A chipotle pepper is a jalapeno that has been smoked, a food preservation method as old as agriculture itself. With a bumper crop of jalapenos, pimentos and roasting peppers in need of attention, I smoked two batches of peppers in my biochar trench, with wonderful results. Here’s my report.

The Site

Last fall, I dug a 1.5-by-8 foot trench in an area that had been overrun with perennial weeds. During the winter, I partially burned two small mountains of brambles and other hard-to-compost woody materials. This summer, I grew a successful crop of winter squash in the refilled trench, and reopened it for my pepper smoking project in mid-September. Some folks disapprove of all open burning, but I think most rural homesteads need a safe place to burn stuff from time to time. At our house, we’re experimenting with filling this need with a thoughtfully managed and monitored biochar trench. The terra preta soils of the Amazon, upon which the concept of biochar is based, were created over many centuries of successive smoulderings, so I am curious as to the long-term effects of fire in the hole.

The Fire

You can smoke peppers in a covered grill or smoker, but we don’t eat much meat so I have neither.  Smoking peppers calls for a cool fire that flavors and dries the peppers (as opposed to cooking them), so I built a small fire in the middle of the trench, and placed pairs of bricks covered with aluminum foil (for cleanliness) at both ends to hold my trays of peppers. I used apple wood saved from pruning, but you can also use hickory, mesquite, or other aromatic woods.    

Once the wood was burning well, I partially snuffed the fire with soil, placed the trays of prepared peppers (see below) on the bricks, and covered the trench with a piece of metal roofing. An hour or so later, when I saw only faint wisps of smoke coming from the trench, I restarted the fire with fresh dry twigs and a little more wood. My peppers got a total of three hours of smoking time.

The Peppers

In my first batch, I smoked large strips of jalapeno, roasting and pimento peppers on heat-proof roasting pans. There was no need to oil the pans (the peppers didn’t stick), but I did cover the peppers loosely with aluminum foil. This was mostly to shield them from scattered dirt as I moved the metal cover on and off. It would not be necessary in a smoker or grill.

After smoking for three hours, I continued the drying process in my food dehydrator. The big pieces curled so much that uniform drying was going to take a long time, and I didn’t want to lose smoke flavor from prolonged drying. Besides, the half-dried sweet and sweet/hot peppers tasted like mouthwatering veggie bacon, so I stopped at the half-dry chewy stage and stashed the peppers in the freezer. For my second batch, I cut jalapenos into rings one-third-inch thick. The rings seemed to absorb more smoke flavor than the strips, and they dried faster, too. Within a few hours, the chipotle rings were ready for cool storage in glass jars.

The Drying Process

Finishing off smoked peppers in your dehydrator is a very aromatic process best done outdoors. And please be advised: The smoke smell will linger in your dehydrator, even if you give it a good cleaning as soon as you are done.  The campfire fragrance will wane after a few days, but why fight it? The batch of spiced apples I dried after the smoked peppers filled the house with the combined aromas of cinnamon and barbecue — of the most delicious aromas of the food preservation season.

Barbara Pleasant 

Josh Frye raises a lot of chickens — as many as 800,000 birds a year. A lot of chickens means a lot of chicken poop to dispose of, plus the need for a lot of propane (about 30,000 gallons a year) to keep the chicks warm in the winter. So when his buddy, Matt Harper, suggested they take a road trip to Illinois to see a gasifier that would turn poop into heat, Frye was interested.

The machine at Southern Illinois University made a good impression on Frye. The fixed-bed gasifier processed five tons of poultry litter an hour with no smell, no smoke and no internal moving parts.

Frye decided to procure his own gasifier. He worked with Southern Illinois-based Coaltec Energy to identify a technology that best met his needs, and settled on the fixed-bed gasifier produced by Westside Energies of Canada. Coaltec is the U.S. sales representative for Westside Energies, and the companies helped him apply for grants to purchase and install the unit (approximate cost, $1,000,000).

The gasifier.

PHOTO COURTESY INTERNATIONAL BIOCHAR INITIATIVE

Things fell into place as grants and low-interest loans came through from several West Virginia state agencies. After the grant writing was completed, the price of metal suddenly spiked, increasing the cost of the gasifier. Westside and Coaltec kicked in a contribution to keep the project within budget.

A more welcome surprise came for Frye when he was introduced to the concept of biochar by Tom Basden, an extension specialist in nutrient management at West Virginia University. “Tom told me I would end up growing chickens mainly for the poop,” Frye says. “I thought he was off his rocker, but now I think he might be right on the money.”

Frye is now producing a high quality biochar and has sold his first ton at a net price of $480 ($600 a ton for the char and $120 a ton transport costs) to a farmer in New Jersey who is testing its qualities for his crop of corn and soybeans. A farm in South Carolina is testing the char on pharmaceutical grapes (used in the nutritional supplement industry). Frye worked with International Biochar Initiative (IBI) board members Johannes Lehmann and Stephen Joseph to optimize the gasifier to produce quality biochar rich in phosphorous and potassium. His test burns so far have made biochar that ranges from 1.7 to 3.2 percent phosphorous and 5.4 to 9.6 percent potassium.

Josh Frye explains the gasification process.

PHOTO COURTESY INTERNATIONAL BIOCHAR INITIATIVE

Biochar promises to add an impressive income stream to his operation, but it’s not just about money for Frye. He had been concerned that his waste-to-energy gasifier was going to destroy the fertilizer value of the poop he had been cleaning out and selling to local farmers for about $5 a ton. “Now I feel like I am making a real contribution to the ag world,” Frye says. “Taking a raw material and converting it into a stable carbon-rich product is a great thing. Talk about falling in the poop and coming out smelling like a rose!”

Frye Poultry’s annual production of 125 to 600 tons of poultry litter can generate an estimated 25 to 120 tons of biochar. From his initial testing of the char, Frye found that depending on the operating conditions, his gasifier produces biochar with an organic carbon content ranging from 10 to 34 percent. The carbon content is largely dependent on the moisture content of the poultry litter. With lower moisture contents, the carbon percentage in the biochar increases.

The 30-foot-by-50-foot fixed-bed gasifier was installed at Frye Poultry in March 2007. It operates with negative pressure so it can burn at lower temperatures and produce biochar concurrently with energy. The unit has a maximum feed rate of about 1,000 pounds an hour, which can produce five million BTU of energy. Burning up to 12 tons of litter per day, it can produce 3 to 4 tons of char a day.

Char from the gasifier

PHOTO COURTESY INTERNATIONAL BIOCHAR INITIATIVE

Coaltec staff is able to monitor performance of the unit from their offices in British Columbia, Canada. Frye operates the gasifier single-handedly at his West Virginia farm. It took Frye roughly five burns over three months to feel competent in the operation of the unit. Coaltec representatives visited onsite to help with these initial burns. One of the biggest hurdles for Frye — a dedicated Macintosh user — was learning the IBM-based computer programs to operate the gasifier.

In the winter of 2007-08, Frye ran six test burns testing wet or dry litter with or without adding wood shavings or chips. He has run the gasifier in a continuous steady state mode for up to 10 days. He has determined that one burn per cycle of broilers is ideal, with a continuous operation period of about three weeks to warm the poultry houses up to 90 degrees Fahrenheit for hatchlings, tapering off to 70 degrees.

The initial funding covered much of the installation and first year of operation. But Frye realized that to continue a viable operation, he needed to have a structure to store and dry the chicken litter. Wet litter significantly slowed the process and was less efficient. Frye received additional grant funding through MicroUnity to build a storage area.

Last year’s test burns produced about 30 tons of biochar and saved Frye about four thousand gallons of propane. Eventually he expects to reduce his propane consumption by 80 to 90 percent. He is also looking into using the gasifier heat in the summer to operate a chiller to cool the poultry houses.

Frye is happy with the unit and appreciative of all the help he has received from Coaltec and others. And he’s become accustomed to surprises because they keep on coming. Frye gave some biochar to his neighbors to play with, and one neighbor “cussed him,” he says, because the grass growing on the biochar was so thick it tore up his hay mower. “Looked like he gave that pasture a punk rock haircut,” Frye says, “He needs to get more horsepower and sharpen that mower blade.”

January 23 through 25, 2009, about 100 “stovers” gathered in Kirkland, Wash., for the annual ETHOS (Engineers in Technical and Humanitarian Opportunities of Service) conference devoted to meeting household energy needs in the developing world. Improved stove technology was only part of a program that included discussion of standards and testing, distribution and manufacturing, and the intricacies of carbon credit financing. The highlight of the conference occurred at the ceremonial “lighting of the stoves” on the concrete steps outside the conference hall under a light flurry of snow late on Sunday afternoon.

A variety of innovative designs were on display, but only two of the stoves were able to operate in a pyrolysis mode to produce charcoal. Paul Anderson, an independent stover who works with the Biomass Energy Foundation, demonstrated a TLUD (top-lit updraft gasifier) stove using natural draft that leaves a charcoal residue after cooking. The char can be saved by dumping it into a covered bucket or pot to stop combustion. Anderson has two versions, what he calls the “refugee” stove made of tin cans, and the “artisan” version that will be manufactured in India. Plans for constructing the stoves will be freely available soon on the bioenergy listserve.

PHOTO BY KELPIE WILSON/INTERNATIONAL   BIOCHAR INITIATIVE

Paul Anderson's "artisan" top-lit updraft (TLUD) gasifer stove   produces charcoal at the end of a cooking session that can be   saved in a covered metal bucket or ceramic pot.

Biochar advocates at the conference were very intrigued with the Lucia stove invented by entrepreneur Nat Mulcahy of WorldStove. Mulcahy is an industrial designer who has thrown himself into the project of bringing a sophisticated, high performance biomass stove to mass markets worldwide. Contrary to the approach of many stove designers who search for designs that can be easily manufactured in poor countries, Mulcahy wondered what could be accomplished using advanced manufacturing technology. He found that metal injection molding allowed him to make a burner with a swirl pattern resulting in highly efficient combustion and heat transfer. When used with a fan, the stove can be operated in a pyrolysis mode that produces charcoal. You can see his pyrolysis demonstration at the WorldStove YouTube channel.

PHOTO BY KELPIE WILSON/INTERNATIONAL BIOCHAR INITIATIVE

Nat Mulcahy prepares to add fuel to his Lucia stove. The copper pot can be set on   top of the stove to function as a space heater.

Mulcahy’s burner is made out of 28 recycled aluminum cans. An aluminum inlet plate and a cast-iron forge plate complete the list of special parts; the rest of the stove can be put together from sheet metal, common fasteners and fans recycled from computers. The parts can be shipped flat and assembled locally. WorldStove plans to start production at a factory in northern Italy in March. The stove has been certified in Europe as producing less than 66 ppm carbon monoxide, and WorldStove is pursuing licenses to manufacture a model that will work as a fireplace insert, along with another model that Mulcahy says will triple the heat output and halve the emissions of a standard pellet stove. He also announced that Finland wants to subsidize 1.5 million of his stoves for saunas with the objective of producing biochar.

The new Biolite stove by industrial designers Jonathan Cedar and Alec Drummond does not make char, but is interesting nonetheless. A lightweight backpacking stove, its key innovation is to incorporate a bismuth-telluride thermoelectric generator (TEG) to operate a forced-air draft fan for this gasifier stove. The TEG is a nice innovation that could be applied to biochar producing stoves that use fans, eliminating the need for any external power supply.

PHOTO BY KELPIE WILSON/INTERNATIONAL BIOCHAR INITIATIVE

Prototypes of the Biolite backpacking stove designed by Jonathan Cedar and   Alec Drummond. The fan is powered by an integrated thermoelectric generator.

Aside from exciting new technology, the Ethos conference offered many sessions concerned with the problems of stove dissemination. More than 1.5 billion people still cook over open fires. Impacts to health, safety, forests, air and climate could be mitigated with better stoves, but lack of funding for stove programs is a huge barrier. Carbon credit financing can help.

Two groups shared information on ways to obtain carbon credit financing. Stuart Conway of Trees, Water and People explained the process his group went through to offer a direct voluntary offset for its programs. The Center for Entrepreneurship in International Health and Development (CEIHD) is available to help groups set up projects for carbon credits. Adding biochar production to a stove program can potentially increase the amount of carbon offset achievable, and internationally there is a growing interest in biochar-producing stoves.

In December 2008, at the climate meeting in Poland, The International Biochar Initiative (IBI) held a side event on stoves that was very well attended. See the description of this event on IBI’s Poznan page.

Standards and testing are topics that are also of concern to biochar producers. Aprovecho Research Center had a large presence at the conference and stove designers will want to take a look at all the resources they offer. Laboratory manager Nordica MacCarty had Aprovecho’s mobile emissions testing unit on display. The unit packs up into one large suitcase that can be taken into the field. MacCarty has done testing in India and is off to Africa next. Aprovecho also does emissions testing at their lab in Cottage Grove, Ore.

Many interesting discussions took place in the hallways and at meals. A small group of biochar enthusiasts discussed ideas for helping less fortunate people generate income by producing biochar. Other discussions heard at the Ethos Conference repeated this theme of providing income-generating solutions. The practical aspects of integrating appropriate technology into people’s lives emerged as perhaps the greatest challenge, whether in the developing or already developed worlds.