Compost tea is a process of not only extracting microbes, but “waking them up” and growing them to the point where some of them are reproducing rapidly.  Many machines have inadequate aeration systems, which may not keep dissolved oxygen levels in the optimum range.  The microbes in compost require little air when dormant, but when actively growing and reproducing require a lot of oxygen.  Good compost tea must maintain dissolved oxygen levels above 5.5 ppm during the entire brewing cycle to ensure that only the beneficial species are being encouraged.  It is a simple fact of nature that almost all of the beneficial organisms require an aerobic environment, and almost all pathogenic species prefer anaerobic conditions.  By maintaining a highly aerobic environment during the tea brewing process, one can be assured that a beneficial tea is being made.  This factor is even more important when brewing compost tea at higher altitudes and warmer temperatures, where is it more difficult to maintain higher oxygen levels.


The GEOTEA machine excels in aeration because it utilizes a high output air pump in a relatively shallow (30”) tank with a lot of surface area.  Beyond that, the GEOTEA machine incorporates “wave-form technology” on the water surface which mimics the wave action in whitewater rapids.  This organized movement of water entrains oxygen at the surface, much like the whitewater effect in a river or waves on a beach.  Most other machines bubble air through the water with airstones or membrane diffusers which can restrict airflow and clog with biofilm over time.  The GEOTEA machine uses a custom-made stainless steel air diffuser tube which doesn’t ever wear out, restrict airflow or clog with biofilm.