This reminds me of a couple of NCO's and the way they did their coffee in the field.
On a pot bellied stove, they place a 2 QT coffee can. Then inside they poured the beans and water. Let them boil and stirring every once in a while.
Pour out what they wanted to drink.
Add a few more coffee beans.
Fill up with water.
Repeat process.
This would go on for about a week before they would start fresh with a new can. I think around every 2-3 days, they would dump out the contents and sort of wash the can.
Seemed to work for them.
On a pot bellied stove, they place a 2 QT coffee can. Then inside they poured the beans and water. Let them boil and stirring every once in a while.
Pour out what they wanted to drink.
Add a few more coffee beans.
Fill up with water.
Repeat process.
This would go on for about a week before they would start fresh with a new can. I think around every 2-3 days, they would dump out the contents and sort of wash the can.
Seemed to work for them.