The Filipino sour soup known as Sinigang can contain any variety of meats, poultry and seafood, and is typically studded with a variety of local vegetables. Depending on the region of the Philippines, a range of native fruits can be used to give Sinigang its trademark tang. And although vinegar is a vital ingredient in Filipino cooking, it is never used as a souring agent for Sinigang.
The typical souring agents that can be used include unripe tamarind pods and leaves, kamias (a very sour green fruit pod native to the Philippines), guava, starfruit, tomatoes, as well as lemon, calamansi and dayap (another variety of Philippine lime).
But since Rhubarb is so plentiful this time of year in my neck of the woods (and also because tamarind, kamias, guava, starfruit and dayap don't grow in my neck of the woods), I decided to try and use the sour red stalks to bring the tang for a Pork Sinigang.
Rhubarb? In soup? Yes. And it works wonderfully! Although rhubarb is typically used in desserts, a savory Sinigang application isn't as crazy as it sounds. Besides lending the necessary sourness for a proper Sinigang, rhubarb also provides a nice crunchy texture in much the same way that daikon or taro traditionally would in the Filipino sour soup.
And besides, using Rhubarb in Sinigang will trip out even the most palate-progressive of all your Filipino friends. It's a culinary curveball!
"rhubarb, rhubarb, rhubarb"
In fact, I myself was hesitant with this experiment. But after my first bite, the rhubarb quickly reminded me of a Fish Sinigang soured with Kamias that I had in the Philippines a few years back. So, plop a bowl of this sour, ruby-studded soup in front of the most hardened of Sinigang purists and they'll quickly come to believe in the savory souring power of rhubarb.
Pork and Rhubarb Sinigang
To make this Sinigang, you will need a total of 1-1/2 pounds of fresh rhubarb. 1 pound will be needed for the broth, and the other 1/2 pound will be chopped and added to the soup at the last minute to provide more sourness and texture. When buying rhubarb, choose long, slender, and firm stalks that are deep red in color.
I also used boneless country-style pork ribs in this recipe, but regular pork spareribs would work great, but so would shrimp or even salmon. Sinigang be flexible, folks.
For the broth:
1 pound fresh rhubarb
8 cups water
For the soup:
1.5 pounds cubed pork (I used boneless country-style pork ribs)
Salt and freshly ground black pepper
1 tablespoon canola oil
1 onion, diced
5-6 cloves garlic, minced
2 tablespoons fish sauce, plus more to taste
2 mild yellow chili peppers, pierced through with a knife
1/2 pound cherry or grape tomatoes, halved
1/2 pound fresh rhubarb, cut into 1/4-inch pieces
Fresh greens, such as chopped bok choy, kangkong, or spinach (I used spinach)
Lemon wedges, or kalamansi halves, for serving
To make the rhubarb broth, trim away and discard any leaves from the rhubarb stalks (the leaves are toxic). Roughly chop the rhubarb into about 1-inch chunks. Add the rhubarb chunks, along with the 8 cups of water, to a large pot over high heat. Bring the pot to a boil, then cover, reduce the heat to low, and simmer until the rhubarb is completely soft, 10-15 minutes. Strain the broth through a fine mesh sieve set over a large bowl. Using a wooden spoon, mash the rhubarb in the sieve to extract as much liquid as possible. Discard the rhubarb pulp and set the broth aside.
To make the soup, season the cubed pork with salt and pepper. Heat the oil in a large pot or Dutch oven over moderately high heat. When the oil is hot, add the pork to the pot and brown on all sides, 2-3 minutes per side. Brown the pork in batches if necessary so as not to overcrowd the pot.
Transfer the browned pork to a large platter and set aside. Add the onions to the pot and cook until soft and wilted, 2-3 minutes. Toss in the garlic and cook until just beginning to brown, 1-2 minutes. Return the browned pork to the pot, along with any accumulated juices from the platter. Pour in the rhubarb broth, stirring the bottom of the pot to scrape up any browned bits. Stir in the fish sauce, chili peppers and the tomatoes. Bring the pot to a boil, then cover, reduce the heat to low, and simmer until the pork is tender, 45-60 minutes.
Taste the soup, and adjust the seasoning as necessary with more fish sauce.
During the last 10 minutes of cooking stir in the chopped 1/2 pound of rhubarb and simmer until the rhubarb is tender, but not mushy, 5-10 minutes. If using bok choy, add it at the same time as the rhubarb. If using greens that wilt more quickly, like spinach, just stir it in at the last second after you've removed the soup from the heat.
Serve the Sinigang with lemon wedges or kalamansi halves on the side, to adjust the sourness as needed. Also serve alongside steamed white rice.
Pork Sinigang Soured with Rhubarb