The Weird and Wonderful World of Compost Brewing
                                    (4 June 2015)

Compost brews inject biology into the soil, encouraging and activating the soil life within. The distinct advantage to utilising compost brews as opposed to artificial fertilisers is that they make plants actively source out beneficial bacteria and soil life, forming mutually beneficial relationships.
 

As with other fertilisers and soil improvers, there are different brew mixes for different applications, such as those predominately bacterial or fungal in nature, or a balanced mixture of both. You can make your own compost brew extracts and foods or purchase pre-made ones with all the math, science and research taken care of for you.
 

Once applied, a compost brew remains in the soil for up to 3 months, being effected by factors such as soil type and the relative quantities of organic matter and humus in the soil.  
 

Some Tips & Tricks:

• Non-aerated brews and teas differ from aerated ones as they add nutrition to soils but do not inject active biology into them.
• Rainwater is the preferred option for use in compost brews wherever possible; otherwise, ensure treated water is aerated for 24hrs beforehand to dissipate chlorine. 
• Can’t overdo strength of compost brew but you can, however, underdo.
• Time of year and temperature effects brewing times – avoid extremes wherever possible. Hot weather brewing time is 24hours maximum, and cold weather brewing is 36 hours maximum.

• Apply made up brew within 2 hours of ceasing aeration and preferably in low light situations (early morning, late evening, or overcast weather desirable).

• Clean brewer after every use to remove scum buildup.

• When using molasses in compost brewing, ensure it is the unsulphured variety known as blackstrap (sulphur eats beneficial bacteria).

• Seasol can be used but the kelp is not produced in Australia, making it less sustainable – there is a quality Australian product available which is also double the strength www.australiansoilbiologicalsupplies.com.au.   

• If using Charlie Carp for brews, make sure you purchase the organic version.

DIY Compost Brewers:

• Any sturdy container can be converted into a compost brewer with the limiting factor being the capacity of the high pressure air pump accompanying it. A push top bin is ideal. 

• Use 15mm high pressure plumbing pipe and 19mm clear tubing to assemble the pump componentry of your brewer – tip: check compatibility of fittings whilst in store.

• You will need a 250 micron bag to hold the compost extract. Alternatively, old stocking also works well.

Making Compost Brews:

• Add liquid brew ingredients to brewer with appropriate amount of aerated water to incorporate;

• Put compost extract in bag or stocking and massage vigorously for 30 seconds to one minute before suspending in centre of unit; doing so ensures you get enough air through the extract and also prevents particles from settling in the bottom of brewer;

• Brew for appropriate time taking into account time of year etc.;

• During the brewing process, assess levels of bacteria under a microscope and rectify if needed. 

For more information on soil health, compost brews, courses and products:

www.soilbydesign.com.au

www.australianbiologicalsupplies.com.au

 

An open-air composting system in the making.

Tools of the trade.