This is a solar alembic, or pot still, made from square foot mirrors, which can produce between 2 and 5 ounces of distillate on a lazy sunny afternoon.
Please note: it is illegal to distill ethanol except for fuel, and you must have a federal permit to do so. However they are not that hard to get, and our government is actually encouraging the citizenry to experiment with this which is why I'm writing. I am with a group who have one.
Here is the link for a permit, which you MUST have. You need to specify that you will be making alcohol for fuel on the permit application.
You need 3 square foot mirrors, about $7 at your hardware store to build the reflectors..
Cut a 1 inch hole in the middle of your jar lid to allow the beer bottle to poke through.