[Stoves] update: coffee-grounds briquettes

[David Young]

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