No electricity at the market, so airpot is my only option.
For two years before I got electricity, I found
this and a sturdy camp stove sufficient. Well, I did have the large (1.5 gal) thermal pot you see in the picture John posted, which cached the water once it boiled. Kept it around 195, +/- 5.
For two more years I cached the water like this. I may be doing something different this year.
Let's put it this way -- I can't imagine any on-site method you might contrive that could possibly be worse than making the coffee at home and serving it over time.
On the other hand, if you dash quickly to the market, set up really fast and start selling, it might all sell out well within what I consider an in-contact-with-stainless-steel maximum -- one hour.
When is peak attendance time at the market? How many customers show up each week? What is your beverage competition at the market, or nearby? Is there a place where people can sit and hang out, or will they invariably be taking their coffee back to their car with them? How close is the parking lot (which bears on the question of whether folks will stare at a coffee stand with their hands full, shrug, and trudge off to their car and return, or not). What's the climate like where you are? Rainy? Cool?
Advice: don't let lack of electricity keep you from brewing coffee fresh at the market. You're a man. You have mastodon hunting in your genes. You can handle heating some water.
The issue of grinding: I have been able to have my van adjacent to our canopy, so those same two years of heating water via propane involved grinding coffee using an inverter. Use a faithfull
Kill-A-Watt to check your grinder's load, then
exceed that by 100% or more.
I still roast from the vehicle battery. If your vehicle can't be near your booth, I'll grant you have an issue.
I'm not sure what the lifespan of airpots is but I think I remember Nimbus saying once that he times his out at 45 min.
That's a good number. My use of an hour leaves 15 minutes to punish latecomers to events where I'm serving.
