The hard thing about proving compost tea is that there are so many recipes and most people at universities don't know how to make it, or even what part is important. They get to do their research when a corporation sponsors it mostly. Look at the uproar when grad student Daniel Donato published in Science that forests recover more quickly when the fallen timber is not harvested. The president of the OSU told the magazine not to print the article! It was highly shameful. No corporation is going to sponsor a study of compost tea because if it works, it tells the people not to buy their product. Who wants to sponsor that?

In addition, some studies are poorly designed. The study last year that was supposed to show that conventional produce is as good as organic went from wwII to present. Well, most produce was organic until the last couple of decades, so for most of the study, they were comparing organic to organic. No wonder they found very little difference.

There are published, peer reviewed studies that show the efficacy of compost tea. However, until there are uniform standards, it will be hard to figure out what works and what doesn't. I was making fungal compost tea wrong for a year or two and wondered why it didn't work. Elaine Ingham told me how to fix it and now it works great. Making compost tea is a little bit like making a fantastic meal. Nobody makes a scientific proof that a delicious meal can be made, they just try to make it, and many fail unless they do it very carefully.
John S
PDX OR