Dragon’s Eggs — Double-smoked Scotch Eggs

Smoked what?!?!

You are aware of smoked meat. Perhaps you have heard of smoked eggs. You may have even made either yourself. But had it occurred to you that you can smoke eggs and meat together?

Here we will cover:

• How to time an egg for the perfect consistency (and the science behind it!)
• How to smoke eggs without making them rubbery
• How to smoke a Scotch egg
• How pink smoke rings are formed

This results in a smoky experience par excellence.

This requires quite some effort, so this definitely is meant to be the showcase component of a good meal. Best enjoyed with friends.

Ingredients

• 8 large eggs
• 1.5 lb ground beef (or pork, or a 50/50 mix!)
• 1 tspn ground cumin
• 1 tspn paprika
• ½ tspn ground nutmeg
• ½ tspn ground ginger (secret ingredient, shhh)
• 1 tbspn canola or good quality vegetable oil
• 1 medium onion, diced
• ½ tspn ancho/chipotle/other mild chili — optional
• Coarse sea salt
• Cracked black pepper

Tools

• Smoker (or Weber grill set up with a two-zone fire)
• Charcoal
• Wood chips for smoking (oak/hickory/apple)
• Disposable aluminum pan
• Ice cubes

In a large pot, boil enough water to cover eight large eggs.

Gently lower the eggs while stirring slowly, to avoid cracking. Do not boil vigorously.

An egg contains two semi-permeable membranes just inside the shell, allowing small molecules (e.g. gas molecules in the air) to pass through, but not larger ones, such as protein molecules [1]. As a consequence, a sac of air forms between the brittle shell and the internal fluid. Allowing the egg to rotate a few times reduces the stresses on the outside shell while it acquires an even temperature differential.

When we finally eat these delicious morsels we want the yolks to ultimately have a soft and sticky texture, with the whites set tenderly but not rubbery. But this is the first stop of a four-stage cooking tour-de-force! We will need to manage our temperatures throughout this process (see below). In this stage, we want the yolks to be soft and the whites to be largely set. How do we achieve this precision?

It’s so easy!

You merely need to raise the temperature of the yolk boundary to around 150-155°F (65-68°C) for a small amount of time. Solving the heat equation for a spherical egg [2], you get the equation in the image above, where K, ρ and c are the effective thermal conductivity, density and specific heat capacity of an egg respectively. For a large egg (M~60g) directly from the fridge (T_initial=4°C) this comes to a fairly even 6 minutes. You could go as long as 6 minutes 30 seconds. Note this will depend on your altitude, which affects the boiling point of water (T_water).

Or… you could also just use a mobile app (my trusty “Egg Timer Free” for Android by Mobication has always given perfect results) and set to “largely set/soft solid”.

Immediately remove the eggs and place them in a large bowl of iced water. Peel once cooled. This cooling is an important step to halting the cooking process, otherwise the internal mercury will keep on rising and your pursuit of egg-sellence will be in vain.

Meanwhile, fire up your smoker. I use a Browning charcoal-fired bullet smoker I acquired at a divorce garage sale [3], although an electric smoker allows for easier temperature control. I have also used a Weber grill with a two-zone set-up; however the temperature tends to get a little too high.

Soak a decent amount (a couple of handfuls) of wood chips in water. You don’t want to be too stingy. However, believe it or not, it is possible to get too much smoke. I prefer a mixture of oak and hickory for longer-term smoking. So do the eggsperts (https://www.masterclass.com/articles/how-to-select-smoking-woods). Do not use mesquite for this recipe, as it will overpower the other flavors (mesquite is best for short-term grilling, e.g. burgers). Large or small chunks will work equally well, as we won’t be smoking for hours on end.

TL;TMS: (too long, too much science) Place eight large eggs directly from the refrigerator into a large pot of boiling water for six minutes, and place directly in a bowl of ice water. If you’re bored, go outside, light your smoker and soak some wood.

[1] Water, being in between, takes some time to cross the membranes. This is largely why older eggs tend to float: water eventually passes out of the membranes to equilibrate with dry air (at roughly 4 mg/day) and is replaced with gases from the air. Hydrogen sulfide is also produced internally, both of which contribute to an increasingly large gas pocket, which in turn decreases the overall density.
[2] An old physics joke (https://en.wikipedia.org/wiki/Spherical_cow) actually applies well here! This neat derivation comes from Dr Charles D.H. Williams University of Exeter http://newton.ex.ac.uk/teaching/CDHW/egg/ and has been used as the basis for a number of egg boiling apps.

[3] I am convinced this has made my cooking taste sweeter. In the words of Marge Simpson: “Tears are the sweetest sauce”.

Lay the eggs evenly in your smoker, over a low temperature. As low as you can get it —while still getting decent smoke — with a pan of water between the heat source and your appetizing ovoids. If you can set it to 175°F (80°C), well that’s great.

Because I use a charcoal smoker, I put ice cubes in my water tray, to help reduce the temperature further because high temperature smoke will make your eggs rubbery. “Why is that?”

Well, I’m glad you asked!

Eggs are very high in protein, which are complex macromolecules — a whole lot of amino acids weakly bonded together. When you apply heat (or mechanical stress, or change the acidity) those weak bonds slip or break, so the proteins unfold, or denature. Hence the proteins act like billions of small rubber bands that get stretched out in the cooking process, forming a larger and larger network of denatured, rubbery, proteins.

How you like your eggs cooked comes down to precisely how you like your complex system of proteins denatured. I’m sure there’s a nerdy pick-up line in there somewhere.

Smoke for twenty minutes before turning and smoke another twenty. You should have a golden brown color over the whole surface.

At this point, you may halt if you are satisfied. If you’ve never smoked eggs before, then go ahead and just make smoked devilled eggs. They are so good. You can cash out here, take your winnings and leave. You have freshly smoked eggs!

If you’re still with me, then be warned: there’s no turning back. We are irrevocably entering the flavor frontier: we begin our descent into the Heart of Smokiness…

TL;TMS: Smoke on low heat for twenty minutes each side, until all sides are a light brown color. Remove immediately if the texture becomes rubbery.

Let the eggs cool.

Meanwhile, place the cold ground meat in a large bowl. Add the small amount of oil, as much of the diced onion as you consider civilized, and all of the dry ingredients with a pinch of salt. Mix well with a wooden spoon. Divide into eight equal balls. It might sound batty [1], but knead each meatball briefly. Doing this releases myosin, a sticky protein, when you massage it gently. Do it just enough so that it sticks to itself and not so much that it sticks all over your hands. If this isn’t making any sense, you can ‘take the L,’ and gently mix a whole egg into the mixture to add cohesion.

Cover each egg evenly such that no part of the egg shows. Knead gently so the mixture is stuck on nicely, producing an onion-studded meat-stucco spheroid.

[1] Forgive my indulgence, dear reader, as I now presume some liberties: our mutual descent towards a smoky utopia requires a certain level of complicity.

Add more wood chips (and charcoal if necessary) and increase the temperature of the smoker to 230–250°F (110–120°C). I remove the ice but keep the water-pan and use a kitchen thermometer to measure the smoke temperature just inside the closed lid.

Smoke for around an hour, turning each at around thirty minutes. You want the meat to still be tender on the outside. It should still have some elasticity if you prod it (gently!). However, you should resist the urge to frequently open your smoker to check. Trust your smoky instincts.

When done they should have a delicate pink concentric smoke ring.

While we’re waiting patiently, can we talk for a minute about how these pretty smoke rings are made?

The smoke ring relates to one of the main reasons smoking has been a food preparation method for millennia: preservation.

Among the gases produced by burning wood in a low-oxygen environment are various oxides of nitrogen (usually in trace amounts). Nitrogen dioxide (NO2) dissolves at the surface of our scrumptious bundles, forming nitrous acid (HNO2), which diffuses into the tissue, where it is converted into nitric oxide (NO). The NO then reacts with the iron atom in myoglobin, giving: a relatively stable, pretty-looking, pink molecule [1, 2].

This is one case where NO means yes!!!

Because the NO radical binds to the iron atom in the myoglobin, it prevents it from oxidizing further, which is the major cause of rancidity in tasty fats (nitrosation) [2], preserving the meat for much longer.

You will also get browning because the heme iron (in the ferrous state) is oxidized to the ferric state to make the usual brown color.

Why does smoking take so long? This is because the process relies largely on diffusion. Smoking food relies on the same process that causes a drop of ink to dissolve in water, although on a much slower time-scale. This process is quantified two related laws, known as Fick’s laws of diffusion [3, 4].

The first law relates the flux of the solute (NO) to its concentration difference and penetration (see equation above, the one with the J in it).

The second says that the rate of how much it spreads out is related to how quickly it penetrates [5] (the other equation, with the dC/dt).

For both of these, D is a constant for NO gas (2.60×10-5 cm2/s), C is the concentration and r is the radial distance into the Scotch egg.

In other words, the first says “higher concentrations will penetrate deeper” and the second says “it takes longer and longer as you get deeper”.

[1] McGee, H: “McGee on Food & Cooking,” Hodder and Stoughton Ltd, p.149 (2004). Please do yourself a favor and get someone to buy you this book if you don’t already own it!

[2] https://en.wikipedia.org/wiki/Nitrosation and https://en.wikipedia.org/wiki/Rancidification

[3] https://en.wikipedia.org/wiki/Fick%27s_laws_of_diffusion

[4] Zhou, L., Nyberg, K. & Rowat, A.C.: “Understanding diffusion theory and Fick’s law through food and cooking,” Adv. Physiol. Educ. 39:192–197 (2015)

[5] Interestingly enough, this is also the heat equation, if we consider temperature instead of concentration! This was the exact law used to determine the cooking time for the egg above in Step 1. Physics is wild.

On a high temperature, grill the smoked Scotch eggs so they have grill marks and look cooked, roughly five minutes each side, turning once. If you prefer, you may slather in BBQ sauce before doing so, and you will get carbonized sticky goodness.

Serve directly. Because of the effort involved, this is likely to be a showcase. Cut in half and serve with freshly ground salt and cracked pepper right on top of that perfectly textured morsel. The texture on the outside should have a slightly crisp shell, but the yolk should be sticky and tender. There should be a mild pink smoke ring in the meat, and also a ring just inside the white of the egg.

Enjoy! These do not last long.