Preparing for a larger gathering, I started looking for quantities of pork bones beyond the 1 lb. pack of neck bones that can be found at some local groceries. After several misses, I landed at The Butcher and Larder, where they happily sold me 12 lbs. of bones and trotters. I took further advantage of their stock and picked up a couple of jowls. A bit pricey, but good value for the quality (and scarcity) of the meat. When selecting bones, I've found that the trotters offer a goodly amount of collagen, and shank bones contain yummy bits of marrow. Having these things makes a world of difference.
I've found several variations online, and after a little tweaking have settled on the following recipe. I don't believe that my method has been exactly described, so this will contain all of the steps:
Tonkotsu BrothYield: 2 gallons
Ingredients:10 lbs pork shank, back and neck bones
3 trotters
3 Tbsp. lard
1 large onion, fine dice
8 cloves garlic, coarse chop
1 knob ginger, 2" long, coarse chop
1 tsp baking soda
Equipment:12 qt or larger stock pot
Small (1.5 qt) sauce pan
Skimming device
1 clean sink basin
Optional:Electric kettle
Additional large pot or dutch oven
If desired, use these devices to keep larger quantities of near-boiling water ready to shorten cooking time.If at all possible, have your butcher cut all of the bones into small (2-3" long) pieces.
We Want Clean Bones:Add bones to stock pot, then cover with water. Bring pot to rolling boil, then back off to maintain a medium boil. Scum and blood WILL accumulate; skim aggressively until accumulation slows down, about 10 minutes. Dump pot and contents into sink. Rinse the bones under running water to remove any stubborn bits of blood. Rinse and scrub the stock pot.
The (long) Main Event:Refill the pot with the squeaky-clean bones, cover with water, and bring to boil. Just like last time, back off a little to maintain a medium boil. For the next 7 hours, keep the boil going, adding water as needed to keep the bones covered. This is where the milky, opaque color is developed; a stark contrast to the classic French stock technique. Drop a dime in the bottom of the pot here, and you won't know that it's missing.
Since I trimmed the jowls, there was a goodly amount of pork fat that was looking for a purpose, so I rendered it and came up with about 8oz. of lard.
Sometime around hour 5, heat lard in the small saucepan over medium heat. When the oil begins to shimmer, add in the onions, garlic and ginger. Sprinkle the baking soda on top (yes, I did this after reading Kenji Alt's article on onion dip) and cook to caramelize the aromatics. After the onions have cooked down a bit (12-15 minutes), the mixture should be a light to medium brown. Dump the entire contents, lard and all, into the stock pot.
At hour 7, meat should be falling off bones, and most, if not all, of the collagen and marrow should have dissolved. You now have a huge pot of stock. Using whatever straining device(s) you have, strain it all through.
Congratulations! Now all you have to do is figure out how to get rid of the remnants and cool the stock.
Next step, seasoning the broth.