Eat Carbon Credits or Carbon-based Foods?

We all have read or heard about Carbon Credits, and other Environmental Credits accruing to Big Business... but I don't really understand all the logic in them. If an industrial plant produces too many greenhouse gases, it seems they can simply buy carbon credits from someone doing a better job for the environment, and continue polluting. I think partly it's just another shell game in financial manipulation, because it surely hasn't improved the air quality, ozone layer, global warming and greenhouse gases that I can see. 

There's a lot of talk encouraging us all to reduce our "carbon footprint" (and some of us do) but somehow I don't think we will run out of carbon based fuels (wood, oil, coal and natural gas) before mankind makes it almost impossible to grow anything edible on this lovely blue planet. Human beings are carbon-based, and our foods are carbon-based. How does buying and selling carbon credits help us grow more and healthier foods and live a healthier life?

On the other hand, burying small bits of carbon (natural charcoal, NOT charcoal briquettes) in my garden certainly improves the health of the soil, and lately I see many more earthworms and other visible organisms. (I can't see the gazillion others without a microscope.) I'm also beginning to see more and healthier production in the very earliest beds I amended with biochar 5 years ago, and I finally feel like I'm getting to be a better steward. Bits of carbon in the soil sequester carbon dioxide, which plants need to grow and produce fruit, grain or flowers. Sometime back, I wrote a piece on Biochar for DavesGarden.com. Reading it will give you some background if biochar is unfamiliar to you.

Our nearby land grant university got a grant of several million dollars to build a pyrolysis unit to burn factory (CAFO) chicken house waste into biochar about 3-4 years ago. The problem for me is that the biochar they made was such fine powder that most of it blew away during the demonstration I saw, long before it could be incorporated into the topsoil (even on a day with very little breeze). Plus, it was dirty and nasty to breathe that black dust while it was being applied.

I have a wood burning stove as my back-up emergency heat, although I seldom need it much. The small bits of charred wood left among the ashes are filtered out later and scattered across my garden. (I break them up with a hammer if they are larger than a walnut, but it's dirty work.) Since I don't till anymore, I cover the bits with a thick layer of compost and within a year or two it all becomes part of the soil, loose and fertile. Eventually that soil will be many inches deep, rather than the scant layer of topsoil that hasn't washed into the creek over many, many years! I don't walk on much of my garden, so it's not compacted other than on the paths.

Mini Retort for Charcoal/Ash

I'm in the planning stages for making a variety of cheeses, and getting my list together of ingredients like starter cultures, aroma-producing bacterial and yeast additives, colorings, and even some ash used in a goat cheese like Humboldt Fog. (Who could resist a name like that?) Ash is basically activated charcoal, and easy to make at home in a semi-retort. One less thing to buy!

In the chemical industry, a retort is an airtight vessel in which substances are heated for a chemical reaction producing gaseous products to be collected in a collection vessel or for further processing. A retort is also used to make charcoal to burn in a small forge. I have a homemade retort for making charcoal, which I inoculate and use as biochar for my garden. However, it is a 30 gallon drum inside a 55 gallon drum... far too large for making ash for cheese, and I really does not capture the gases to use as fuel for the burn in process. (That type of process is described here.)

What I want for making food-grade ash is a miniature retort-style container that will drive off the gases and totally char the wood inside. Then I can grind the char into a powder via a spare coffee grinder for later use in my cheese. 

I bought a new, clean paint can, quart-size. (I may need to upgrade to a gallon size after I see how this works.)

The wood of choice for this type of ash is a fruit or nut wood or grape vines, and I had some branches available from pruning an apple tree. They do not have to be totally dry although that is best; green wood cuttings just have a higher moisture content that will still be driven off, just requiring more time and fuel for the fire itself. The retort needs to be stacked as tightly as possible to eliminate a lot of oxygen (which creates pressure inside the can when heated) from the get-go. Then the lid needs a small hole to let the heated gases escape (and prevent the can from blowing up!). I made a 3/8" hole, which may be too large, but I won't know until I try it.

Now it's prepared for the next time I build a fire, when I will put the tightly closed can on the fire/logs/coals so that I can watch the vent. When the can contents get red hot, the vent hole will start to smoke, and soon the smoke will turn to white. The water content will start to be driven off at 212ºF, and the wood will start to char at around 500ºF. After some time, maybe an hour or more depending on the temp of the fire and the moisture content inside the can, the white smoke will stop entirely, indicating all the volatile gases have been driven off.

The next step after you think the wood had charred sufficiently, is remove the can from the fire with fireplace gloves or tongs and set on a fireproof surface to cool at least 24 hours. Now it should be ready to crush and grind to a powder.

Later: I finally 'fired' the can of twigs, with only moderate success. Here just above you can see the fine smoke beginning to trail out of the hole in the can lid.

I apparently did not have either a hot-enough fire, or too small a fire... the twigs charred appropriately on the bottom, but not all the way up to the top, even though I left them on the burning briquettes and embers overnight.

Now that I'm thinking about that particular fire, I remember I used briquettes from the same bag last fall for my first cold smoking, and they produced only a very short-lasting heat. When the briquettes became covered with ash, they cooled considerably. To fully char these apple twigs, I'll apparently need build a hot wood fire to char the apple twigs.

If all else fails, I can always buy ash, but I'm NOT giving up yet!

Biochar Field Day

I have been using, and writing, about biochar for several years, and I think I am starting to see some improvements in my own garden. Recently I had the opportunity to attend the "Biochar Field Day" workshop in the next county south of me, and want to report what I found interesting.

Biochar has been around for 2500 years or more, but largely unnoticed until recently. Terra Preta de Indio (or Indian Black Earth) is a Pre-Columbian dark earth mass re-discovered in the Brazilian Amazon region and several other countries in South America a few years ago. The soil is incredibly fertile, and contains charcoal (biochar) that has been there almost forever. Even though Biochar has received a lot of interest in the last few years, there have been very few documented studies that I've seen. 

I was suitably impressed with this event, not just by their demonstrated results after 2 years of trials (which I expected), but by the the overall project. 

The Virginia Tech Biochar Trials, headed by Dr. Rory Maguire, has developed a working prototype pyrolysis unit that can convert 4,000 pounds of waste poultry litter a day into some useable products. 40% is captured as high-value pyloric oil suitable for many purposes, perhaps like a heating oil; 40% is converted to a powdery biochar useful to help increase soil fertility, and the remaining 20% is mostly bio-gas, used as part of the fuel for the machine.

The speakers included Dr. Maguire and a couple of his grad students, Dr. Julie Major of the International Biochar Initiative who came down from Montreal (Canada), and Dr. Allen Straw, our very knowledgeable area rep from the Virginia Extension Service. Half he trials were done on the farm of Anthony Flaccavento (Abingdon Organics) where the workshop was held, and the other trial on another field several miles away belonging to Dr. Richard Moyer, who is my favorite egg man at the Abingdon Farmers' Market.

I am really pleased to see someone is making something useful from commercial chicken house litter, rather than just a stinky dump pile. Since I know I personally wouldn't use chicken manure from a commercial operation on my garden, I asked about contaminates from the litter. Dr. Maguire said the temperatures of the pyrolysis unit are so high that it kills any organisms that are in the waste. I didn't ask about other contaminants like heavy metals that might be in the feed.

I crush the biochar I make to about pea-size to use in my garden; it is far less messy than the bucket of powdered biochar demonstrated at the workshop. When they transferred the biochar from one bucket to another, a large cloud of dense black particulates hovered, and a good bit was carried away with the wind. Applying that fine powder on a field would mean tilling it in immediately, and even then there would be considerable loss from the mechanical action and air movement.

Something else I do with my biochar that they did not, is to inoculate it. I started using some fresh urine, which has a urea content of about 3-4%, as an inoculate. (Commercial urea is about 40% and will burn plants.) It helps feed the soil microbes. Next year I plan to inoculate my biochar with some EM™ (living microbes) and probably some fish emulsion.

Some of the group were totally unfamiliar with biochar, and I described adding plain crushed biochar to my garden as 'salting the soil with condos for the microbes'... and when I add inoculated biochar, I'm adding 'condos fully furnished, and with food on the table'.

One lovely couple in attendance are hosting a 5-weekend Permaculture Certification Course next Spring (as part of their "Help Build Community Resilience" efforts) and have asked if I'd do a workshop on building an inexpensive backyard burner for making biochar. Of course I'm delighted!