When you setup a worm bin or worm farm, decomposition takes place in three stages for the most active microorganisms.
Phsychrophilic bacteria begins to process at temperatures below 70 degrees Fahrenheit
Mesophilic bacteria, the fastest decomposers process between 70 to 100 degrees Fahrenheit
Thermophilic bacteria come into play at temperatures above 100 degrees Fahrenheit
When managing decomposition, pay attention to the carbon (newspaper, cardboard…) to nitrogen (vegetable scraps, grass clippings…) ratio as well as moisture and oxygen.
Composting with worms is a more controlled method of basic composting as well as speeds up the process. You maintain a constant temperature which enables the most active bacteria, Mesophilic to take over. Worms move through the organic matter helping to aerate the decaying matter as well as making smaller particles of the decaying matter, hence leaving more surface area for beneficial microbes to work on.
If the moisture content gets to high, usually above 80%, the decaying matter becomes compacted, the same way the landfill does. This is when the worm bin can begin to change over to those nasty anaerobic organisms which can be harmful to your worms and even begin killing them off.
Once the moisture content begins to rise even more, the decaying matter releases a liquid called leachate. You will see many websites refer to this as worm tea, which it is not!
Worm tea is derived by brewing worm castings which are full of aerobic microorganisms. This process is done by aerating the worm castings, warm water and unsulphured molasses for approximately 24-48 hours in order to explode the aerobic microbe population.
Leachate is usually the opposite, full of anaerobic organisms.
If you are getting a little leachate from your worm farm or worm bin, try adding several inches of dry shredded newspaper on top and place the lid on it. This will absorb a little of the moisture. If you are getting a lot of leachate, it might be time to remake the bedding for your friends!
Now that you understand the process you can probably write to all those german websites that are trying to convence you that Leachate is actually worm tea.