[InfiniteNow]

Originally Posted by maikeru

As other Hypographers might know, I'm a coffee addict. I drink a couple espressos a day, and this leads to a lot of spent coffee grounds. Usually I get a bag or two of them per week. Most of them have been going into my house plants or outside to feed the fruit trees, but I notice they can take a while to decompose. I also use them in potting soil mixes. I was wondering if I could do something more constructive and helpful with them...like making them into charcoal. Coffee grounds are already halfway there--they just need more roasting. Without burning my house down or making my neighbors call the police or fire department on me, are there any safe and relatively easy ways I could convert my coffee grounds into a small amount of charcoal? I can also get additional coffee grounds from my local Starbucks. I've been doing that recently for my gardening outside.

If I don't reply to this for a while, I apologize. Will be on vacation for a few weeks. I'll read and answer as soon as I get back.

Guys,

While I, too, enjoy a kick ass cup of coffee and really love espresso, your hyper caffeinated banter is distracting from a serious response to maikaru's question. It's a question to which I'd also like an answer, since it's one that I've not yet encountered in the terra preta threads, and I find it incredibly interesting.

[DFINITLYDISTRUBD]

Infinitenow-It's a question to which I'd also like an answer,

[See below]

Moontanman-Hey, you could grow earth worms with the grounds, even rolly pollies. Great fish food, fish bait, or earth worm castings for plant fertilizer.

And

-D.d.-I've been bagging them for mixing in to feed tastey goodies soon to be planted.(

And

Freezy-Have you considered charring the grounds DD?

And

-D.d.-Put 'em on foil and let em hang out in your broiler or put em on a microwave safe whatever and nuke em to char.

Microwaves do an excelent job of charring things and require less time and energy than an oven to do it...And using your broiler instead of trying to bake the grounds yields results faster. Of course there are solar alternatives.

maikeru- I was wondering if I could do something more constructive and helpful with them.

Mixing them into your soil is very useful and constructive
especially if your's is anything like mine. It needs all of the softening up I can give it and grounds definitly fit the bill as a soil additive for the job as they fill the clay and prevent it from turning back to a concrete like substance.

[DFINITLYDISTRUBD]

I really don't understand how charring things HELPS the environment...Charring things CREATES Co2 and destroys otherwise useful nutrients...is it really any better than composting? (both produce waste Co2 AFAICT)

BTW Infinite The post above was just to show you we were sneaking a few helpful tidbits in there But yeah we were getting just a little unruly

[InfiniteNow]

No worries. Thanks for the helpful synopsis.

[freeztar]

Originally Posted by DFINITLYDISTRUBD

I really don't understand how charring things HELPS the environment...Charring things CREATES Co2 and destroys otherwise useful nutrients...is it really any better than composting? (both produce waste Co2 AFAICT)

When something decomposes, the carbon is recycled back into the environment. With char, the carbon is locked in and stays in the soil for thousands of years, effectively taking it out of the carbon cycle. This reduces the amount of carbon available for CO2 production.

[maikeru]

Originally Posted by Moontanman

Hey, you could grow earth worms with the grounds, even rolly pollies. Great fish food, fish bait, or earth worm castings for plant fertilizer.

IIRC, spent coffee grounds are toxic to earthworms because of the caffeine and other related methylxanthines. Caffeine and its cousins (theobromine, theophylline, paraxanthine, etc.) do a pretty good job killing or paralyzing many invertebrates and pesky herbivores (basically, caffeine is a natural insecticide). They don't have it good like humans do, who are highly resistant to (and benefit from) the effects of the stimulants. I think it takes a little while of aging, decomposition, or leeching to make them palatable to earthworms. Fungi seem indifferent to the caffeine. BTW, I might try raising some earthworms for my terra preta later on or add them to my terra preta pots and let them do their thing.

Dfinitly, it's an arctic fox kit (puppy) in my avatar. I used to read an online comic that featured an arctic fox as one of the characters, and took a liking to them. They are cute. It also appeals to the nature lover in me.

I'll try and experiment with the microwave option and report back here. One reason why I am interested to char my grounds is that they're already of a good particle size and it saves me the need to always buy or create my own crushed charcoal from wood charcoal. Coffee grounds also have high surface area, oils, proteins, carbs, minerals, and other good stuff in them which might make for a nice terra preta. Anyway, you can see why I think they are a good carbon source for pyrolysis (charring). Who knows how many tons of spent coffee grounds go into landfills when they could become charcoal or terra preta and benefit the world instead.

Dfinitly, while I won't go into a detailed discussion of the characteristics of charcoal and terra preta, locking up carbon in a permanent or long-term form makes for a great soil amendment, possibly one of the best nature and man ever devised. It benefits the soil, almost any soil, in numerous ways. Reading a few of the threads in the forum, including the parent thread where it all began, might shed some light on your questions. Also, right now the world is in a situation where we, due to our activities, are releasing excess carbon beyond what natural systems can handle, and this may be driving global warming or climate change. Taking some of that excess out of the system and slowing the increase in CO2 production, restoring depleted or destroyed soils, and boosting food production or plant products for renewable biofuels are some possible benefits from terra preta. We have created many problems for this world and ourselves, and it would help if we could set some of them aright.

Now that I'm back from my vacation, I discovered the fig tree and banana tree I put in the terra preta have flourished exceedingly well. Within another week or two, they should almost double in size from when I repotted them. (But I have been feeding them a lot of natural fertilizers like leftover milk, egg shells, and coffee grounds, so this might be expected.)

[greenkira]

Well, this is a speculative post since I don't really have the means for my own terra preta experiments right now, but here's some ideas.

You could probably just put the grounds on a cookie sheet and roast them in the oven until they get crispy. Roasted beans are pretty close to being charred to start with. Drying the grounds on a cookie sheet before trying to char them would be a good idea anyway.

You could put them in a tin can and put it in a bonfire, in the coals when you barbecue, or possibly in one of those little biomass gassifier stoves. Aren't some of those basically one can inside another can?

But what I think might do the closest to real terra preta would be to get some oven bake red clay, that cooks around 350 F, and mix the dried grounds with the clay so that you've got as little clay holding the grounds together as possible, make a bunch of little beads or tabs, and cook those up. Doesn't have to be in an oven, you could build a fire around them and just make sure they get some good time in the coals (an hour at least). Then you've got mixed biochar and porous pottery.

Once you've got that, you could treat it with just about anything liquid - compost tea, urine, fertilizer, or mycorrhizal inoculation like MycoGrow. I saw some pictures of chunk charcoal that had been thoroughly colonized by mycillia, soil fungi that help root growth, so it makes sense to me to give it a good start like that.

Hmm, one more idea based off of a video I saw on greenpowerscience - you could also put grounds, loosely - maybe with some scrunched up paper to provide air pockets- into a clear glass jar and hit it with a fresnel lens. Those things look like so much fun! The jar might explode though and you can burn yourself fairly badly with one of those lenses, but hey...

[freeztar]

Originally Posted by greenkira

Hmm, one more idea based off of a video I saw on greenpowerscience - you could also put grounds, loosely - maybe with some scrunched up paper to provide air pockets- into a clear glass jar and hit it with a fresnel lens. Those things look like so much fun! The jar might explode though and you can burn yourself fairly badly with one of those lenses, but hey...

Just a quick aside...
You might enjoy this thread, Kira, where Greenpowerscience was a participant. Several of us are trying to figure out how to make char with solar power.

http://hypography.com/forums/science...olar+parabolic

[maikeru]

I tried the microwave and oven ideas.

Microwave doesn't seem to work so well, at least on the 5-, 10-, and 15-minute lengths I was using. I was wary of leaving grounds in the microwave for longer periods than those, in case they caught fire. I have had things catch fire in the microwave before, and that's the last thing I want.

The oven does work but it takes quite a while. I experimented with my oven set at 400 degrees F (for a low-temp char), using a clear glass casserole dish, and dry grounds. I noticed that grounds started to char after about 20-30 minutes, and I ended the experiment there, once I was sure it was effective. However, I'm not sure it's worth the energy used, and with the weather so hot (between 30-40 C depending on the day), I don't want to make the house any hotter than it already is. I'm going through the hottest and worst part of summer right now in the desert, and I'm dying...

In my case, charring the grounds might not be practical right now. I think I might use them for vermicomposting and to continue to make new soil and potting mixes.

[palmtreepathos]

Hmm... it may just be me but I had gotten the idea that coffee grounds already were charred, especially the dark roasted ones used for espresso. I am using them as char in my compost and garden. I treat them to a soak in natural fertilizer and then mix in the soil with some sand as my soil is pretty heavy clay.

I also mix them with old grass clods (chopped up) with the soil from their roots to a rotary composter, some leaves or wood chips adds larger bits of organic matter. As part of the soil amendments I add liquid molasses, ceramic powder and ground granite dust. I am now growing an avocado in this mix and for the first time would call the thing a "tree"... lol

Garden Grounds - Home

Grow Joe--Plants benefit from neutralized coffee grounds