In the early 90s, we were staying on a boat, and the host served excellent coffee with breakfast. I saw her pour this syrup into a cup and add boiling water to make it. I had to know.
She sent us to "toddy coffee" at
http://www.toddycafe.com/shop/product.php?productId=67 (well, then it was a phone call).
Basically, you put cheap coffee and water in a container for 12 hours, then pull the plug at the bottom and let the liquid drain through a 1/2" thick filter. They say 16 oz of coffee and fill with water -- we find that 13 oz (as it comes from Walmart) works fine.
You end up with a concentrate. You mix it with 3 or 4 parts boiling water when it is time to serve. The syrup keeps for a few weeks in the fridge (unless the fridge belongs to th).
We've been doing it ever since.
Basically, you end up with coffee much lower in acids due to the process, instead of having to buy premium coffees to get the same thing. (The taste doesn't get noticably better with premium coffee, either.)
Also, a good part of the caffeine is lost in the process. Not decaf, but probably like a 50-50 mix of decaf and regular. But read the linked page for details. Also at
http://www.toddycafe.com/cbinfo/secret.php
The taste and price are great -- but also, you just use what you need, and prepare cups the way you would prepare instant. So you never make too much or too little.
Your coffee may vary, but about 1 in 3 guests who stayed with us wound up buying one of these over the past 10 years.
CheapCoffee36