The Food Lab: How to Make Awesome Pho in 1-Hour
It's time for another round of The Food Lab. Got a suggestion for an upcoming topic? Email Kenji here, and he'll do his best to answer your queries in a future post. Become a fan of The Food Lab on Facebook or follow it on Twitter for play-by-plays on future kitchen tests and recipe experiments.
There are times in life when devoting six hours to a single project seems like a good idea. Watching a Walking Dead marathon to procrastinate on the book you're supposed to be writing. Looking at funny pictures of cats and reading comments from irate atheists when you should be sleeping. Making Vietnamese beef noodle soup the traditional way on a chilly Sunday in the fall.
Then there are those times when you're not in it for the long haul. Times when you'd rather just watch a 4-minute Youtube video, play the world's stupidest and shortest video game, or have dinner on the table in about an hour.
One solution for the dinner problem is to just make large batches of the traditional broth, freezing the extra in flat-laying cryo-back bags to quick and easy defrosting at moment's notice.
Another solution is to just figure out a way to make the darn stuff in record time from start to finish. My goal: full-flavored pho in 1 hour or less. I knew it was an exercise in futility to try and come up with something that tastes as rich and complex as the real deal, but I'd settle for 90% as good in 20% of the time.
Start your stopwatches, because here we go.
Traditional pho is made by simmering beef bones and meat along with a few aromatics for around 6 hours, straining the broth, then serving it with the cooked meat, some sliced raw meat, hydrated rice noodles and other garnishes.
Outside of the meat, the basic flavors of pho are pretty simple: charred onions and ginger (or a bit of sweetness, smoky depth, and pungency), star anise, cinnamon, cloves, and occasionally other spices (for aroma), fish sauce (for salt and its savory umami qualities), sugar (for sweetness, duh), and a slew of stir-in herbs and such at the finish.
There's no need to streamline the stir-ins, as they take no time at all to cook. Likewise the fish sauce and sugar.
Spices, too, have their flavors extracted in under an hour, so we can leave them alone as-is. I like to put mine in a cheese-cloth pouch, making them fast and easy to remove and discard.
Normall, I'd broil my ginger and onions or roast them directly over the open flame of a gas burner. This requires about 25 minutes of time and a couple extra pans or racks to clean. For my fast pho, I skip the oven or burner and cook my onions and ginger directly in the pot I'm going to make the soup in.
The char is not quite as even or deep, but you can get some great caramelized flavors and just enough smoky char in just about ten minutes. This gives us plenty of time to think about the meat.
Before we can devise a new method, we first have to figure out exactly what our goals are. What happens when you simmer meat in water to make a broth?
Locked in this piece of beef chuck are various aromatic molecules and texture-altering proteins.
When you simmer it, there are actually two distinct things going on. First off, we're extracting and altering flavor. As muscle fibers heat up, they contracts, expelling proteins, fats, and aromatic molecules, like toothpaste coming out of a tube. These molecules get dissolved in the liquid, adding flavor.
Simultaneously, we're altering texture. This occurs when certain proteins present in the connective tissue that runs through meat—mainly collagen—break down and are converted into gelatin, a protein with the ability to form a microscopic, loose connective matrix within the broth, making it feel thicker and more unctuous on our palate.
I decided to first focus on faster flavor extraction, then come back to work on texture. First off, starting with a good quality canned broth and doctoring it up is a pain-free way to get a quick flavor boost. Though pho is traditionally made with beef, canned beef broths are universally pretty awful, consisting mostly of flavor enhancers and tasting tinny and thin. Canned chicken broth tastes much more like homemade, and provides a relatively neutral background to build a broth upon.
My next thought was to use more cuts of beef, or to try and find a more flavorful one, but I quickly shot that one down. From my previous explorations in pho, I knew that even with the most flavorful cuts of beef, flavor extraction still takes several hours at least.
But here's the thing: that flavor resides within long muscle fibers that slowly heat and squeeze out their contents into the water. So why not just make those long fibers shorter?
Cutting the meat into small cubes speeds things up considerably, but even better is to do this:
Gross? Maybe. But fast and flavorful? You bet. I found that by grinding the meat before adding it to my simmering liquid, I could decrease the time it takes to extract flavor by a good 3 or 4 hours, getting the job done in record time.
The only downside is that after cooking, the meat becomes un-servably dry and flavorless. But since we're getting all the good stuff out of it anyway, I was perfectly content to discard the spent beef and serve my soup with some freshly sliced cooked and raw flank steak in place of the selection of long-simmered cuts.
Using ground beef poses one other problem: It clouds up the broth as bits of extracted protein and gunk dissolve too finely to be strained out. To solve that problem, I turned to a classic French technique used to make a consommé. By combining the ground meat with a bit of egg white before simmering it, the entire mass forms a single, fragile raft of proteins that float on the surface of the stock.
As the broth slowly simmers, it rises up through that raft in little geysers, falling back down its net-like structure. The raft ends up performing double duty, both adding flavor, and acting as a super-fine filter to entrap all kinds of impurities. By then carefully skimming off the raft and discarding it, you're left with a crystal-clear, brightly flavored broth underneath.
Chopping meat finely helps you extract flavor much faster, but unfortunately it does nothing for hastening the creation of gelatin.
The issue is that the conversion of collagen to gelatin is a time-dependent operation. Higher temperatures can speed the process a little bit, but with a normal pot, your temperature range is restricted to under 212°F, the boiling point of water at standard atmospheric pressure. For this reason, making a broth in a pressure cooker that can get hotter than the normal temperature of boiling water makes for a very fast broth with plenty of body. Unfortunately, pressure cookers are expensive and not everyone owns one. I wanted a way to do it without the pressure cooker.
One way to do this is to simply start with more collagen. Beef connective tissue contains some, but there are other, much more concentrated sources.
Younger animals who don't have fully developed bones or muscles have a far greater proportion of collagen in their bodies. This is the reason why veal and pork roasts have such a crazy sticky and unctuous mouthfeel. The cheapest and easiest source of young animal meat by far is chicken backs. Most commercial chickens are slaughtered at under 2 months of age. Most of their bones are not even fully hardened by this age, making them prime candidates for easy gelatin extraction.
Take a look at this broth, made with just ground beef and chilled overnight:
...versus this broth, made with beef and chicken (you can ignore the difference in color - this was due to testing different charring methods on the aromatics):
The difference is huge. A plain beef broth is watery and runny, while a chicken and beef broth is thick enough to scoop up until distinct solid pieces.
Tasted side by side, the chicken-based broth was universally favored by tasters, and none of them picked up any overtly chicken-y aromas. The beef and aromatics are strong enough that they override and underlying chicken flavor.
The broth was close, but not quite as rich as I'd like it. The solution? Just add pre-extracted gelatin. Commercial gelatin is made by processing animal bones with acidified solutions that makes gelatin extraction fast and economical.
A few packets of gelatin bloomed in the chicken broth before simmering took my broth from pretty tasty to sticky, rich, lip-smackingly delicious. The kind of broth you don't just want to lick off your own lips, but from the lips of everyone dining with you as well.
Please show some restraint when serving.
With the broth done, the rest comes together in a snap. Soaked rice noodles, a bunch of herbs and bean sprouts, come lime wedges and condiments, a few thin slices of raw flank steak that cook gently in the hot broth, as well as a few slices of flank steak that was simmered along with the rest of the broth.
Is it as great as a full-blown pho? Nope. But it's almost as good, and I guarantee it'll be on the table, ready to eat in less time than it takes you to hit 50 meters in QWOP.
Get The Recipe!
About the author: J. Kenji Lopez-Alt is the Chief Creative Officer of Serious Eats where he likes to explore the science of home cooking in his weekly column The Food Lab. You can follow him at @thefoodlab on Twitter, or at The Food Lab on Facebook.