After many years of intense work in busy restaurants where meals were made à la minute, I was drawn, like a frantic city dweller to a country retreat, to much slower journeys in food. The transformation of raw pork into the world’s most exalted of hams is slow in every way, and making it each year suits me fine. Not counting time on the hoof, the trimming, salting, aging, and all the maneuvers leading to the finale, an average leg of pork destined for prosciutto takes 14-16 months. It pales in comparison to the decades-long wait for certain vintages of wine, the years required for a wheel of Parmigiano Reggiano to mature, or the interminable aging process of aceto balsamico—its evolution continuing until there is no one left to inherit its legacy. Nonetheless, prosciutto shares a common irreducible ingredient: Time.
As of today, my six prosciutti have been hanging in my home cellar for 232 days and will evolve with as many before they are consumed next spring. As a maker, it’s always a moment of surprise and celebration. Like a kid on Christmas, I can hardly wait to open the gift—in this case, the award of patience—to be savored with family and friends I know will enjoy its consummation.
My cellar, 10 feet underground in the Berkeley Hills, is bounded by one-foot-thick cement walls and an enormous volcanic rock that extends 8 feet beyond a side wall into the earth beyond.
The Berkeley Hills themselves were home to volcanic activity some 10 million years ago, with several centers of volcanism that contributed to the landscape. Our neighborhoods boast stunning architectural features—stairs, walls, and street corner landmarks hewn from the rocks and boulders. One famous monument (“Indian Rock”) attracts sunset gazers to its western summit and rock climbers to its steepest faces. When the backhoe operator encountered a large boulder while excavating our cellar 28 years ago, our remodel budget was strained already, and we were not prepared for this unforeseen condition. But then I had a bright idea. Instead, we would build a wall around it. This rock and surrounding walls, at their depth from the surface, conduct cool and constant temperatures of around 60°F year around, which is ideal for cellaring wine and meat to be cured and aged.
I salt and dry-age prosciutto in an enclosed redwood cabinet with double-paned glass doors. My cabinet is outfitted with refrigeration components to accommodate storing fresh meat and for the salting step for prosciutto. Salt and low temperature protect the prosciutti at this stage when they are most vulnerable to spoilage due to their elevated water content. But once they have taken the salt, I turn off the refrigeration and only use low-velocity fans to stir the air. I manage the conditions for drying mostly by feel and with the use of a thermo-hygrometer, a device that measures air temperature and relative humidity. In large-scale production, rooms for salting and aging prosciutto have sensors that send signals to the HVAC system. The systems modulate automatically with the conditions of the products, delivering heat and cold, air movement, and humidity. It’s all in service of drying the prosciutti evenly from the core to the surface at a slow pace. Nevertheless, a machine cannot make a prosciutto. It’s up to the maker to tell the machines what to do based on a sensory read of the product itself and to adjust the “climate” when necessary by way of the machine controls. My cabinet has no such automatic controls so some maneuvers are manual. Depending on how much meat is in my cabinet, adjusting the humidity may be necessary. With six legs of pork, my cabinet runs at 72 -85% relative humidity at 50-60 F. in the early stages of drying, which is ideal for this number of prosciutti. If I were to load more legs in or other products to be dry-cured, such as salame, I would need a dehumidifier. Conversely, later in the process, I may need to add humidity via a humidifier to maintain the right balance and to keep the products supple.
I am fortunate insomuch as my cellar naturally maintains the right temperature and humidity levels (except at the salting step) and has proven to be an excellent environment for drying 6 prosciutti at a time without the need for refrigeration and humidity controls. Here’s how this setup can benefit the drying process: Since my cellar naturally holds the ideal temperature (around 50-59°F) and humidity (70-80%), it creates a stable environment for the prosciutto to dry slowly, mimicking traditional curing methods. The result leads to my taste for a more authentic aroma, born of the cellar itself. On cold days, I open the doors to the outside to refresh the air. Otherwise, I use the evaporator fans to stir the air within my cabinet. Stagnant air can cause uneven drying and contribute to the growth of undesirable molds. While my cellar naturally provides the right conditions, it’s still essential to monitor the environment periodically. Seasonal changes, shifts in humidity, or variations in the amount of prosciutto being cured can impact the balance.
Using a naturally regulated cellar is also energy-efficient since it reduces or eliminates the need for mechanical refrigeration. This can save on energy costs and make the curing process more sustainable.
In the initial period of salting and drying, the bald surfaces were host to fine white penicillium mold, which subsisted on the moisture released from the interior of the hams. The mold protected the surface from light and oxidation and consumed some of the moisture at the surface. It remained for the first six months or so as the prosciutti respired.
It’s the mold that signals favorable or unfavorable conditions. Too much mold, caused by high humidity in the space inhibits drying. But if it is too dry, the mold will disappear, and the surface will harden, which can be the end of prosciutto if it is allowed to progress. Under such circumstances, water from the interior cannot escape, and the meat is likely to rot. If it is too wet, it will cover the surface in a furry coat, and unwanted mold species may find their way.
Today, I noticed the mold is retreating, leaving a dusty, dry, and slightly hardened surface. I also give them a sniff and a poke, probing the center with the traditional horse shin bone, a sharp,-pointed tapering stick that readily conveys the aroma of the inside of the ham used to gauge the progress of drying and aging. By giving the hams a squeeze of the large “round” muscle, I can tell from the firmness that it’s time to trim and “seal” the hams.
But beforehand, they must be brushed and washed to eliminate the mold and soften the surfaces.
After brushing, I wash all sides of the prosciutto under warm running water, then let them rest for a few days to dry. Then, I trim the surface to reveal the deep burgundy flesh below.
Washed and hung Trimmed “to the red”
Why “seal” a prosciutto, and what does it mean? In Italian, the word for this process is stuccatura, which translates into ‘stuccoing,’ a figurative term applied to sealing a surface with a final protective coat as stucco would be applied as a final coat to the surface of a building. The ‘stuccoing ‘/sealing of prosciutto is an important step in its production and is carried out for several reasons: Applying a layer of paste made from fat and salt protects the surface of the ham from external contamination, such as bacteria, insects, or other possible contaminants. Sealing helps maintain an adequate level of moisture inside the ham, reducing excessive loss of water and contributing to even aging. The layer of fat can also influence the chemical reactions in the meat, contributing to the formation of distinctive aromas and flavors. Sealing can also improve the aesthetic appearance of the prosciutto, giving it a more pleasing uniform look. Finally, during the long aging process, the prosciutto may experience cracks or breaks. Sealing helps stabilize the meat and prevent this type of flaw.
Malleable and waxy pork kidney fat is ideal for sealing the prosciutto. After grinding through a fine plate and salting it, the fat is smeared all over the trimmed surfaces.
Kidney Fat 1/8 inch grind
After sealing, I also press coarse ground pepper into the fat, which leaves its trace flavor when the prosciutto is opened. The whole protective layer is removed before it is sectioned and sliced.
In the next installment on Prosciutto, I’ll share my understanding of the chemical and biological changes that occur as prosciutti ages, leading to its final aroma and satin texture. In the meantime, I wait and dream of good things to come.
Thanks so much for this detail, Paul. It's really important to understand the process. I've been around a lot of prosciutti and jamones over the years but this is the best description I've ever seen. I'm grateful but still not ready to do my own!
I would love to see a tour of this cellar with its incredible boulder!