Biochar Woks, Cooking, Collapse

I came back to my home city about ten years ago, after having lived for a few years up north in the Yukon. I took a culinary arts course at the college in Whitehorse, and spent some time working in the college's kitchen and at a hotel restaurant in town.

Whitehorse, YT

Strange as it was to move to a remote and isolated city to learn more about the culinary trade, instead of heading to some metropolis with a thriving restaurant scene, I feel it worked out well. No waiting list for the course, and tuition and rent were very reasonable. The hotel I worked in was part of Holland America, a stop on their bus tour line that ran from California to their cruise ships in Alaska. The sheer number of customers passing through the hotel, and the chaos of trying to serve them decent meals was a great chance to put into practice the ideas I'd picked up at school and from reading through cookbooks and culinary magazines.

That was a dark, sleepy winter of working weekends at the hotel, while taking the cooking course during the week and studying in the evenings for the test every Friday. I remember one December morning, working in the college bakery for a few hours, and looking out the window around 10am to see the sun rise over the snowy woods. The short daylight hours of course also meant that that sunset would be around 3pm, before we would get out of class.

A winter morning in Whitehorse, YT

Not too long after the term ended, one day in early spring the tour buses started arriving, along with a few new cooks and servers mostly from Ontario, and all at once we were swamped every dinner service, completely unprepared.

It taught me a lot. After getting spanked every night for a few weeks, I started trying to break down every station I worked on (grill, pasta, entrees) into a functioning system: writing up new prep lists for all the stations on the line with every single ingredient that was required of us. I decided on the minimal set of equipment for my stations to keep them clean, uncluttered & efficient, and a working method for every item, to make sure the dishes were ready to serve and not overcooked when the chef called for that table's food to be plated. I used what I knew of mnemonic systems to create some sort of physical marker for every dish the chef called out. Not all the stations had printed bills to look at, forgotten orders were a constant problem.

Arctic Char

We were required to come up with daily specials on the pasta and entree stations, and I used that opportunity to try out a lot of recipes and ideas. The chef there ordered a lot of fresh herbs & mushrooms, and fish like halibut and arctic char for us to work with. I've noticed in every establishment that I've cooked in, the chance for cooks to constantly create specials and new dishes is what keeps the heart of the kitchen alive, without that it becomes an assembly line with little space for human abilities to take root and grow.

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When I got back to Winnipeg, I struggled to find a kitchen that was like those I worked in up north. I was really disappointed with two of my first positions, working in the Manitoba Legislature and in a college residence dining hall, both of which had great kitchen spaces housed in beautiful, historic stone buildings, but at which the food quality was severely constrained. One of he first kitchens I came across that had a spark of independence and creativity was a restaurant owned by the student union on campus. It was re-opening at the time, after a renovation and expansion of the kitchen, and one of the new pieces of equipment was a commercial wok station, which I'd never worked on before.

The restaurant was managed by a tall, enthusiastic German man, who was passionate about cooking and hospitality and was a delight to work with. He had recruited a traveling German friend of his to help with the relaunch of the campus restaurant. His friend was a chef, also quite tall, with a thick beard, who had extensive cooking experience in Europe. He had spent time in Thailand, learning about their cuisine, and was knowledgeable of wok cooking in general. He had a lot of intense interests, from running marathons to working as a boat builder, so I picked his brain as often as I could, on culinary matters and many other things, he spent an inordinate amount of time volunteering his time in the restaurant.

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At that point, a few years after the financial crisis of 2008, I'd already steeped my brain in thoughts of peak oil and economic collapse for some time. I was actually surprised to have made it back to my home city at all before things all fell apart, as I imagined they might.

I had tried to think of ways that a culinary education might be to use in a collapse scenario: maybe I could study how many calories are needed for hard working people, and how these needs could be met with locally available foods? Maybe cooked en masse, in some sort of energy-efficient way? My ideas of what industrial collapse would look like were very rudimentary. I envisioned something like a quick-onset, severe economic depression, where communities would have to scrape together their resources in some sort of communal response to hard times. (Since then, the model of a long, slow decline, punctuated by periodic crises, seems like a better model for understanding recent decades.)

Wheat, meat, cabbage & ale

One thought I had: as cooks we tended to focus on the culinary styles of warmer regions, places like, say, Italy or Thailand, with ingredients like olives, lemons, coconut milk, tamarind, etc. Maybe, where I lived, in the prairies, we might be better to model our culinary styles on regions with a climate more similar to ours, based maybe with a lot of fermented cabbage and root vegetables and cereal grains?

I bought a few books on German food traditions. I asked that chef if maybe Germany might be a comparable climate to match the conditions in Manitoba, and he laughed and said Siberia was a far better match. (Alright, Russian cuisine it is.)

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www.graceyoung.com/

To get a handle on wok technique and to get some ideas for wok specials, I got a copy of Grace Young's excellent The Breath of a Wok. 

Young grew up in San Fransisco, her parents had recently emigrated from Hong Kong. She relates the deep impression left on her from her father's respect and enthusiasm for the Cantonese style stir-fry dishes. The book records her research into the history of woks and Chinese cooking, how they are made and how they are used, in Hong Kong and throughout China.

The title phrase, the breath of the wok, is a translation of the Cantonese phrase wok hay, which is used to describe a well-cooked wok dish: the elusive combination of the high-heat searing and the touch of smokiness this imparts, the fresh vegetables and meats, cut to the right size and added to the mix at the right time to give them just the right texture. The dish has to be served promptly, before the ephemeral wok hay begins to dissipate.

Young explains that hay is the Cantonese pronunciation of the character that is pronounced chi or qi in Mandarin, more well known to westerners, meaning both "breath" and "spirit", connoting the subtle energy that animates us. It's interesting that most ancient languages had a word that linked breathing to the idea of an subtle life energy: prana in Sanskrit, pneuma in Greek, ruach in Hebrew, spiritus in Latin. Chinese culture has long incorporated this concept of qi into daily life, with movement arts like qigong, with how one builds and arranges their living space, in how food is prepared. Young relates how her family would discuss the wok hay of a dish while eating out in San Francisco restaurants for special occasions.

https://modernistcuisine.com/

The deep, curved shape of a wok pan makes it versatile, ideal not only for tossing foods together, but combining many of the virtues of frying pans, skillets and deeper flat-bottomed pots. Along with stir-frying, they can be used for "pan-frying, deep frying, poaching, braising, boiling," and, when you add stacking bamboo baskets, they can be used for steaming and smoking. "It was staggering to realize that nearly the entire repertoire of Chinese cuisine can be cooked in a wok."

I'm reminded of how professional cooks in the west have traditionally employed an array of knives, from chef's knifes of several sizes, to a boning knife, a paring knife, a slicer, among others, while Chinese chefs (from what I've read) have tended to use a single cleaver for all their knife work. I like working with a full knife roll, but from an ecotechnic standpoint, I appreciate the economy with which the wok and the cleaver can accomplish so many varied cooking tasks.

What first struck my collapse-addled brain though was Young's descriptions of the pai dai dong, the Hong Kong version of open air food stalls, which were common when she'd visited the country as a child, but were disappearing when she returned as an adult to research her book.

The cooks could have such simple set ups: a folding table and some chairs, a heat source, a few ingredients, and they were open for business. It struck me then that, in some form of social collapse, something like this could be a way to make some daily cash. I've read a little about the collapse of the Soviet Union, and that book mentioned elderly women selling various foodstuffs in the street. The cash was only so important, it's value was tenuous in a collapse, but it was an impromptu way of distributing food and maintaining social relations in a struggling urban centre.

In a dai pai dong the food didn't have to be all that complicated. Young mentions that one of her favorite stalls was a chestnut hawker's, who cooked chestnuts in a wok filled with hot sand mixed with a little sugar. Each stall offered different types of dishes, all manner of stir-fries, noodles, pancakes, tamales, omelettes, fritters, and soups.

Young writes, in the early aught's, that food service regulations were making most dai pai dong illegal, though in some areas they would still "appear and disappear depending on the watchfulness of the local officials... these nightly street gatherings have an energy and a warmth made all the more attractive to me because of their chimera-like quality, appearing and disappearing right before my eyes."

The food market vendors weren't the only facet of traditional wok culture that was fading away. Young says that one used to be able to hear from the streets the hammering of carbon steel discs from small artisan shops who produced woks locally, before fire and noise regulations closed most of these shops down. Production had moved to factories in mainland China, where labour costs were lower. And the wok repairmen, who used to make house calls to patch damaged woks, had likewise been put out of work: "No one repairs a wok when a new one is so cheap."

When she left Hong Kong to tour through some rural areas of China, Young found more of the traditional wok culture she was looking to document. A village she toured had a large, communal wok stove, in the old manor house of the landlord who was overthrown during the Cultural Revolution. It had two giant woks, about 42" in diameter and 15" deep at the centre, set into round masonry ovens. Too big for one person to lift alone, on the day Young visited, women from the village were boiling soybeans in the large woks to make tofu. They also use them for fermenting sweet potatoes or rice to make wine. Her guide mentions that large woks like these can be used to feed animals, or to heat water for washing clothes or bathing.

From "The Breath of a Wok"

The other stove that interested me was the traditional hearth stove at the home of the rice farmer who guided young around these areas of rural China, a type that had been used for many centuries, since the Han dynasty. Made of brick, about 2.5 feet high, with a stoke hole at the base of a fire chamber, dry rice stalks could be fed in at different rates, as the cooking process demanded different levels of heat. It's efficient use of fuel had been "dictated by centuries of shortages and need... the entire workplace is a marvel of efficiency."

It the colder regions of northern China, it seems that woks tended to be set into masonry ovens, and used more for long-cooking braises and stews than the quick intense stir-fries popular in the south.

Apparently in the north there is not a colloquial phrase equivalent to the Cantonese wok hey. It's another interesting example of how food traditions rise out of local traditions: in the heat of Hong Kong, a quick, intense stir-fry, using a minimal amount of fuel is optimal, while in the north, where a fire in a masonry hearth stove keeps a home heated, it makes sense to use that steady heat supply to simmer meats and vegetables. In tropical climates, foods can spoil quickly, so cooking smaller batches from fresh ingredients often makes sense. In colder regions, where nature supplies unlimited cold air for much of the year, the remainders of a stew can be cooled and saved for tomorrow's meal.

Cen Lian Gen, The Breath of a Wok

When Young traveled to Shanghai, she came across the traditional wok craftspeople she had hoped to find, two brothers running a small shop that their father had founded seventy years earlier. They took a minimum of five hours to hand-hammer carbon-steel into what they call "fire iron woks." Young notes that it was hard, deafening work in a fairly rudimentary shop, but that their pans "are beautiful, with rich, dull, pebbled finishes and exquisite crafting. They are nothing like I have ever seen before."

The demand for handmade woks had been decreasing over time, especially as western foods and modern cookware became more popular in China. The shop, operated by the brothers Cen Lian Gen and Cen Rong Gen, still had steady business with Shanghai's top restaurants, who appreciated the strength and durability of the individually made woks. After Young's book was released, Williams-Sonoma began to sell their woks in the U.S.

The shop closed in 2016, as the neighborhood was slated for demolition, making way for new construction. When asked if he worried about the future of his craft, Cen Lian Gen replied that "people are too busy and they have less time to cook. But I don't worry about the fate of the wok. A good restaurant will always use a traditional carbon-steel fire-iron wok."

Two of Grace Young's woks, 16 yrs. old and brand new

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From "The Breath of a Wok"

One image from Young's book stuck in my mind, a photo of a wok sitting on a pail of charcoal, cooking what looked like a simple mix of cabbage and bell peppers.

I think when a person first starts taking seriously ideas of social and economic collapse, part of the process is imagining what you might do if things fell apart really quickly. Some people hold to these rapid collapse scenarios, others modify their vision to encompass a drawn-out, protracted decline, and still others, after a few years of preoccupation, tire of the subject and move on.

One of my earlier fast collapse imaginations was sparked by this picture of cooking over bucket of coals: I envisioned attaching a small trailer to the industrial-grade bicycle I'd bought from Worksman Cycles, USA, and riding it through the quiet morning streets, to pick up some fresh vegetables and meats to add to the cooking gear I would be hauling to set-up on some busy street corner. I suppose I'd have had to pick up charcoal from somewhere occasionally, I guess from some small scale charcoal maker, traditionally called a 'collier'. Charcoal-makers would heat pieces of wood in a low-oxygen setting, driving off volatile substances to leave behind the chunks of black carbon that people could ignite again in their stoves, to cook over the even, fairly smokeless heat.

How I imagined there would be daily farmer's markets and enough street traffic of workers passing by to be customers, I'm not sure: one's brain only has so much computing power to envision how a quick collapse scenario would affect an entire society. The idea of a charcoal street wok was just one among several others. I pictured using wet stones to sharpen knives, scissors and other larger blades, and getting a grain mill so that I could store grains and bake whole wheat bread.

Biochar made from sawdust pellets

Time passed, and no total materialized. Eventually I transitioned out of working as a cook and got into plumbing. An interest in climate change, however, returned my thoughts to charcoal, as I read about the subject of biochar. In a nutshell, biochar is made by heating organic materials, such as tree branches or corn stalks, in a set up that greatly limits the amount of oxygen that reaches the materials as they bake.

This leaves behind char that is largely carbon, in a form that won't break down and return the atmosphere for hundreds to thousands of years. It can be mixed into compost and returned to the soil, or mixed into materials like mortar or plaster and sequestered into the built environment. This allows the next generation of trees and plants to draw down more carbon from the atmosphere over the following season.

I tinkered with some small biochar retorts, using paint cans and coffee carafes, to get a feel for how biochar was made while I read about the subject. Looking at videos about the common larger kiln design, made from 55-gallon barrels that small scale farmers tended to use to produce biochar for their themselves, they almost always commented that ideally they'd like make use of the heat produced when making the biochar, for something like cooking.

Clay Biochar Model Kiln

The only examples I'd seen attempting this this were some pictures of clay biochar cook stoves being made in Africa, and I couldn't find any instructions for these. I tried to design my own clay version in a pottery class I was taking, with ring pan fitting around the chimney. It didn't work that well, the heat rose too quickly through the chimney.

I still had in mind that idea of a wok set over a barrel of burning charcoal. I thought that a wok burner that used the heat from the process of making biochar would be interesting. Instead of wasting the heat used to make charcoal, and then using the charcoal to cook food, emitting carbon dioxide in the process, this cook stove would use the heat from the char making process. The char would then be used to sequester the carbon, adding it into compost and then back into the soil, hopefully improving soil fertility in the process. Every time you cooked on it you'd engage in a cycle of drawing down carbon from the atmosphere.

Stacking up the component pieces

I found some 15 gallon drums that seemed about the right size to have a wok sit above them at about torso-height, and the project came together fairly easily from there. (I'll include some pictures showing how it was assembled as a post-script to this.)

Basically, there's an outer drum with holes drilled around the base, and then a smaller metal container inside to hold the dry organic feedstock and keep it mostly out of the air-stream in the drum. Into the lid of the drums I inserted regular galvanized steel ductwork fittings to serve as the chimney, increasing the diameter size from 6" to 8" at the top, for the wok pan to sit inside.

These stoves work on a basic TLUD design (Top Lit Up Draft): the flames are at the top of the container, and hot, narrow chimney creates a natural upwards draft that keeps the airflow rising around edges of the inner chamber of the feedstock. This keeps oxygen from readily combining with the carbon in the organic materials. The nice thing about TLUDs is that you don't need a separate fire to pyrolize the dried materials: the flames in these sit just above the feedstock, and radiate heat downwards into the materials to keep the volatile gases coming. The rising current of air from the holes at the base ignites with the volatile gases, and whisks the exhaust up and out the chimney.

I used a Y-fitting on chimney of the first stove I made, as I thought I might need to maintain the upwards draft, I thought perhaps the wok pan would prevent proper air flow. I found this lost too much heat out the Y, it didn't produce the blistering fire needed for proper wok cooking. Grace Young explains:

When a wok is not scorching hot, food cannot be seared and a stir-fry becomes watery... with good wok hay, vegetables have a crisp texture the Cantonese call song, highly valued in Chinese cooking... (p. 63)

On the next stove I made, I omitted the Y-fitting and drilled holes in the 8" fitting that the wok sits in, and this worked wonderfully, the wok fire was extremely hot and close to the base of the pan. The two stoves work well as a team though: the hotter red one is great for a proper stir fry, and the cooler black one is a good temperature for cooking a wok-full of rice, slowly braising meat or simmering a thai coconut curry sauce. It's about as easy to light and tend to two stoves as it is one, and you've sequestered double the carbon by the end of the session.

The easiest fuel source for me has been sawdust pellets, a waste product of lumber production. Being just compressed sawdust, there are no adhesives or chemical binders to worry about ending up in garden soil. I've used 2x4 cut-offs and even added in pistachio shells, to see how they would char. I would like to start collecting up twigs and branches to make into biochar. My idea is to dry batches of them in the solar dehydrator I made last summer, removing these screened trays and just stacking them inside to dry in the current of warm air.

These stoves are, to some extent, a novelty. I am not positing them as any sort of solution for climate change, of course. I made them to get a better feel for the process of pyrolysis and to help promote the idea of biochar, though kilns of these size could easily produce enough char for a backyard garden, if it turns out that mixing biochar into compost is a worthwhile soil amendment.

https://www.chelseagreen.com/product/burn-paperback/

Biochar can be made at different scales however: I envision it being produced in suburban backyards, on small-scale market farms, on municipal lots near the where cities compost the branches and trees they cut down, and then again in large industrial plants on a regional level. I think of biochar as being a subset of "carbon farming", one of the various ways we can increase the amount of carbon that is stored in the earth, to accompany other practices like reforestation and afforestation. Project Drawdown lists biochar as #72 in their list of the top one hundred methods of reducing the amount of greenhouse gases in the atmosphere. Albert Bates and Kathy Draper have recently released a fascinating book that details the wide range of projects people are innovating to make and use biochar, that I'm looking to review in an upcoming post.

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I wrote most of this essay before the coronavirus outbreak had become a pandemic. It's surprising how much the current context alters how I'm reading the pieces I was working on even a few months ago. On social media and in podcasts, I'm hearing discussions of decline and collapse from people who I wouldn't have expected to consider the idea. I don't think anyone really knows how all this is all going to play out, but the speculations run from moderate to quite dire.

https://newsociety.com/books/g/green-wizardry

I'm not a "prepper" at all, at least not by any normal understanding of the word. Despite all the reading and ruminations that have occupied me on these topics, I haven't managed to position myself for periods of crisis much better than the average city dweller: I've got no homestead, no garden, no substantial pantry. However, in reading about topics related to sustainability and resilience, I'm trying to build up skills that might possibly be put into use at some point down the line. Working on small projects like the biochar woks keeps me engaged in these issues. I think it is a way to process information and emotions about the predicaments that face us, and better imagine how we might adapt and respond.

I've noticed my own imaginings of the future becoming less dire over the years though. I'm still expecting to see industrial decline, various resource shortages, increasing climate disruptions, but I'm picturing it as a long process that we will ultimately adapt to, and hopefully mitigate, if we are wise. My focus is on learning about helpful skills and practices, and working to bring them forward into the future.

For these wok stoves, I've imagined setting them up at a local farmer's market and cooking stir-fries, beside a booth with information on biochar and appropriate technology. Maybe we could use some fresh vegetables and meats from the market, and farmers could take the biochar with them at the end of the day, and we could raise some money for a local group working to help the community through all of this.

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Construction Steps

I had in mind a general design like this, and then started modifying the parts so that they'd work as a wok burner.

















I found some metal drums that seemed abut the right height, about 30" tall.

The first step was to drill some holes all around the base of the drum. These allow air into outer chamber of the retort, to rise up and combust in the flammable gases above the organic materials, and then drawn up and out of the hot chimney.














Next, I added some three long bolts facing into the centre of the barrel, which would serve as an inner shelf for the container of woody feedstock to rest on.

To hold the feedstock for the biochar, I found these containers in a local garden centre. I drilled a bunch of small holes, evenly spaced, through the bottom of the pail.

These allow a small amount of "process air" to enter the inner chamber, while the majority of the air in the drum rises along the outside of this pail, warming before it ignites above the feedstock.

The small flow of process air allows the natural upward draft to quickly draw up the flammable volatile gases from the woody materials as they heat.

I took another one of these containers, turned drilled holes around it's base, and used tin snips to cut a round hole in the bottom of the container, for the chimney to fit into. This second container gets flipped over and used as a lid for the inner chamber, filled with biochar feedstock.



This one is filled with sawdust pellets, though I have used lumber cut-offs and even pistachio shells since then.














Next, I drilled a circle of holes in the drum lid for the chimney to fit into.

I cut through these holes with reciprocating saw, and bent down the metal. This actually worked well to hold the chimney in place.














The 6" ductwork coupling fits inside the hole in the lid, and then the 6"x8" reducing coupling was fit over that.

Holes are drilled around the top to let the exhaust out and maintain the natural draft once the wok is placed on top.

I added six eye bolts and some thin aircraft cable in a tripod arrangement to give the wok more stability during use.

Unnecessary step: filling the gap between the chimney and lid.

I first tried some high heat gasket maker - which caught on fire once the kiln reached full temps!

Next tried "waterglass," which you can make by heating a solution of lye and silica in water. That creates a clear, sticky adhesive, which I mixed with masonry sand and molded around the base of the chimney.

The high heat set the waterglass and sand and sealed up the gap.

Last I sprayed the lids and chimneys with Tremclad High Heat Enamel paint to prevent them from rusting.

I found this 14" Lodge Cast Iron Wok on clearance when Hudson's Bay Home was clearing out it's inventory. Not necessary at all, but it's sturdy and does a good job at diffusing the heat.

Grace Young notes that in China, besides the carbon steel woks shown in the photos above, cast iron woks are also traditional, but they are not like Western cast iron pans. They are thin, and smooth, apparently you can shatter them if you were to smash them against a hard surface.

Besides sawdust pellets, which pyrolise nicely and evenly, I've tried making biochar from 2x4 cut-offs, which also worked well, but was a little more difficult to get started.


















As an experiment, I tried charring pistachio shells, just because they were already dried and easy to collect up.

I kept the in a separate can for the trial just have a sample of charred shells separate from the wood, but normally I'd just mix them in with the the sawdust pellets.

They wouldn't support the initial combustion to get the pyrolysis process going, but mixed among other combustibles, you can collect up the carbon in all sorts of dried organic materials.