“24-Hour” Dirty Pho
Total Time: ~14hrs divided into 2 days Serves: 6
This is a translated recipe from Leighton Pho’s 24-hour concentrated beef pho adapted to a 8-Qt Pressure Cooker. He includes a 3-Liter Beef Pho Road Map of his process but some details are either oversimplified or overlooked. This rewrite aims to provide clear instruction for the average home cook.
Required Hardware:
Stockpot (5-Qt or larger)
Sieve
Useful Hardware:
Thermometer
Cheesecloth
*Recipe developed using an 8-Qt Instant Pot. Adjust recipe if using a smaller pressure cooker.
Phase I - 1:1 Bone Stock
Total Time: 9hrs Roasting: 30-45min Pressure Cooking: 6hr45min Prep & Clean Up: 1hr30min
Ingredients:
3 Kg (6.6 lbs) Beef Marrow and/or Knuckle Bone*
3 L (3.1 qt) Water
*or any beef bone available to you
Phase one, or day one, is all about bone stock; roasting the bones, removing the impurities, and extracting the flavors with pressure cooking. This recipe uses a 1-to-1 ratio, so every 1Kg of bones requires 1L of water, resulting in 1L of super concentrated bone stock. I’ve found that 3Kg of bones and 3L of water will reach the max fill line in an 8Qt Instant Pot, adjust accordingly if your pressure cooker is smaller.
Brief Instructions:
1. (Option-A) Remove Impurities. Soak the bones in cold water for 24hrs in the fridge. Discard water, rinse, move on to Step 2.
2. Roast the bones at 450-500F (232-260C) for 30-45 minutes, until golden or dark brown.
3. (Option-B) Remove Impurities. Skip step if using Option-A. Parboil the bones. Bring water to a boil, add bones and continue to boil for 10 minutes. Drain, rinse, move on to Step 4.
4. Add bones and clean water to the pressure cooker. Pressure cook on high for 6 hours and allow the pressure to naturally release, takes about 45 minutes.
5. Separate the fat from the stock and chill both of these in the fridge overnight.
Detailed Instructions:
1. (Option-A) Remove Impurities. The slow and lazy method. Put the bones in a container of cold water and let it soak for 24 hours in the fridge. This process draws out the myoglobin and other impurities that could give the stock an off color and taste. Discard the water, rinse the bones, and move onto roasting.
2. Roast the bones. Preheat the oven to 450-500F (232-260C). Spread the bones on a foil-lined baking sheet. Leighton’s pho recipe uses marrow bone. These contribute a lot to the flavor but that doesn’t mean you shouldn’t use other types of beef bone, use what’s available and cheap. The connective tissue on the bone is what contributes the color and collagen which is crucial to this recipe. I’ve done a comparison of bones with and without connective tissue posted at the bottom. Roast the bones 30-45 minutes until they take on a gold or brown color.
3. (Option-B) Remove Impurities. The quicker, busier method. Skip this step if you’ve chosen Option-A. Bring a pot of water up to a boil and parboil the bones for 10-15 minutes, notice the gray scum floating to the surface. The scum usually subsides around 10 minutes. Drain and rinse the bones, move onto Step 4.
4. Add the bones and 3L of water to the pressure cooker. Depending on the shape of the bones you’re using you might not be able to add all 3L of water, that’s okay, it’s a concentrated stock so there’s some wiggle room to add water later without sacrificing flavor. Do not fill past the maximum fill line.
5. Pressure cook the bones. Set the pressure to high and cook for 5-6 hours. Thicker bones like marrow and knuckle will need more time, set it for 6 hours; smaller bones like ribs and neck, set it for 5 hours. I did some testing at different intervals, that info is included at the bottom. For depressurizing, you’re going to let it naturally release, this takes about 45 minutes, the bones continue to cook during this process. Do not use the fast release function, we don’t want the stock to boil and spray through the vent.
6. Separate the fat from the stock. Upon opening the lid, you’ll be greeted by a solid golden layer of tallow. Ladle this into a separate container, we’ll need it for the next phase. For the bones, what you’re looking for is hollow, bare bones where the marrow has melted and the connective tissue has mostly fallen off the bone. If there were any scraps of meat attached to your bones they should be small fibers floating around in the stock. Depending on how much tissue was on the bones the stock should have some shade of brown/dark brown.
7. Strain and chill the stock. Pass your stock through a sieve and give it a taste, it should have a rich bone beef flavor with a slightly oily texture from the collagen. It’s unseasoned, so it won’t have incredible flavor but it should taste more like a stock and not diluted beef water. The final volume of stock won’t be exactly 3L because some of that volume was converted into fat. In my tests I averaged around 2700ml stock to 300ml tallow, this will greatly depend on the bones you’re using. Chill your stock quickly to preserve flavor and to limit possible contamination of bacteria while in the “Danger Zone” of 40-140F, you can use a water chill method to bring down the temperature quickly or portion into smaller containers and put in the fridge overnight.
8. Perform the jiggle test. The next day, take out your stock and (optionally) skim off the top layer of fat. Give the container a slight shake, the stock should hold its shape and jiggle, resembling a Jell-O consistency like in Leighton’s broth video (10:30 mark). If your stock is watery and not holding a shape there could be a few reasons why, I talk about those in a section at the bottom of the document. If you didn’t pass the jiggle test, don’t worry! It has flavor and will still make an excellent pho, there’s no need to salvage the stock or start over, continue with the process.
Phase II - Seasoning
Total Time: 4hrs45min Roasting & Searing: 30-45min Simmering: 3hrs Prep & Clean Up: 1hr
Ingredients:
Base
3 L (3.1 qt) Beef Bone Stock
0.5 Kg (1.1 lbs) Chuck or Brisket*
Beef Tallow
Aromatics
1 Brown Onion
1 5” Knob Ginger
Spices
20 g (0.67%) Star Anise
14 g (0.46%) Black Cardamom Pods
12 g (0.40%) Cinnamon
2 g (0.06%) Cloves
Seasoning
35 g (1.17%) Kosher Salt or Rock Salt
55 g (1.83%) Yellow Rock Sugar or White Sugar
20 g (0.67%) LSP, or Knorr Hat Nem, or Mushroom Seasoning
X-Factor (Optional)
250ml Oxtail stock or animal stock of choice
Phase two, or day two, is building the layers of seasonings, spices, and aromatics that shape the flavor profile to about 95% of our intended target. Ideally, you would begin the seasoning phase on the day you intend to serve pho, while the spices and aromatics are at their absolute best. Leighton’s method uses a commercial oven and stove-top but I will include a method that only uses an Instant Pot.
*I used chuck roast for accessibility and affordability, use brisket or whatever protein you have access to at a reasonable price.
Brief Instructions:
1. Slice the ginger and onion in half. Roast the chuck, ginger, and onion at 450-500F (232-260C) for 20-30min until the chuck turns golden brown and the aromatics take on char. Boost the charring by placing the aromatics under the broiler or over an open flame until edges blacken.
2. Pour a thick layer of beef tallow into a stockpot over medium-high heat and sear off the chuck, about 1 min each side.
3. Remove the chuck and add the aromatics, allow to fry 2-3 minutes.
4. Add the spices and stir constantly until fragrant, about 1 minute.
5. Deglaze the pot with all 3L of bone stock and scrape the fond from the bottom with a wooden spoon.
6. Place the chuck back in the broth and bring it just shy of a boil. As the broth heats up, add in the seasonings one at a time, tasting in between each. Aim for over-seasoned.
7. As the broth begins to boil, lower the heat to a simmer (200F or 93C) and maintain that temperature for 3 hours with the lid partially on.
8. Remove the chuck, chill and slice for serving. Discard the fat, aromatics, and spices, and pass the broth through a sieve to remove particulates.
9. (Optional) Add the oxtail or animal stock to return to 3L of volume, stir to dissolve.
10. Portion and chill servings until ready to use.
Instant Pot Instructions:
1. Turn on the Sauté function and set it to high. Add a thick layer of beef tallow and sear the chuck on all sides until golden brown, about 10-15 minutes. Slice the onion and ginger in half, lengthwise.
2. Remove the chuck and add the aromatics, fry until the edges turn a dark golden brown, 5-10min.
3. Add the spices and stir constantly until fragrant, about 1 minute.
4. Deglaze the pot with all 3L of bone stock and scrape the fond from the bottom with a wooden spoon.
5. Add the chuck back in. As the broth heats up, add in the seasonings one at a time, tasting in between each. Aim for over-seasoned.
6. Put on the lid and switch to the Pressure Cook function. Set the pressure to high for 20 minutes and allow the instant pot to naturally release.
7. Remove the chuck, chill and slice for serving. Discard the fat, aromatics, and spices, and pass the broth through a sieve to remove particulates.
8. (Optional) Add the oxtail or animal stock to return to 3L of volume, stir to dissolve.
9. Portion and chill servings until ready to use.
Detailed Instructions:
1. Roast the chuck and char the aromatics. Slice the onion and ginger lengthwise and roast them along with the chuck (or your beef of choice) at 450-500F (232-260C) for 20-30 minutes until golden brown. Boost the charring on the aromatics by placing them under a broiler or over an open flame until the edges blacken. I wrapped the chuck in butcher twine as an experiment to see if this helped lock in moisture and present a cleaner deli slice at serving. The results were inconclusive on the moisture but it did present much cleaner slices that were easier to cut thinly for serving, this is optional and not necessary.
2. Sear the chuck. Heat the stockpot over medium-high heat and add a thick layer of beef tallow, aim for 1cm layer. Sear the chuck about 1 minute each side, taking it from a golden brown to a darker brown.
3. Fry the aromatics and spices. Remove the chuck and add the aromatics, fry for about 2-3 minutes. Add the spices and stir constantly until fragrant, about 1 minute, these can burn quickly so don’t fry for too long. As for the spice blend, there is some flexibility. Fennel seed, coriander, and cassia bark are common pho ingredients and you’re welcome to add or subtract to your liking. I opted to add fennel seeds since I had them in my pantry. A note on black cardamom, give the pods a hard whack with the flat side of a heavy knife or a pan to crack open the pod to help release the aroma.
4. Add the bone stock. Deglaze the pot with all 3L of your bone stock and scrape the fond from the bottom of the pot with a wooden spoon. If you’re short of 3L of bone stock, top off with water to return to 3L of volume.
5. Bring to a high simmer and add the seasoning. Increase the temperature to high until bubbles begin to appear and then lower the temperature to maintain a simmer. We want to maintain a high temperature but we do not want boiling, make small adjustments to the heat until you find the sweet spot, around 200F (93C). If you’re following the Instant Pot method, put the lid on and pressure cook for 20 minutes. While the broth heats up, add your seasonings one by one. Percentages are included if you’re not following the 3L recipe. Start with adding the salt: 35g or 1.17% of 3000ml (make sense?). Stir until dissolved and give it a taste, it should be too salty. We want to overseason our broth because we need it to season the noodles and toppings we add later. It shouldn’t be so strong that it’s disgusting, it should taste like you accidentally added a bit too much salt. Follow the process with the sugar, dissolve and taste, and finally the umami seasoning. I’ve listed a few options for the umami seasoning: Leighton calls for Hat Nem in his original recipe but it’s not easily accessible in the U.S. so he made his own blend, LSP, that includes Hat Nem in addition to his own special ingredients. For affordability and accessibility, I opted for Mushroom Seasoning. It lacks the beef extract of Hat Nem but shares other ingredients that add a rich savoriness with just the slightest hint of mushroom that you barely notice. Adjust any of the ingredients to your liking. Partially cover the pot with a lid and simmer the broth for 3 hours, flipping the chuck halfway through to ensure even cooking.
6. Remove the chuck and strain the broth. At 3 hours, the chuck* should be jiggly and easily pierced with a chopstick. Allow to cool and wrap in plastic wrap and place into the fridge until ready to serve, do not slice while it’s hot. Discard the aromatics, spices, and fat layer from the broth. Pass the broth through a sieve, (optional) add a cheesecloth to remove smaller particles.
7. (Optional) Add the X-Factor. Leighton adds an optional step of adding oxtail stock as another dimensional layer of flavor. It’s a subtle addition and a nice finishing touch. It is not a make or break for the broth, your pho will not taste bad if you skip this step. He mentions chicken and pork as an alternative. I opted to use a homemade chicken stock that only contains stewing hens to top off the volume lost during simmering back to 3L. His recipe specifies to add this during the serving phase but I opted to add it now since I intend to freeze portions for later.
8. Portion and chill. Chill the soup quickly to preserve flavor and minimize contamination.
*Cook time will vary for different cuts of beef. Brisket and chuck work well at 3hrs, different cuts need more or less time, do your research for optimal cooking times.
Phase III - Serving
Total Time: 35min Simmering: 5min Prep & Clean Up: 30min
Ingredients:
Base
500 ml Beef Pho Broth
70 g dried flat rice noodles or 112 g fresh pho noodles
Seasoning
5-10 ml (1-2 tsp) Fish Sauce (recommend Red Boat or Three Crab)
MSG (optional)
Toppings (examples)
Chuck or brisket, thinly sliced
Steak, thinly sliced
Beef Meatballs
Beef Tendon
Tripe
Red/Yellow Onion, thinly sliced
Scallions, sliced (green parts)
Cilantro, Chopped or Whole
Garnishes (served on the side)
The third and final phase is serving which includes seasoning adjustments that round out the flavor profile of the bowl, elevating it from 95% to 100%. Portion sizes, toppings, and garnishes are completely up to you, I’ll be referencing Andrea Ngyuen’s, The Pho Cookbook.
Brief Instructions:
1. Prepare your noodles. Soak dried noodles in hot water for 30min then boil for 10-60sec or boil fresh noodles for 10sec, rinse either option under cold water.
2. Prepare your toppings & garnish plate.
3. Heat broth and add seasoning adjustments to taste.
4. Bring broth to a rolling boil and (optional) preheat your bowl.
5. Combine noodles, toppings, and once the broth boils, pour slowly over the top. Serve.
Detailed Instructions:
1. Prepare your noodles. For dried noodles (right): soak in hot water for 30 minutes, until soft and opaque, aim for slightly past al dente. Top off with hot water as needed to maintain temperature. Time varies depending on the noodle, start checking around 15 minutes, drain, rinse, and reserve. Before serving, boil the noodles for 10-60 seconds and rinse under cold water. For fresh noodles (left): boil for 10 seconds, strain, and rinse under cold water.
2. Prepare your toppings and garnish. Take any toppings and garnish that’s in the fridge and set it out on the counter until it reaches room temperature, about 30 minutes.
3. Heat broth and adjust seasonings. Heat the broth to a warm temperature that you can taste without burning your mouth. Add the fish sauce in small increments until you can barely taste the fish, put as much or as little as you like. Also use this time to adjust your salt, sugar, and hat nem to your preference. Leighton suggests the addition of MSG but the soup is already so rich in umami that it seems unnecessary. Add a pinch or skip entirely.
4. Boil the broth and heat your bowl. Crank the heat and allow the broth to reach a rolling boil but dont leave it boiling for too long, you don’t want to evaporate all that hard work. While you wait, heat your bowl in the microwave for 1 minute or pour hot water into the bowl and allow it to heat up. The goal is to keep the pho hot for as long as possible - a cold bowl and toppings will drop the temperature at serving, you need the high temperature to cook any raw protein.
5. Assemble the bowl. Add your noodles and toppings into your heated bowl. Slowly pour the boiling broth over the toppings, making sure to pour onto any raw protein.
6. Serve and enjoy while hot.
Bonus Information
I. Selecting the Bones
There’s a variety of beef bones that can be used in making an excellent stock so here’s a quick guide on what to know for this recipe. If you don’t want to read further, then just look for beef marrow, or knuckle, bones with plenty of gristly connective tissue for a cheap price.
The signature characteristic that separates Leighton’s pho from traditional forms is the high concentration of flavor and collagen he extracts from the bones. Marrow and knuckle bones contribute a substantial amount of flavor, collagen, and fat for the price making it the ideal choice for this recipe. These bones are often sold together as “beef bones” and are the most common to find.
Another characteristic is the rich, brown color that comes from roasting the connective tissue. The tissue is made up of ligaments, tendons, and muscle that cling to the bone. In my tests, I used processed bones that were without connective tissue and unprocessed bones with connective tissue. The processed bones did not take on much color during roasting and resulted in a lighter, pale color after pressure cooking compared to the unprocessed bones that developed a brown color that only got darker the longer I cooked the bones. Aside from color, connective tissue adds more collagen and flavor making it essential to this recipe.
If you’re unable to source marrow or knuckle there are other options that work as a fine replacement. Pelvis, scapula, and ribs contain high collagen and flavor. Spine and neck have more connective tissue and offer more flavor, or “meatiness” to the stock but less collagen. Oxtail is high in collagen, flavor, and fat and is a popular choice for braises and stews at a price. You can mix and match however you like and still create an amazing bone stock.
You don’t need expensive bones to make an amazing stock. Leighton mentions using grass-fed beef bones during his testing and found no difference compared to regular bones. I found similar results using organic local beef bones from a specialty butcher versus regular supermarket bones. Sure, there’s likely a difference in nutrition, but we’re talking flavor, not nutrition - go with what’s affordable to you.
Bonus Information
II. Pressure Cooking Testing
The only reason this recipe exists was to see if I could replicate Leighton’s 24-hour bone stock process in a fraction of the time using a pressure cooker. I made 4 batches of bone stock cooked from 3 to 6 hours (on high pressure).
Batch #1 was cooked for 3 hours. A pressure cooking tip that was passed on to me was that for every 1 hour of pressure cooking equals about 8 hours of stove-top cooking. This tip has generally served me well and has not let me down until now. At 3 hours, the marrow and tissue was mostly intact, the soup was an opaque white, and tasted like a watered down beef stock. There was plenty of fat extracted from the soup but no collagen.
Batch #2 was cooked at hourly intervals of 3-1-1, checking between each phase, so 5 hours plus the 45 minutes of natural release between each phase. This time consuming process was to find that sweet spot of good color, flavor, and tissue breakdown. At 4 hours, I was beginning to see the results I was after and by 5 hours I had achieved what I wanted. What I couldn’t factor in was the passive cooking that was happening during the natural release, so I conducted two more tests.
Batch #3 was cooked for 5 hours. Some of the tissue had broken down and what remained was barely hanging onto the bones. The stock had an opaque light brown color and good gelatin development that passed the jiggle test. The flavor tasted like a well-rounded beef bone stock.
Batch #4 was cooked for 6 hours. Even more tissue breakdown with marrow dissolving into the soup. The stock had a darker color and stronger gelatin development than batch #3. The taste was similar to batch #3 but the boost in gelatin really rounds out the flavor profile making it better than #3 in my opinion.
The verdict, both 5 and 6 hours is an acceptable amount of time for a well-rounded beef bone stock, but the 6th hour noticeably elevates the final stock making it my preferred option.
Bonus Information
III. Refining the Tallow
Bone stock produces a lot of tallow that can be saved for other uses than pho. Here’s a quick way you can refine the tallow skimmed from your stock. You’ll need a saucepan or pot, preferably one with high walls to help keep the splatter and mess under control.
1. In a cold saucepan or pot, add your tallow. Try to separate the tallow from the water, it’s easiest to do while the tallow is cold. Turn the heat on to low.
2. As the tallow heats up, the water will cook off causing the oil to sizzle and spatter, this is okay. If the oil is aggressively splattering, turn the heat down until it’s controllable. Cook for 10-15 minutes until the sizzle and splatter subsides, there’s a noticeable change in sound, it becomes much quieter. Keep an eye on the oil, if there’s any pieces of debris floating around be sure to stop before it burns.
3. Pass the oil through a sieve and into a mason jar. The tallow will keep for 12 months on the counter or longer in the refrigerator if stored properly.
A final note; don’t bother keeping the tallow used in phase two after it’s been simmered in spices, it takes on a bitter flavor and aroma, use your tallow sparingly in this phase if you intend to keep some after.