[Stoves] update: coffee-grounds briquettes

Crispin Pemberton-Pigott crispinpigott at outlook.com
Tue Aug 26 17:31:05 CDT 2014


Dear David

Thanks for the update. Do the pucks feel really dense even when dried?

Thanks
Crispin


I've succeeded at producing some briquettes from used coffee grounds
and pulped newspaper.  I haven't found a great way to burn them without
a burnt-coffee odor or clouds of smoke, but I think that the key is to
crumble them slightly to expose more surface area to heat and oxygen.

I have a hand press, called an Aeropress, for making a cup of espresso.
It's a polycarbonate cylinder with a perforated plastic cap at one end.
You put a paper filter in the perforated cap, put your coffee grounds
on top, pour hot water onto the grounds and stir.  Then you press a
polycarbonate plunger through to press coffee into a glass through the
cap.  A rubbery black plastic plug at the end of the plunger forms a
watertight, semi-airtight seal.  After you've pressed your coffee, you
remove the plastic cap from the cylinder and push the plunger the rest
of the way through to eject a puck of damp coffee grounds.

The damp pucks are crumbly, and once they dry out in the sun, they fall
apart easily.

Based on a suggestion on the list, I mixed equal parts (by volume) of
soggy pulped newspaper and sun-dried used coffee grounds in the hope
that the cellulose would hold a briquette together once formed and
dried.

Now, how to form a briquette?  Using the Aeropress with a paper filter,
as if I was brewing coffee, I squeezed much of the water from the
pulp/grounds mixture, and then I ejected the puck onto a sheet of
newspaper, where I let it dry in the sun.

I have burned the briquettes whole in a campfire, in a rocket stove I
built, and in my TLUD.  Burning them whole produces a lot of smoke.
Burning some fragments of a briquette in a mix of biomass (mainly dry
twigs cut into chunks) worked pretty well, and I will have to try that
again, soon.

I will make some pictures of the briquettes and send them a little
later.

Dave

--
David Young
dyoung at pobox.com    Urbana, IL    (217) 721-9981

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