What Is an Acorn?

We can say that we enjoy Jamón Ibérico de Bellota thanks to one extraordinary fruit: the acorn. But do you know what an acorn is? Or what its properties and benefits are? In this article, we'll tell you everything you need to know.

When we talk about an acorn, we're referring to the fruit of trees belonging to the Quercus genus, which includes the holm oak. According to the Royal Spanish Academy Dictionary, an acorn is "the fruit of the holm oak, the oak tree, and other trees of the same genus, such as the cork oak." Acorns have a hard, light-brown shell that contains a single seed inside and usually measure around 2–3 cm long.

Before discussing the nutritional properties of acorns, it's worth noting that today they are no longer a common part of our daily diet. However, in the past they were an important ingredient in the Mediterranean diet. Nowadays, acorns are mainly used to produce certain types of flour and liqueurs and, most importantly, to feed Iberian pigs.

The acorn, origin of everything

Acorn Properties

Cerdo ibérico comiendo bellotas en la dehesa

Iberian pigs feeding on acorns in the dehesa

High content of oleic acid

One of the most remarkable characteristics of acorns is their high content of oleic acid, the same healthy fat found in extra virgin olive oil. Oleic acid is known for helping reduce LDL ("bad") cholesterol while supporting healthy HDL cholesterol levels. Thanks to this, Jamón Ibérico de Bellota is recognized for its role in a heart-healthy diet.

The Benefits of Acorns in the Iberian Pig's Diet

An acorn-based diet, combined with the pigs' daily exercise in the dehesa and their unique genetic ability to naturally infiltrate fat into the muscle, produces exceptionally juicy meat. But Iberian pigs do not eat only acorns. After weaning, they are fed specially formulated feed, and depending on the production system, two programs are followed:

Pigs selected for the montanera

Receive a less nutrient-rich feed. Once they reach around 100 kg, they are released into the dehesa to feed naturally on acorns until they reach 180 kg. They produce Jamón Ibérico de Bellota.

Pigs that remain on the farm

Receive a more nutritious, vitamin-enriched feed, producing 50% Iberian Cebo Jamón.

What Is the Montanera?

The montanera takes place from mid-October through approximately the end of March, when acorns reach their peak ripeness. An Iberian pig can only be labeled "Jamón Ibérico de Bellota" if it has fed freely on acorns during this period and in the Spanish dehesas. Upon arriving in the dehesa at around 100 kg, they walk long distances. This exercise is key to allowing the healthy fat from the acorns to infiltrate the muscle, creating the marbling that gives every slice its unmistakable flavor and juiciness.