Brewing Compost Tea - Why the need for a bag?

Hello

I have been looking about and I cant seem to find any credible article on why you need to place your compost in a bag within the brewer.

However, I have read a few things that talk about mesh size being too small.

I am curious as to why it cant simply free float in the water as its brewing then be strained out at the end.

If anyone has a credible answer that would be lovely.

No reason why not.

Except...
...if you are using a bucket with a spout, then the spout will get clogged by the debris. That's the only experience I've had that I could have used a bag.

Nowadays I'm anti-bag as it just adds more environmental pressure. I just put the compost/manure in the bucket with water, and strain out a little bit at a time as I need it.

It works quite well to have it free floating, It really just depends on the brewer design. Some larger designs may not be able to supply enough oxygen through only one source. In that case another air supply is added somewhere else to improve oxygen levels. When this is done it just makes sense to add a source of microbes right near the soirce of oxygen. If you have a big clump of microbe fuel then the bag just keeps it right where the multiplying microbes can jump off and into the oxygenated water. Otherwise you risk perfectly good microbe potential going to waste in a less oxygenated area .

So mainly i have seen the bag method used as a supplement in larger brewers.

I have brewed in a 5 gallon with one good pump and see no need for a bag since by design the fluid is fully circulating every little bit. You really don't even need to strain it at the end unless you are using a sprayer or watering can with small holes.

Free floating compost could result in different strains of microbes dominating. Straining the slurry at the end may also remove many microbes and in particular fungi attached to the compost. Only one way to know, compare the two with a microscope or try both methods and do a field trial.

Are you using a water circulating pump? Will it get jammed up with particulate matter trying to flow through it? If yes then bag, if no then bag optional.

I have a 5 gallon bucket and an air pump. I will be using a 1/2 inch pvc pipe going down the middle to the bottom. Getting pluged up isnt an issue.

I have a 50 gallon home made system with an airlift powered by an air pump. I do the free floating compost out of simplicity, and like it better this way.

I also haven't been removing chunky stuff from the compost and this has led to a couple issues:


- big debris clogging the airlift
- spigot at the bottom of the barrel getting clogged a bit


This is generally not a problem if you have a simple system that you can baby sit. I can see having a bag being useful if you are making compost tea on a larger scale, maybe?

Tim from microbeorganics.com uses custom made diffusers and places one into the bag.

I don't use diffusers and like to keep it simple that way. Results under the microscope have been ok so far.

I use an Eco 7 commercial air pump that outputs 200 liters per minute. Tim uses a 150 liters per minute pump for his 50 gallon systems so I got a bit of extra room not using diffusers.


I think someone in the thread mentioned using a water pump. That might be risky with some of your microbes.

If you're planning on applying your compost tea foliarly, then the debris from the compost can easily clog your spray applicator. Other than that, I don't believe a bag is actually required.

I use 55 gal. barrels for compost/manure tea brewing I do not use bags to keep the solids separate I do, however, use a piece of muslin when syphoning the tea out of the barrels, the barrel end of the syphon hose has a piece of muslin clamped over it so no chunks get into the primer pump I use to get the syphon started.

I think the whole idea of making "tea bags" came from people thinking it was a bad idea to brew "cowboy" style for some reason.

I also stir my solids with a long wooden paddle I made, and I use the same batch of solids over and over, just adding a bit of new before I top off the barrels.
Then I cover them and let everything settle to the bottom, this way I can get nice "clean" tea for the plants.

Too much material will settle on the bottom of the bucket and create an anaerobic zone. Use a bag to avoid this from happening.

Joe

I don't mean to this to sound b*tchy, but running pumps all the time doesn't seem especially sustainable.

For example, the 200l/m pump by Eco7 uses 280w ( listed on Amazon), which would mean around 48kg of carbon released each year per pump assuming mixed source electricity.

If the compost tea leads to a boost in productivity which in turn leads to at least 49g of additional carbon capture I get the value of it - i.e. 49kg of additional carbon storage over and above making compost tea without the airpump, and just giving it a stir every day - but I'm not fully sure that that works out.

Have you guys running the large compost tea setups looked at cost vs benefit?

I'm asking purely because I'd be interested in seeing the results of it.

I don't use air pumps, my barrels are set up to be stirred twice a day, the paddle seems to do enough aeration.
The paddle I made for this has several blades on a single vertical, these are angled so the liquid moves up from the bottom of the barrels with the stirring action.
When I pump tea from a barrel it is done with a hand pump, no electricity needed.

I use the tea on a rotational schedule so every week there are beds getting tea and beds getting only water ( use a water collection system for the gardens and orchard water ).
My teas contain; compost, minerals from out of date multi-mineral tabs and ground oyster shells, green sand and rock powders, manure and worm castings, with the bulk of the materials being compost and manure (also composted).
Most of the carbon in the left over plant material is then recycled through either the worm bins or in the hot compost heaps, these are then either used as straight soil amendment or made into tea for water born fertilization.

My cost is nil, since everything is made onsite and simply part of the recycling of nutrients.
The benefits are; healthier plants and larger harvest of produce and fruit.
As our systems grow, we will be creating more income through the sales of produce.

We have chickens on a deep litter system using straw as the floor medium along with some leaf material. This straw ends up well mixed with manure and we put that into a hot compost heap which reduces dangers of contamination through plant uptake of pathogens.
We have not moved into humanure systems as traditionally thought of, our septic system uses bacteria in a multi stage tank and flows out through a mycorrhizal-remediation leaching bed which tests results show is clean, non-contaminated out flow.