Step 6: Test the battery
The final step is to test it out. We need a multimeter to test the battery accurately, but if you want to check it works without a multimeter, just put the two wires on your tongue. If you feel a slight tingle that tastes metallic it works!
If you want to be precise, measure the voltage and current with your multimeter.
My battery produces between 0.8 and 1.1 volts at around 2-5mA. Using a joule thief you could run an LED from this. A larger surface area and stronger electrolyte concentration would improve the battery, but that is up to you to try...