Coffee can be ground without batteries, hammers, or...

Putchaself in a nice third world country where the water is boilt (Br.) over
an ancient Primus 00 Kerosene stove.  Plenty of solar power there but no
converters.  Now with coffee in hand place suitable amount into a hand
ground coffee mill such as is used in Turkey (RThanksgivingC)  Grind away.
One grinderfull makes a fine presse' or drip.  Grind it fine and you don't
even have to brew it.  Just put a pinch between cheek and gum...

Al Z Heimer