Phil Stevens

I had a lovely gentle Black Orpington rooster named inigo Montoya. His father, on the other (five-fingered) hand, attacked my son in the paddock one day, and so the tale is told.

A while back I bought 100 used coffee sacks. I think they cost me $20 plus shipping and it's one of the best micro investments I ever made. Sometimes when I got out a fresh bag there would be a handful of green coffee beans left in the bottom, so I got to wondering about how to make the most of those.

I got out my cheapo heat gun and a stainless steel colander, and went to work. The results were impressive, and I learned a few important things:

1. Always do this outside. The smell is not all that nice thanks to the skins coming off the beans and burning.

2. The skins fly around and go everywhere.

3. Keep the beans moving around and watch for the oils to accumulate on the surface as well as the colour. This is how you control the darkness.

4. Don't try to do too much at once. My best batches were a couple of handfuls, maybe a cup at most.

John Suavecito wrote:Phil,
I have a lot of clay soil where I live. Would it be helpful to add some clay soil to the wood stock before I start the biochar burn?  The functionality sounds like a good way to improve soil fertility.
John S
PDX OR

Yes, this is a great idea. If you're ambitious, try making a clay slurry and soaking a batch, then letting it dry out prior to a burn.

Jay Angler wrote:

Does the article say how long the ~300 degree biochar lasts? One year - 50 years - 300 years? Because I consider it a renewable resource on my land, if the low temp stuff I can make easily and that helps my soil, can last even 10 years (and I suspect most of it lasts longer than that), I think I'm still ahead so long as I keep making it.

Lower-temperature biochars oxidise and degrade more quickly than high-temperature ones. But it's like a long ramp, not falling off a cliff. Let's say we had two batches of biochar made from the same type of wood, one produced at 300 degrees and the other at 700, and put them into soil.  The total carbon stored starts off at 90% for both types, and if you sample at 100 years the 300-degree batch might be down to 60% and the 700-degree batch is 85%. At 200 years they're at 50% and 80%, respectively, and at 1000 years the numbers might be 20% and 60%.

Aside from giving up some of its carbon, the pore structure of biochar more than a few decades old gets plugged, so if you've got plenty of feedstock and like the results, there's a good incentive to keep topping it up. The terra preta soils probably developed over centuries at least, and deposits of pyrogenic carbon in ecosystems with recurring fires often go back tens of thousands of years. Really old biochar is called inertinite and is found in coal seams where it's been preserved for as long as 300 million years.

There are two main attributes of biochar that have a lot of influence on its performance in soil. One is surface area, and this increases as the temperature of pyrolysis goes up. Pretty intuitive, since what's happening is that all the hydrocarbons are getting cooked out of the microscopic pore structure of the biomass and empty space is what gets left behind. More surface area means greater sponge effects for holding moisture and helping with aeration, and also provides more protected internal space for the soil life to hang out and multiply.

The other important property is referred to as functionality. This is an electrochemical quality that relates to the molecular attachment points on the biochar surface where oxygen and mineral ions are attracted. These in turn help bind nutrients to make them available to microbial and plant life. Functionality is highest in low-termperature biochars because there are still lots of hydrogen and oxygen atoms hanging around. High-temperature biochars will gain functionality after some time in healthy soil or compost.

The ideal biochar for most soil applications would have high surface area and high functionality, but it's sort of an either/or proposition. There are ways to increase the functionality, either by mixing with active compost, or by adding things like clay or metallic oxides (like rust) to the feedstock that form crystalline structures on the surface.

craig howard wrote:
I don't think I've ever been ripped off on alliex.

I have. A vendor shipped me the wrong product and I asked for a refund. I provided mountains of photographic evidence. The vendor denied everything, so I escalated the problem to AliExpress. They initially sided with the vendor but after reviewing all of my documentation agreed that I was due a refund. The problem? I had to return the item. I thought long and hard about this, but being a trusting sort by nature, I went ahead.

That was my mistake. I shipped the unit back to the supplier, and it ended up stuck in customs in Wenzhou. AliExpress said this amounted to nondelivery and denied my refund. An appeal was also shot down. $500 later, all I have to show for the experience is a stack of receipts. I might be able to get my bank to do a chargeback, but I'm not holding my breath.

Never again.

Java:



Turkiye:



Andalusia:




These last two examples probably aren't derived from Muslim influence, but different types of the instrument show up all over Asia.

Hunza (xhigini):



Mongolia:

Not familiar with this instrument, but it looks like another member of the big extended family of two-string "spike fiddles" that you tend to find in all the lands that Persian and Arabic culture influenced over the years. The video reminded me of learning to play the rebab, which is the Javanese version...my first attempts were almost enough to make me want earplugs for myself, not to mention everyone else in the room.

If you need portability and low power consumption, a Raspberry Pi or similar running Linux with e-ink display might do what you want and be very DIY friendly.

Rémy LaCabaneFieutée wrote:
To extend battery life, it’s very practical to cut one or two sections of the trunk, then switch to splitting and stacking the wood. This break between cuts allows the machine to cool down and helps save battery power.

This is a really useful piece of advice...keeping your battery cool will prolong its life considerably, too.