Two Hour Tonkotsu Ramen! (part 1) / eggs, noodles, pork belly

Sup suuupp so this article is written for all the ramen aficionados reading.  Anyone who’s been to enough good ramen places knows that tonkotsu broth is where all the flavor’s at.  My favorite ramen places, Ippudo NYC and Sapporo in Boston, have one thing in common: a ballin tonkotsu ramen.  The components are few: broth, noodles, pork belly, soft boiled egg, and misc other toppings (green onions, seaweed, maybe some pickled vegetables or buttery corn). When done right, you achieve a soup that is comforting and umami to the extreme.

Now, there are a few resources out there that describe fairly well how to go about making tonkotsu ramen at home (namely http://www.seriouseats.com/2012/02/how-to-make-tonkotsu-ramen-broth-at-home-recipe.html , which I borrowed from in this article).  However, most of what I’ve seen stick to the traditional & laborious 10-hour process.  With a bit of scientific understanding, I’ve crafted a few shortcuts that cut down the whole process to about 2 hours, take a look!

A sneak preview! Tonkotsu ramen broth with braised pork belly, marinated soft boiled egg, seaweed, crispy shallots and green onion

Soft boiled egg

The egg is possibly simplest component of the ramen that actually needs cooking.  Yet somehow, there’s all sorts of confusion about how to actually cook a soft-boiled egg.  I’ve heard techniques that involve putting eggs into water either before or after bringing water to a boil or simmer, then either killing the heat or maintaining a simmer or boil, lid on or off for 5-7 minutes.  

The problem with the techniques I’ve seen is that they are too vague or suffer from too much variability from kitchen to kitchen.  Since water simmers in a range of about 15 degrees, there’s not any good way of knowing what someone means by a “light simmer” unless you’re using a thermometer.  Removing pots from heat can result in totally different water temperatures depending on volume used and pot material.

My preferred technique: boil water (about 1 qt water: 2eggs, erring on the side of excess water), add ‘Large’ eggs straight from refrigerator, allow to boil for 6 minutes uncovered, remove eggs using tongs/ladle/etc and run under cold water for 60 seconds.  This technique is more reproducible between kitchens since most refrigerators are set to 35-38^oF, so the eggs will always have roughly the same starting temperature.  ‘Large’ eggs are roughly the same size and mass due to careful legal regulation. Water always boils at one temperature at a given elevation (212^o F for most of you).   Finally, using flowing water cools eggs more efficiently than eggs in an ice bath (convective and conductive transfer > conductive transfer only), keeping cooking times more consistent and precise.

Left: Large eggs boiled for 6 minutes, 5 minutes 45 seconds, and 5 minutes 30 seconds from left to right.  The 6 minute egg was significantly easier to de-shell. Right: The same eggs, halved.  The six minute egg had a more firm white, while still liquid yolk. 

Side note: I usually put a lot of trust in Serious Eats food lab articles. However, Serious Eats food lab writer J. Kenji Lopez-Alt recommends simmer eggs at 180 degrees for 6 minutes exactly.  Strangely though, in a picture in the same article, you can see that eggs BOILED for 5 minutes are underdone, and 7 minutes have set yolks.  Clearly, 6 minutes at 180 degrees is not enough.  Indeed, I tested this at home and ended up with raw egg all over my shirt after cracking the shell.  A nice model developed by Dr. Charles Williams (http://newton.ex.ac.uk/teaching/CDHW/egg/#accuracy) estimates that an average ‘Large’ egg from the refrigerator will be done at 5 minutes in boiling water (~57 gram egg with initial temperature of 4^o C will reach a yolk temperature of 65^o C, the temperature at which yolk will JUST begin to coagulate).  

A handy flash animation, courtesy of the University of Oslo, http://www.mn.uio.no/kjemi/tjenester/kunnskap/egg/..

A flash animation to help with the calculations on a variation of this formula can be found here: http://www.mn.uio.no/kjemi/tjenester/kunnskap/egg/.  However, one must keep in mind that the whites will be technically done at this point, but that only means they are opaque and slightly gelatinous, rather than firmly set.  In addition, the model makes the assumption that starting at t=0, the boundary condition of the egg is the same as the temperature of the boiling water (essentially neglecting any thermal properties of the shell).  To illustrate this inaccuracy, using the formula to calculate T_yolk at t=0 gives you a temperature of 27^o C, while the overall initial egg temperature is supposed to be 4^o C.   For the sake of getting slightly more firm whites (easier to peel, and just more appetizing to me), and to account for the need for the egg shell to heat up, I’d tack on at least an extra 30 seconds to the 5 minute estimate.  I would give a more precise correction, but couldn’t find any data on the thermal properties of egg shells.

Braised pork belly

Pork belly is notoriously difficult to cook well, in part due to its non-homogeneous composition of fat and meat and high connective tissue content.   As with any cut of meat with lots of connective tissue, the key is always “low and slow” cooking.  This would be another place where a pressure cooker would come in handy, but I’m assuming that most people out there only have one pressure cooker if any, and we’re going to need that for the broth.  Personally, I’ve found that my pork belly has had satisfactory texture with under 2 hours of simmering on the stove (1 hour, 45 minutes of simmering at 190^o F in the braising liquid resulted in pork belly that was gelatinous at the edges with moist/tender meat in the center).  The recipe on Serious Eats recommends 3-4 hours, likely because the pork belly slabs pictured were roughly double the width of mine.  The energy required to heat a piece of meat to “done-ness” is proportional to volume, but heat transfer is proportional to surface area.  Therefore, a cylinder of pork belly that has twice the width of mine, doubling the volume, only has 1.5x the surface area.  By taking a ratio of the surface area-to-volume ratios, I estimate that the larger cylinder would take 4/3 as much time, or that my cylinders would be done in ~2.25 hours. Close enough.

What’s most important is to constantly monitor the internal temperature of the meat-side of the pork belly slab.  Thinner slabs, like mine, will cook faster, and once it hits ~155^o F, it’s time to remove it from the pot.  The only disadvantages of thinner slabs is that they are a bit trickier to slice, and the ends may be slightly drier than the interior (however, these end pieces also tend to soak up more of the marinade, so no big deal).  I recommend letting your cooked pork belly rounds sit in the freezer for 15 minutes or more, and for very consistent slicing, use a mandolin.

Left: Approximately 1" pork belly slabs tied into cylinders.  Center: Uncooked pork belly rounds in marinade.  Right: Pork belly rounds after 1 hour of braising.

Ramen noodles

Ramen noodles are traditionally hand-pulled from dough that has a gluten structure that permits stretching without breaking.  I’ve given this a try for several days, and decided it’s ultimately not worth it.  Half the battle is finding the right dough formulation (lye, water, and protein content) that results in the right amount of gluten formation, and the other half is a long process of kneading, stretching and pulling.  While I’ve thought of shortcuts for the kneading and pulling process, I have no real way of knowing if I’m actually working with a proper dough formulation to begin with.  There doesn’t seem to be much in the way of improved flavor or texture through making them at home, certainly not enough to justify the days of practice it would take to master this technique.

Be sure to check out part 2 for the 2-hour tonkotsu broth!

For the condensed recipe (in part borrowed from J. Kenji Lopez-Alt, with modifications), check out my recipe pages for tonkotsu ramen broth, marinated soft boiled egg, and braised pork belly.

Pretty much every component can be made in advance and reheated as necessary.  The broth will solidify in the refrigerator (since it has high gelatin content), but can be microwaved or reheated on the stove.