How to Roast a Pig with a Rock

Remains of a Stone Age Pig Roast

This pig was cooked largely by the heat of a rock. It is a 16 lb roaster pig that cooked for almost nine hours. A long slow cook over a low heat that produced a tender delicious meal for 34 people and a pack of wolves. The last five hours were heated just by the rock. You might ask, “why would Walter step back to the stone age to cook a pig? Is this some paleo diet thing?” Not at all!

I wanted to cook a pig for a clan gathering. The problem was we were a long distance from the event and had no facilities at the site to do the cooking. Rather than bring a BBQ I figured out how to just bring the heat – I put it inside a rock. Thermal mass to the rescue, once again!

Stone Age Pig Roast Roasting Box
For sizes see the handy Roaster Size Chart

The issue is we can cook the pig at home just right but I worried that on the long car trip the pig would cool into the danger zone which is between 40°F and 140°F. In this middling temperature range food spoilage bacteria can grow. Around 80°F to 100°F they grow rapidly. Keeping the pig hot without over cooking it was my goal. That meant a long slow cook for this suckling pig which is the ideal way to do a pig roast.

The process began with brining the pig for two days. We actually thawed it in the brine which is a little trick that keeps the brine cold and automatically monitors the temperature. The frozen pig went into the bath of salt water, spices and ice cubes. By monitoring the ice cubes you know the temperature of the brine bath. As they melt, add more ice. No tech. I also happen to have a digital thermometer for my data logging but that is just a toy, an extra, and by no means necessary. Ice water tells the true tale and is how one calibrates thermometers.

Someone emailed asking about feeding 34 people with 16 lbs of roast pig. Realize this was a potluck and not the only food there. In this case I had a 16 lb pig on hand and no idea how many people would show up. Sometimes it is 150 people and sometimes its 15 people. Since it is a potluck that means there are many other dishes but one never knows what those dishes will be. It works out, as potluck always do. As a general rule I figure 1/2 to 2 lbs of pig per person for pig roasts – it depends on what else is being served at the dinner and who is dining. Teenagers will eat a lot. Older people less, as a rule. If there are lots of other things figure on 1/2 lb. If the pig is the main course with little else then figure on the higher end of the range.

On the morning of the big clan feast our elder son Will woke up early and put the pig in our home oven at 300°F to start the cooking process. He cooked it for about three and a half hours. We raised the temperature to 400°F for the last hour to begin the browning process and crisp the skin.

But that was only about half the cooking time and does not include the key ingredient, the rock. In the oven on the rack below the pig Will had placed a heavy chunk of white granite which had been slowly heating up from the git-go.

Why white granite?” you ask.. Well, I’ll reveal our secret here but you must promise to tell anyone. It doesn’t really matter. Most any dense rock would work. It could have been black granite or marble for that matter. Preferably something without water in it so it won’t explode in the oven and not a light weight rock like pumice as those simply won’t store enough heat energy. Soap stone would have worked very nicely but a 2″ thick slab of white granite is what we had on hand. Use your available resources. So now you know the secret ingredient to the perfectly cooked pig during transportation, and even the right color of stone!

While the pig cooked the rock was heating up for that entire four hour period. Meat doesn’t get all that hot because of the water in the meat. But the rock came up fully to temperature by the end cook time. I placed the rock on a wire cake cooling rack inside the insulated transport box which was lined with foil. This lifted the rock off the bottom. The rock thus heated the pig from the the bottom up to make sure the meat would continue slowly cooking on our long trip to grandma’s house. Actually, it was great, great, great, great, great, great, great grandma’s house but you get the idea. Over the river and through the woods we go!

The pig in its drip pan went into the box on top of the rock and I covered it with foil to protect it. This also served to reflect heat back downward aiding in the cooking. Close the lid and instant portable 350°F and descending oven. Cheap too. Rock cheap.

I took temperature readings during the pig’s trip to monitor the experiment:

Time Temp Notes
09:10 180 °F Exiting Oven
11:28 192 °F Traveling
13:47 173 °F Arrival and serving
18:13 83 °F Leaving event

The pig looked spectacular, smelled scrumptious and tasted delicious! Everyone was delighted with it. The skin had browned perfectly and was like bacon. Kudos all around for a pastured pig well raised, well cooked, well transported and well enjoyed!

This technique is much like pit roasting but mobile. Pit roasts were something I grew up doing with my father. Each year he would roast big hunks of meat for the clan gathering, wrapping the turkey, beef, pork, chicken and such in layers of wet newspaper. He had dug a pit in the sand bank behind our house and fired it with a large load of wood and some rocks in the bottom. To get it very hot and build up a layer of charcoal he ran a vacuum backwards as a blower pumping air into the bottom of the pit. It was so hot it melted the sand making beautiful glass slag. After the wood was reduced to a hot bed of coals and the rocks were all hot he lowered in the wrapped meat, covered it with a sheet of metal and then sand. Many hours later we dug it up to reveal a delicious meal for the entire gathering.

The next day our dogs dined on the remains, the bits of bone and skin that had not been devoured by delighted relatives. Since the temperature had fallen into the danger zone by the time we left I didn’t save the left overs for our own meal. Had we put it on ice it would have made for good sandwiches the next day but the pack must eat too – they share in the kill. I figure about 30 pigs a year, full size pigs, go to feed our hungry wolves. They pay their way keeping their wild brethren at bay. Much of what the pack eats are the scraps as has been traditional since the stone age.

If you’re interested in roasting a pig yourself and need a pig to attend the event see our Roaster Pig Page for a fine selection of freezer and fresh pigs.

Outdoors: 80°F/63°F Sunny
Tiny Cottage: 69°F/62°F

Daily Spark: Life is a work in progress. Keep improving every day, every week, every month, every year. Persist.

About Walter Jeffries

Tinker, Tailor...
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11 Responses to How to Roast a Pig with a Rock

  1. Peter says:

    re: spark — every Monty? Do we mean like Monty Hall, or Monty Python? :-)

  2. CarolG. says:

    I believe you meant to refer to pumice instead of pomace. I love the idea of using a rock to finish cooking while you transported the roast.

  3. Sally H says:

    Just FYI this works for potatoes too. Except you don’t need a rock.

    Wash your baking potatoes. Let them dry, then grease up the outside and prick with a fork. Stack them directly on the racks of your oven. Bake at 350 until they are about half-way done. Use tongs to put them into paper grocery bags, filling the bags about half-way full, then turn down the tops. Put the bags into a cooler or other well insulated box. (If they need transport, you can do it now.) Leave for at least an hour. When you take them out of the cooler they will be cooked through.

    I had an event for which I need 300 baked potatoes. This is the method I used. Worked perfectly.

    • Great to know!

      On a related note, sometimes we stuff turkey, duck, chicken or pigs and sometimes we don’t. Stuffing results in slower cook times. In retrospect I decided I should have stuffed this pig as we had so much cook time I would have gotten the benefit of cooking some potatoes, carrots, onions, etc inside the pig in it’s juices. Next time!

  4. David Lloyd Sutton says:

    Mouthwatering post!! Another methodology you might find useful on Sugar Mountain: The Straw Box. I’m fond of cast iron cookery, and a pioneer technology was to have your evening meal, typically in a dutch oven or bean kettle, boiling hot in the morning campfire, then to insert it in a wooden box stuffed with straw or hay, the stuffing confined by upper-edge-tacked-down fabric (like wagon canvas). This was formed to a specific cooking vessel before securing and trimming the fabric. A lid, similarly insulated, would cover the contents, the box and lid would be latched or strapped, and food would cook safely, without coals or flames, during the days’ journey. This was the western migration’s crock pot! A long-term capital good well worth an afternoon’s assembly time. I’ve used a variant of this with cardboard, for single stationary cookings, using cast iron, of course. Power free, not needing attending during a work day . . . and very effective.

  5. Juan says:

    You should try a precision circulator for sous vide cooking. You could even sell pre cooked meat without much hassle.

    • Coincidentally, today I was experimenting with sous vide and cooked our lunch that way. The inspector and I had a long conversation about the possibilities.

      • Juan says:

        With a few big styrofoam coolers, a thermometer, a solar water heater, and a wood fired water heater you could cook a lot of meat (and eggs!) with unheard of efficiencies. I think it’s the best way to value add in a meat producing farm. You’re also making sure your customers don’t overcook (or undercook) their pork. It even extends shelf life significantly. And in your case part of the year you can harvest ice to do the post cook chilling, which can be a significant energy expenditure otherwise. I’ve been thinking about this for a while hahaha

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