used to be pressed on household presses and kept in wooden barrels, while registered producers may use controlled stainless-steel equipment. The link between apples, fermentation and shared drinking has stayed recognisable through all that change.

How it's eaten and used

The best-known Asturian custom is escanciado, the high pour. The escanciador or escanciadora holds the bottle above the head and the glass low, below the waist, and lets a thin stream fall onto the side of the tilted glass. The impact frees dissolved carbon dioxide and makes a brief burst of fine bubbles. The Regulatory Council adds that some volatile acidity is released too. The effect fades fast, so the cider is drunk straight away.

A small serving is a culete or culín. The Regulatory Council recommends at least 100 mL for a proper escanciado. The glass is wide and thin-walled so the falling cider can be watched, and a bottle is shared round a table in successive small pours rather than filling each glass. The usual serving temperature is about 12 to 14 °C. Filtered natural cider is served without escanciado at about 8 to 10 °C.

Sidra natural belongs to sidrerías and chigres, where it is poured, shared and drunk with food. It is also drunk at home, outdoors and at traditional llagares. An espicha first meant opening a barrel to taste it, often with neighbours who had helped on the farm, and later came to mean a meal or gathering built around cider. Typical food includes tortilla, cured meats, cheese and empanadas.

Cider marks the seasons too. At the autumn amagüestu, roasted chestnuts are eaten with fresh sweet apple juice or with cider. The 2013 heritage inventory records the frarada in Tineo, a pre-wedding custom in which cider was shared, along with cider at pilgrimages, weddings, christenings and funerals. These customs have changed over time and are not identical in every municipality.

Cider is also cooked with. Chorizo a la sidra cooks sausages in it, and restaurants use natural cider in sauces and in fish and meat dishes, where its acidity and fermented-apple flavour set it apart from fresh juice. The pressed pulp, magaya, has historically been used for animal feed or agricultural purposes. UNESCO's 2024 recognition covers the whole network of orchards, pressing houses, serving practices, festivals and shared knowledge, not just the bottled drink.

Reading results and problems

Cider makers judge sidra natural partly by how it behaves in the pour. Three Asturian terms describe it. Espalme is the quick, complete disappearance of the surface foam. Aguante is how long fine bubbles last in the liquid, which should fade gradually. Pegue is the small, even traces of foam left clinging to the inside of the glass. These are traditional sensory marks of quality. They do not test for pathogens or chemical contaminants.

Acidity needs careful reading. A sharp, refreshing taste is normal, but too much acetic acidity points to a fault. Acetic acid bacteria oxidise ethanol when oxygen is present, and some yeasts make too much volatile acidity. Malolactic conversion changes malic acid to lactic acid and the perceived sharpness with it. Measuring malic acid, lactic acid, volatile acidity and sugar tells you more about progress than taste does.

Studies of Asturian natural cider show wide differences between cellars and between years. They found several Saccharomyces strains and a succession of non-Saccharomyces yeasts during alcoholic fermentation. That variety adds to the character, but it also makes spontaneous fermentation less predictable. A cider that ferments vigorously is not necessarily free of contamination, so clean equipment, sound fruit, monitoring and temperature control still matter.

One defect has its own name. Filado is a cider that turns viscous or oily and does not break when poured, which can come from microbes making extracellular polysaccharides. Too much surface foam, poor persistence of fine bubbles or coarse foam residues also count as faults at a traditional tasting. Other practical problems are heavy oxidation, a vinegar-like smell, mould and fermentation that carries on after bottling. Not every sensory fault is a health risk, and a cider without visible faults is not shown to be safe.

Fruit quality is the main food-safety question. Mouldy apples can carry patulin, a mycotoxin from Penicillium and other fungi. The FDA warns that pasteurisation does not reliably destroy patulin and advises rejecting rotten or mouldy fruit. Fermentation can lower patulin in some fruit drinks, but the product is not simply removed, and that is no reason to press mouldy apples. Fresh juice can also carry harmful microbes before it ferments, so selection, washing, clean pressing and validated controls matter.

Spanish national rules add analytical limits. The consolidated Real Decreto 72/2017 sets volatile acidity below 2.2 g/L as acetic acid and methanol below 200 mg/L for the cider categories it covers, and the standard was amended again in 2026. These are product quality limits. They are not a food-safety protocol, and they do not replace the current protected-origin specification. The 5% alcohol minimum for protected sidra natural is a product rule too. Nothing in these definitions gives a safe spontaneous-fermentation schedule, a pH endpoint, a bottle-pressure limit or a shelf life.