Well, this is my secret as far as I know. It weaned my off Tim Horton's, and saved me a little cash.
Cold coffee, IMO, is pretty good but it is hard to beat a Timmy's. This coffee helped to slow me down a lot on the Timmy's.
What you need.
Coffee. Any brand will do. I have tried the good and the cheap - they both come out about the same. I think the difference is the tastes comes out with the acids in the hot brew. Since this is a cold brew they are about the same. Both are good and no (less) acids.
A bottle of cold water.
Three large plastic take-out cups.
A 6" diameter round piece of cardboard.
Step 1: Equipment
Three large plastic take out cups. I hate to throw anything away. You can likely tell by the curtains in some of the shots. Bigger the better as far as I am concerned. With these cups I can drink for about a day. I drink a lot of coffee when I am off work though. (And at work.)
I will get to the cardboard later.
Get yourself a 5/64" drill bit from the tool box, and wipe the oil and grease off it. Using your fingers to twist the bit drill a dozen of so holes in the bottom of one of the cups. ( Only one cup.) I don't really think that the placement matters as long as they are in the bottom bottom. ( Not the side bottom)
Clean away any little pieces of plastic that may be around the holes. You should be able to see cleanly through the holes with out seeing any little plastic hairs.
Place that cup inside one of the other cups.
We are now ready to start making coffee.
Step 2: Night Before.
The night before you want a coffee (if you are starting new.) you take the two stacked cups and fill the inside cup to the hump in the cup. See photo to see the hump.
Fill the cup with cold water and mix-up the coffee grounds with the plastic spoon you also received at the take out window. The grounds will float for the start of the process. once well mixed and all the grounds are wet put the lid to the cup on and place in the fridge. Wash your spoon and wipe the counter.
After about an hour take the cups out of the fridge and stir the grounds again. They should sink by this time as they will be soaked with water. Add some more water if you think it will take it. Make sure the level does not rise over the level of the lip of the outer cup, or it will spill. Put the lid back on and return to the fridge for the night.
Step 3: The Brew.
The coffee grounds have been soaking for about 12 hours and can be brewed now.
Take your third cup and place it (Bottom down) on the center of the 6" diameter circle of cardboard. Take a pencil and draw the outline of the bottom. Your should have a circle the size of the bottom of the cup centered on the disc of cardboard. Cut out that center circle.
Test fit the bottom of the empty cup into the inner circle. You may have to trim it but the cup should slide in about 2" at least, but not too far.
Test fit it with the top of the cup. It should side on the rim of the empty cup with any obvious problem.
Now the brew.
Get your double cups with the grounds out of the fridge and remove the lid. Give it a last stir.
With one hand lift the inner cup from the outer cup, but always have the inner over the outer so the liquid that comes out falls into the outer. lift it high enough to quickly slide the cardboard between the two cups and insert the upper cup into the hole of the cardboard.
Rest the cardboard on the lip of the lower cup and let sit. I should take about 15 minutes for the upper cup to stop dripping.
Once the upper cup has stopped dripping remove it from the cardboard and place it inside the third cup you have had hanging around. Fill the cup with water again and replace the lid and return to the fridge for a second soak. ( this batch will be ready after work - a little weaker.)
Set aside the cardboard for later. You will get a lot of use from this.
Now you have about half to three quarters of a cup of black gold. A very high concentrate coffee.
Step 4: The Pour
Pour and enjoy.
What I live about this style of coffee is I can make the glass as strong as I like. I even stopped adding sugar to my coffee- that is how much I like this. I was a3 and 3 guy for a long time.
I put anywhere from 1-2oz. on a glass and top it off with cold milk. mmmmmmmm Good.
Some people like to add boiling water, then the cream and sugar to taste.
Pour what you don't drink into an old water bottle and either put it in the fridge or take it to work if you have a day job. Remember you have more on the make in the fridge.
After you have drained the grounds after work start the process all over again. You will always have a fresh brew with minimal fridge space being used.
Notes on this:
Any little grounds that get through the holes in the cup will settle to the bottom quickly. You will see as you get to the bottom of the cup that they are stuck it the bottom. As long as you don't give a rapid shake to the cup they will stay there. You may lose about 1/2oz. per cup make due to this.
Hope you enjoy it.