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Phở khô nấu chân không (dry-style Pho cooked sous vide)

Beef cooked sous vide (under vacuum) for 24 hours with phở spices was so dramatically tender and flavorful and deserving of extra attention, serving phở dry-style was our way to highlight our favorite new star. Serving noodle soups dry with broth on the side showcases the flavors of the meats and emphasizes their textural interactions with the other ingredients, all before a rush of hot broth reconstitutes the noodle soup experience. Phở isn’t usually served this way, but we were inspired by the dry variant of Hủ tiếu Nam Vang (Phnom-Penh style noodle soup). Surprisingly, this style also made phở more drink-friendly (more on that later) !

Hot bowl of clear phở broth  served on the side of soft noodle and sous-vide cooked beef

When we first set up our DIY sous vide and low temperature cooking equipment, one of the first applications we pursued for it was for phở: to optimize texture and maximize flavor in each slice of beef. Cooking under a vacuum drastically slowed down the reactions that caused loss of flavor and moisture. Consequently, the cooking time could be extended and cooking temperature decreased to dial in the exact desired texture of the final product.

Cooking beef shank sous vide for 24 hours gave us a beautifully pink cut that combined the best qualities of thịt tái and thịt chín. Thịt tái literally means rare meat; in the context of phở it refers to very thin slices of eyeround served rare and only scalded with hot broth before serving. Thịt tái is tender, but carries only the subdued flavor of lean beef. Thịt chín literally means well-done meat; in the context of phở it refers to thick slices of one of the tougher cuts of beef cooked in phở broth. Thịt chín has all the fragrance of phở and well cooked marbled beef, but can be dry and chewy.

Sliced sous vide beefshank cooked with phở spices; note the color and the ruby red tendons.

Sous vide beef shank was tender and moist, and tasting both of unadulterated rare beef and well seasoned phở with its aromatic array of spices. The slices were cut thicker than thịt tái, more like thịt chín or roast beef. The effect was that there was more there to be savored – a defined structure and an initial toothsome resistance that becomes quickly yielding.

Making Phở khô nấu chân không / dry-style Pho cooked sous vide :

Phở spices for sous vide beef shank (for 1/2 lb)

We started the day before, mixing spices and roasting ginger and onions on top of the range. For each 1/2lb of beef shank we added a half of our usual bag of gia vị phở (spices), a piece of ginger about 2 inches in length, and a quarter of a large white onion. As shown in the picture above, we smashed up the pieces of ginger, star anise, and black cardamom to facilitate flavor transfer.

Beef shank was rubbed with salt, pepper and sugar, then was placed with all the spices in a mason jar or in a cooking-safe bag (not vacuum sealable) inside our usual vacuum sealable marinating bag (not specified as safe for cooking). Air was evacuated out of the mason jar and the bags. The method for vacuum sealing a bag inside a bigger bag was first described in the Makezine forum. We found negligible differences between the two; if anything, the beef cooked in mason jar emerged more visually appealing, with striking ruby red tendons. We’ll stick with mason jars going forward.

Beef shank and phở spices vacuum sealed and ready to go into the water bath

Cooking temperature was 131 degrees Farenheit / 55 degrees Celsius. Cooking time was 24 hours.

The next day, we made phở the usual way: blanched oxtails and beef shank (blanching: added meat to a pot of boiling water and brought back to a boil, then drained and placed meat under cold running water for 1-2 minutes) to get rid of unpleasant odor. We then refilled the pot with water, then added oxtails and beef shank. When the pot was boiling again, we lowered the heat to maintain a soft rolling boil and skimmed the accumulated aggregates to get a clear broth. Phở spices, roasted ginger and onion were added and the broth simmered for another 2 hours with occasional skimming. Seasoned with salt, sugar and fish sauce to taste.

Meanwhile, we washed tripe extensively with vinegar and salt to remove excess odor. Beef tendons and tripe were then cooked in boiling water & slices of ginger in a separate pot. Tripe was removed after 30 minutes to preserve its crunchiness. Tendons were cooked for 2 hours until chewy but not mushy.

Condiments and garnishes for phở included sliced onions flash pickled in vinegar and black pepper, chopped cilantro and scallions. The herbs plate included húng quế (basil), ngò gai (culantro), rau om (rice paddy herb), and beansprouts.

An assembled bowl of phở, waitng for broth one way or the other.

As we had predicted, serving phở dry-style really highlighted the sous vide cooked beef shank. What we did not anticipate was that this phở variant was also very drink-friendly. Dry style phở facilitated the Vietnamese past time of dipping most everything in sauces, in a hoisin and chilli sauce mixture in this case. By mechanisms not yet fully understood, being able to savor the meat by itself and/or with just a smidgen of sauce just called for alcoholic accompaniment. To further test our hypothesis and eliminate the possibility that we were simply lushes, we had phở served the traditional way (hot bowl of brothy phở noodle soup): nope, no hankering for a cold sake at all.

So there you have it: a new way of serving phở that highlights the best qualities of beef and is also conducive to nhậu (a Vietnamese word for indulging in alcohol and food, with roughly equal emphasis on both.)

This is our contribution to June edition of Delicious Vietnam, a web round-up of Vietnamese food-related posts hosted this month by … us! The event was founded by A food lover’s journey and Ravenous Couple.


  1. How interesting! It is a known fact that SV is a technique which yields superior tasting meat. I just love how you guys combined the flavours of Pho into the beef. Well done guys! I so would love to try this but not everyone has a vacuum sealer at home… 🙁

    • Hello, fellow cancer biologist cum aspiring restauranteur,

      Thanks for visiting and commenting! As interest in SV cooking has been growing, there have been a number of ways around a vacuum sealer. Depending on the application, you can even make do without drawing a vacuum altogether, as shown here:

      For us, the bigger technical problem was getting a precise enough water bath. Makezine has plans for a simple one for less than $100. Maybe you can also haunt your university’s property disposition center for a retired lab grade one?

  2. Interesting! I think you are right, this is a great way to cook beef with all that spices that define pho!

  3. Hmm… this is interesting. But how does the noodle get flavorful if the broth is served on the side? Since the meat is marinated, what happens if the noodle and everything is served with the broth, and the beef is on the side?
    I’ve been travelling like mad and I can’t write at all lately, so I don’t have any submission for this month’s Delicious Vietnam 🙁 But I’m looking forward to reading your roundup!

    • Thanks, Mai, for visiting and commenting.

      Just like with dry-style hủ tiếu nam vang, the noodle was briefly dunked into the broth (in the pot) to get softened before being put in the bowl. For phở served with broth (regular style), the noodle doesn’t have enough time to absorb the flavors anyways (we do have a way to make noodle flavorful in and of itself for bún bò Huế…but that deserves a full post in the future, so stay tuned :D). The flavors are in the meat, the broth and the sauces you put in, which you can still do with this dry-style phở.

      Hmmm…maybe we should have described how we ate our new version of phở better in the post (our focus was mostly on how we cooked beef :D), so people don’t think it isn’t flavorful. When we ate, we still put in all the regular condiments: hoisin sauce, chili sauce, lemon juice, bean sprouts, herbs, etc. And some broth could be poured into the bowl or could be scooped up in a soup spoon that is full of noodle, meat and herbs, etc; it really depends on the diner. There is a lot more flexibility in this version of phở, because you are free to combine different components in whichever way you like, just like in dry-style hủ tiếu nam vang.

      Interesting idea about serving everything but the meat together. We could give it a try next time. My guess is it won’t be able to accentuate the interaction of textures as much, because the broth could get in the way (less flexibility to combine different ingredients). It might be less drink inducing :)…but we won’t know until we try it.

      We definitely missed you in this DVN roundup. Look forward to reading more of you writing soon.

  4. I don’t like people who mess with traditional food. You don’t mess with masterpieces.

    • Well, you know, the masterpieces are always going to be there, we can’t corrupt or ruin them. You love them and you want to enshrine them in a museum, we love them so we create these dishes to participate and be a part of the tradition that produced the masterpieces. It’s riskier than just following the recipe – some people won’t like what we do, but hopefully some will and they return to their classic bowls of phở with fresh perspectives and appreciation.
      And people who don’t like the very idea of what we do can stick with their traditional bowls of phở, be it the spartan Hà Nội version, the chicken version, the Southern Vietnamese version with all the fixin’s and extra beef lard, or the leaner North American version with Thai basil and Sriracha sauce.

  5. Great recipe which I like to try but how do you sous vide the meat and spices evenly when cooked in a mason jar as to a vacuum sealed bag?

    • Hi Sammy, thanks for visiting. When we cook under vacuum in a jar, or in a bag for that matter, the meat loses a small amount of juice which helps to distribute the spices evenly. The fact that we cook for so long also gives things plenty of time to spread around makes the uneven distribution of solid spices less of a problem.