Acorn-fed ham: what it is, how to recognise it and which to choose

‘Acorn-fed’ is one of the most used and least understood words on a ham. It is not a way of saying it is good, nor a brand, nor an area: it is a category defined by law, with specific conditions on what the pig has eaten and how it has lived. An acorn-fed ham comes from an Iberico pig that has done its final fattening in the dehesa, roaming free, eating acorns and pasture. Everything else (the price, the sheen of the fat, that sweet, lingering flavour) comes from that.

What the standard requires for a ham to be called ‘acorn-fed’

The Iberico Quality Standard (Royal Decree 4/2014) classifies each ham by two things: the pig’s feeding and management, and its breed. ‘Acorn-fed’ is the answer to the first: pigs fattened during the montanera on acorns and pasture. The other two possible answers are ‘free-range grain-fed (de cebo de campo)’ (raised outdoors, with pasture and feed) and ‘grain-fed (de cebo)’ (raised on a farm, with feed). A ham is not ‘a little bit acorn-fed’: either the pig did the montanera or it did not.

The montanera: autumn and winter in the dehesa

The montanera is the final fattening phase. When the acorns ripen and fall, the herds go out into the dehesa — holm oaks and cork oaks scattered over pasture — and feed on what they find: acorns and grass. It is regulated: the pigs enter the dehesa between 1 October and 15 December, and must spend more than sixty days there. They walk a great deal and eat slowly, and those two things, exercise and acorns, are what change the meat.

That is why acorn-fed ham is expensive and cannot be otherwise: each pig needs a great deal of land and a whole season, and the acorn harvest is what it is each year. More montanera cannot be manufactured.

Black label and red label: the two acorn-fed hams

Within acorn-fed, breed separates two hams, and each carries its coloured label on the shank. It is fitted by the slaughterhouse, with a unique number for each piece, and must stay there until the piece is sold.

• Black label: 100% Iberico acorn-fed. Pigs of 100% Iberico breed, from breeding stock registered in the herdbook. It is the only one that the standard allows to be called ‘Pata Negra’.
• Red label: Iberico acorn-fed. The same montanera, with a pig crossbred at 75% or 50% Iberico breed.

The acorn diet is complete in both. What changes is the genetics: 100% Iberico marbles the fat somewhat more finely and gives a more intense slice; the red-label ham is, for many people, the best balance between what you pay and what you enjoy. If it is your first acorn-fed ham, start with the red label.

How it shows in the slice

• The fat: fluid and glossy, it softens with the warmth of your hand. It is the first thing you notice and what most distinguishes acorn-fed from grain-fed.
• The marbling: fat infiltrated within the lean, not just around it.
• The flavour: sweet, long, with a finish that lingers. It is not saltier or stronger; it is more persistent.
• The aroma: it opens up at room temperature. An acorn-fed ham straight out of the cold seems like a different ham.

A word of warning from the trade: none of this can be seen from the outside. The shape of the hoof, the slenderness of the shank or the colour of the rind certify nothing. The only thing that certifies that a ham is acorn-fed is its label (or, on a sliced pack, the packaging label in that same colour).

Time: what the label does not tell you

The label says which pig it was; it does not say how long the piece has been cured. And acorn-fed ham needs time: its fat withstands and benefits from long cures that would dry out a leaner ham. Our 100% Iberico acorn-fed ham is cured for more than 48 months, and our Iberico acorn-fed ham (50% Iberico breed) for more than 36. The shoulders, which are smaller pieces, for more than 24. We cure them in our curing house in Castilla y León, and the months are shown on each product page.

Acorn-fed ham or shoulder

The ham is the hind leg and the shoulder is the front one. Same pig, same montanera, same label. The shoulder is smaller and has proportionally more bone: from a ham you get roughly half its weight in slices, and from a shoulder, around forty per cent. In return it cures sooner, has a more direct flavour and lets you try acorn-fed with a more manageable piece. For a household of two or three, it is usually the sensible choice.

Whole, boneless or sliced

• Whole, bone-in: the complete experience and the one that keeps best. It calls for a ham stand, a knife and a bit of skill.
• Boneless: the same ham without the bone, for slicing by machine or by knife without a ham stand. No waste.
• Sliced: vacuum-packed packs, ready to open a little while beforehand and serve. To give to someone who isn't going to start carving, or to have acorn-fed ham at home without starting a piece.

An acorn-fed ham is a montanera, a breed and a few years in the curing house. The label certifies the first two; the third is down to whoever cures it.

Are acorn-fed ham and Pata Negra the same thing?

No. ‘Pata Negra’ can only be said of 100% Iberico acorn-fed ham, the black-label one. A red-label Iberico acorn-fed ham is acorn-fed, but it is not ‘Pata Negra’. And the colour of the hoof certifies nothing: what certifies it is the label.

Does the acorn-fed pig eat only acorns?

During the montanera it eats acorns and the pasture of the dehesa. Before that stage, like any Iberico pig, it has been raised on pasture and natural cereal feed. What defines acorn-fed ham is that final fattening roaming free, which is what transforms the fat.

Why does the fat of acorn-fed ham glisten and melt?

It comes down to what the pig has eaten. Acorns produce a more fluid fat than that of a pig fed only on compound feed, which is why it softens at room temperature and leaves that sheen on the slice. It is also why it should always be served at room temperature: when cold, that fat is hard and has no aroma.

How should you store an acorn-fed ham?

The whole piece: in a cool, dry place, at a stable temperature; once started, with the cut surface covered with its own fat and a cotton cloth. Sliced: in a cool, dry place or in the fridge; if you keep it chilled, take it out a while before serving so that the fat regains its proper texture.