Re: [compost_tea] The points to use to decide on which brewer

From: <soilfoodweb_at_aol.com>
Date: Sat, 15 Nov 2003 15:34:46 EST

When buying a brewer, there are a few steps you want to think through.

First, figure out the amount of tea you need to put out at any one time.

If you can put out 5 gal today, and 5 tomorrow, and 5 the day after, why buy
a machine that makes 50 gal? If you own 10,000 acres, ok, you need a big
machine. If you own an acre or less, a 5 gal machine will likely do fine.

Second step, who sells machines in your size? Narrow your choices down just
based on that.

Third step, compare the different brewers.

If you are going for the 5 gal size range, you are looking at KIS brewers,
Alaska Giant, and Bitti-Brewers. Their websites show good numbers from SFI, so
they all are capable of giving good results.

Fourth step, ask the compost-tea list serve for comments on each brewer you
are looking at. Here's a summary of what I have read.

The Alaska Giant has been shown to require that the soaker hose has to be
changed every other brew. There have been questions about the petroleum-base to
the materials the soaker is made of. That is a concern.

The KIS brewer has had nothing negative said about it, that I know of, and
lots of positive.

The Bitti-brewer results have been variable, but I think that's because Bob
tells the people brewing with his machine to put an extra air wand outside the
compost container, as well as the wand inside the compost container. Bob
doesn't do that himself, I think. So, Bob's numbers weren't as good as the
numbers that other people got. That one had me shaking my head, until Kevin pointed
out the situation. I think Bob is starting to test his machines using the
two-wand aeration, so Bob's numbers should start improving. The confusion here
will be less, I hope.

So, from my point of view, that would bring you to making a decision between
the Bitti and the KIS. Take a look at both. More parts to lose on the Bitti,
the air pump on the KIS is cheaper. It won't last forever.

So, make your decision based on these kinds of things.

------------------------------------

If you are going for the bigger machines, pay attention to the kind of pump
on the machine. Did the manufacturer check to see if his pump kills
organisms? Where are his data? Don't accept "trust me". There's a machine on the
market that we demonstrated to the manufacturer that his pump to take the tea
from the brewer into a holding tank was reducing numbers of fungi and bacteria by
50%. Keep that in mind, when buying something. How are you getting large
volumes OUT of the tank?

Ease in cleaning is important. Can you get to the bottom of the tank? Are
there square corners in the pipes, knowing that in a month or so, that corner
will be bio-film filled. It isn't right away that the problem develops. With
the commercial Microb-Brewer, altered from the original design we tested at
OSU, the pipes and pumps were changed to make the machine look prettier. The
numbers on the changed machine were similar to the original, not-pretty design
for the first couple of runs, but then, look out, the numbers dropped terribly
as the bio-film developed. The manufacturer claimed that our methods had gone
awry, that we didn't know what we were doing, because the numbers were coming
out lower. It wasn't us, it was bio-film. But the manufacturer got mad at
me. Stopped speaking to me all together. Called me all sorts of bad things.

SFI just tests the tea, we don't have to know why the numbers are coming out
poorly. Usually I try to figure it out, and with the Microb-Brewer, we did
figure it out. But not until after the damage was done. The Microb-Brewer is
no longer for sale in the US.

Next thing to check -
Are there surfaces in the machine you can't see, can't get to to clean?
Those places build-up biofilm. There's a brewer on the market that has discs in
it, and you can't see, and you can't reach, the bottom sides of the discs. It
is not fun getting the discs out to clean their bottomsides. Think about the
time involved in cleaning. Most LARGE brewers should have a way to rinse the
tank down as you pump the tea out. Talk to Bruce Elliott on this one. He
developed the solution for this.

The compost container has to allow free movement of the compost. Solid
baskets that don't allow compost movement, that allow the compost to compact in the
bottom, are going to cause you fits. Compost should be in bags, so easy-flow
is possible. The EPM baskets are there to keep the bag of compost from
twisting in the water flow, so the compost isn't constricted in that bag-basket
design. But any other brewer with a basket has to have an aerator inside the
basket, or the compost compacts, and goes anaerobic (happens at about 10 hours
into the brew, so beware of the brewer that only has data for hours 0, 8, and 24)

Bubble sizes should be medium to large, not micro-sized. Tiny, tiny bubbles
are a bad idea. They shatter the fungal hyphae. Ask for the data showing
good FUNGAL results. And please make sure the lab they are testing with uses
decent methods.

No data? Don't buy the machine.

Only plate count data? Don't the machine. They are trying to pull a
fast-one on you. Ask them what plate count data mean. Typically, you'll get BS
coming back at you. They have nothing to document any relationship between plant
growth and plate counts.

Anyone else have any other points that they use to determine which machine to
buy?

Elaine Ingham
President, Soil Foodweb Inc, Oregon
Soil Foodweb Inc., Australia
Soil Foodweb Inc., New York
Soil Foodweb Inc., New Zealand
Soil Foodweb Inc., The Netherlands
Soil Foodweb, Inc., Mexico
Board Member, Sustainable Studies Institute, Eugene, OR




Received on Sat Nov 15 2003 - 16:34:09 EST

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