How an acorn-fed Iberian ham is made, step by step

Between the day a piece goes into the salt and the day it leaves the cellar, two to four years pass. Here is what happens to the ham in that time, in order and without jargon — and what Spanish law actually governs, which is a good deal less than people assume.

Where this information comes from

The rules quoted here come from public texts: the Spanish quality standard for Iberian ham and the four designation-of-origin specifications, all listed at the foot of the page along with the published work the biology passages come from. We select our pieces on site, in Salamanca, and we know the person who cures them: the last section says what we know of that work, and stops where what we do not know begins. The yield of a piece, its weight loss, the ideal cellar temperature: these figures circulate everywhere and source badly, and we say below where they come from. And we sell Iberian ham: you should know that before reading what follows.

Four stages, and two words that are not among them

Spanish law divides the process into four stages, and it names them. Article 11 of the quality standard lists: salazón, lavado, post-salado, curado-maduración — salting, washing, post-salting, curing.

What is striking is what is missing. Secadero and bodega, the drying loft and the cellar, the two words everyone uses to tell the story of ham, do not appear in the legal list. They are folded into the fourth stage. They are trade words, entirely real and entirely useful, but they are not categories of the standard.

Washing, by contrast, is a stage in its own right, and almost nobody mentions it. It makes sense: after the salt, whatever is still stuck to the surface has to come off, or the piece salts in the wrong place.

The durations in this table are trade orders of magnitude. Only the total time is set by law, and we come to that.

Salt, and how long it takes to cross

Salting is not seasoning, it is dehydration. That is what makes preservation without refrigeration possible, and it is why the stage is short: a few days are enough to set in motion something that will then take months to distribute itself.

Many workshops reuse the salt from previous batches. This is not misplaced thrift: salt that has already worked does not behave quite like fresh salt, and the difference shows in the piece.

Then comes post-salting: nothing visible happens for weeks, and yet this is the decisive moment. A badly post-salted piece will be salty on the outside and flat in the middle, and no amount of cellar time will fix that.

The drying loft, then the cellar

After the cold room, the pieces warm up. Drying begins, and something visible happens: the covering fat softens and migrates slowly inward, between the muscle fibres. In Spanish the trade calls it sudado, the sweating. That infiltrated fat is what gives the melting texture, and it is why a lean pig makes a poor ham — it is all decided long before the salt.

It is also here that the law falls silent. None of the four specifications sets a temperature or a humidity for the drying loft. Two impose a minimum duration, the other two say nothing at all. The most-told stage of the trade is the one the law does not regulate.

Traditionally the regulation is done by hand, opening and closing windows to follow the outside air. Many workshops have since added mechanical control of temperature and humidity, giving mixed lofts: natural ventilation stays, drift is corrected. It is less picturesque and markedly more consistent from one year to the next.

When the piece moves down to the cellar it no longer dries much: it transforms. The enzymes already present in the pig’s muscle work slowly, in the cold, for months. They cut proteins into ever smaller pieces, and it is those pieces that carry the long, mouth-watering background taste nobody quite knows how to name.

In parallel, other enzymes go to work on the fats. The counter-intuitive finding is that it is not the covering fat that makes the aroma but the fine fats of cell membranes. Very fragile in air, they break down into the compounds we smell. In Iberian ham, twenty-eight of them have been identified.

It is also during this stage that small white specks sometimes appear on the slice. They are neither salt nor mould: they are small crystals, a sign of a cure that has gone all the way. We give it a whole article.

One common-sense note to close the stage: a cellar is not air-conditioned to the degree. In a real acorn-fed process, the recorded ambient temperature swings between 15 and 25 °C with the season. The ham lives at the rhythm of the year, and that is deliberate.

What the standard actually requires

Reduced to essentials, Spanish law governs three things and leaves everything else open. It is worth knowing when you read a label.

Compliance with the durations is checked against the workshop’s records. The only physical marker on the piece is the week it entered the salt, stamped on the seal.

Two figures we will not give you. How much weight a piece loses during production: the “30 to 35%” you read everywhere comes from no standard, and the only published measurement on Iberian ham gives 32 to 34%. And what proportion of a piece is edible: no public body publishes it, and the percentages in circulation all come from online shops.

At the workshop that cures our pieces

Our pieces are cured in the province of Salamanca, with no designation of origin. It is a choice we stand by, and it has a concrete consequence: only the national standard applies. It sets the durations and the traceability, and leaves the settings to whoever does the curing.

Salting there follows the day-per-kilo rule of thumb, with the departures practice demands: weight, fat, season. We work with someone whose job is precisely to know when to depart from it, and we will not pretend to know better than he does.

The drying loft is a mixed one: natural ventilation, with control of temperature and humidity. We would rather say so than tell you about windows opened by hand, which would make a prettier sentence. The piece then finishes in the cellar, where it spends its last years before being graded.

In total, our acorn-fed hams come out between 44 and 48 months, and our shoulders between 32 and 36. The legal minimum is 730 and 365 days: we are well beyond it, and that is what makes a whole piece expensive.