What is Biochar and How is it Made?

The Science and Sustainability Behind BioBloom’s Premium Flagship Product

Faced with escalating climate challenges and the need for sustainable farming solutions, biochar is rapidly gaining acclaim as a game-changing tool for agriculture, carbon sequestration, and soil health. But what exactly is biochar, and how is it made? Let’s dive into the science behind this remarkable material, and explore why BioBloom’s biochar—crafted from locally sourced, sustainable, native Australian hardwood—stands apart.

What is Biochar?

Soil Amendment, and Carbon Sink

Biochar is a carbon-rich soil amendment produced through pyrolysis—the thermal decomposition of organic biomass in a low-oxygen environment. Unlike conventional burning, pyrolysis traps carbon in a stable form rather than releasing it into the air. The result is a light, porous substance loaded with benefits for your soil. Chemically, it consists mainly of carbon, plus smaller amounts of hydrogen, oxygen, and minerals depending on the feedstock used.

Biochar functions as a soil amendment, enhancing soil structure, nutrient retention, water-holding capacity, and microbial activity. It achieves this through its almost unbelievable molecular structure. Stemming from the beauty and complexity of natures nutrient cycling pathways, and retained due to the highly controlled application of pyrolysis, one gram of biochar contains on average 300 square metres of soil habitat space. It also serves as a highly effective carbon sink, sequestering carbon for thousands of years, making it a vital tool in climate change mitigation.

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Biochar under a microscope.

How is Biochar Made?

The Pyrolysis Process

The production of biochar involves heating organic biomass—in BioBloom’s case, Australian hardwood timber offcuts—in a controlled, oxygen-limited environment.

Let's have a gander at the process:

1. Feedstock Selection: Biochar’s properties are highly dependent on the biomass used as the pyrolysis input. BioBloom exclusively uses sustainably sourced native Australian hardwood offcuts and sawdust, ensuring consistency in quality and sustainability. This hardwood feedstock is rich in lignin, which contributes to our biochar’s industry-leading stability and long-term durability in soils.

   
   

2. Drying the Biomass: Before pyrolysis, the timber is dried to the optimum moisture content. Ideal moisture levels improve energy efficiency and ensure a higher yield of quality biochar.

   
   

3. High-temperature thermal decomposition (Pyrolysis): The dried biomass is subjected to temperatures ranging from 350°C to 700°C in a reactor, under limited oxygen conditions. This prevents combustion and instead separates and drives off volatile organic compounds, leaving behind a solid carbon-rich residue—biochar.

   
   

4. Gas and Bio-Oil Recovery: During pyrolysis, gases and bio-oils are released as byproducts. These we capture, distil and repurpose as wood vinegar and an in-development renewable energy source, further enhancing the sustainability of our process.

   
   

5. Cooling and Screening: Once pyrolysis is complete, the biochar is immediately quench-cooled and screened to achieve our desired particle size. BioBloom’s biochar is finely processed to maximise its surface area and optimise its performance as a soil amendment.

What Makes BioBloom’s Biochar Unique?

1. Sustainable Native Hardwood Feedstock:

   BioBloom’s biochar is made exclusively from sustainably sourced native Australian hardwood timber mill waste, ensuring quality and positive environmental impact. By engaging with sustainable people operating sustainable timber mills we not only reduce waste but also create a premium product tailored to Australian soils.

   
   

2. High Carbon Content:

   Native hardwoods produce biochar with an exceptionally high fixed carbon content, often exceeding 80%. This stability ensures long-lasting benefits in soil and effective carbon sequestration.

   
   

3. Porous Structure:

   The micro-porosity of BioBloom’s biochar creates an enormous surface area—ideal for retaining water, nutrients, and hosting beneficial microbes. This porosity enhances soil aeration and moisture regulation, particularly in the sandy, degraded soils common in Australia.

   
   

4. Tailored for Australian Agriculture:

   BioBloom’s biochar has been well tested in field trials, demonstrating significant improvements in crop yield, water efficiency, and soil health. BioBloom's biochars controlled composition is designed to meet the specific challenges faced by Australian farmers.

The Science Behind Biochar’s Benefits

1. Nutrient Retention:

   Biochar’s ionically charged surfaces adsorb nutrients, preventing leaching and ensuring availability to plants over time. This is particularly beneficial in Australian soils, which are often nutrient-poor.

   
   

2. Water-Holding Capacity:

   Biochar’s porous structure acts like a sponge, holding water in the root zone and reducing irrigation requirements. Field trials have shown water savings of up to 25%, making it an invaluable tool for drought-prone regions.

   
   

3. Soil pH Regulation:

   When derived from hardwoods, biochar can act as a natural pH stabiliser, basing acidic soils commonly found in agricultural settings—removing the need for lime application—as well as, neutralising alkaline soils commonly found in other Aussie soils. I agree, it does seem somewhat impossible to both acidify and alkalise soil depending on the requirement, so how does biochar achieve this incredible magic trick? Again we return to its incredibly complex atomic structure. Biochar's ability to retain 5-6 times its weight in water, simply dilutes the surrounding soil pH towards 7 (the pH of water), hydrating your plants and the microscopic, microbial metropolis developing in, and all over, the particles of Biochar.

   
   

4. Cation Exchange Capacity (CEC):

   This structural complexity also leads to Biochar dramatically increasing your soil’s cation exchange capacity (CEC). But what on Earth is that? CEC is a measure of the soil’s ability to hold and exchange ions like calcium, magnesium, and potassium. This is crucial for nutrient availability and uptake by plants. Biochar’s incredibly high and conductive surface area allows it to bind and adsorb molecules (not absorb, it's different, look it up). This enables access for plants, ensuring they remain in the root zone for longer periods. This property is particularly transformative for sandy soils with low natural fertility.

   
   

   

   Cation Exchange Capacity (CEC) is the measure of a soil’s ability to hold and exchange positively charged ions (cations). Molecules within soil particles carry either positive or negative charges, directly influencing the soil’s capacity to bind and release essential nutrients like calcium, magnesium, potassium, and ammonium. This exchange process is critical for plant growth and nutrient availability.

5. Microbial Habitat:

   The pores of biochar provide a refuge for beneficial soil microbes, enhancing microbial activity and nutrient cycling. This creates a healthier, more productive soil ecosystem.

   
   

6. Carbon Sequestration:

   Biochar locks atmospheric carbon into a stable form, reducing greenhouse gas emissions. For every tonne of biochar applied to soil, an estimated 3–5 tonnes of CO₂-equivalent emissions are sequestered, contributing directly to climate change mitigation.

Hard Facts About Biochar

1. Biochar’s Surface Area:

   One gram of biochar averages a surface area of over 300 square meters, providing ample space for nutrient retention and microbial colonisation.

   
   

2. Longevity in Soil:

   Biochar remains stable in soil for hundreds to thousands of years, making it one of the most effective long-term carbon sequestration methods.

   
   

3. Water Savings:

   Studies show that biochar can reduce irrigation requirements by up to 25% due to its exceptional water-holding capacity.

   
   

4. Australian Innovation:

   Biochar is being actively produced, tested and used across Australia, from sandy soils in the Mallee region to acidic pastures in Gippsland.

   
   

5. Energy Efficiency:

   Pyrolysis itself can be energy-positive, capturing gases and bio-oils for renewable energy while harnessing residual heat to power the reactor.

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Transform Your Soil with BioBloom Biochar

Biochar is more than just a soil amendment; it’s a powerful tool for building resilience in agriculture and combating climate change. BioBloom’s biochar stands out for its premium quality, sustainable sourcing, and proven benefits for Australian soils.

Ready to see the difference biochar can make for your farm or garden? Explore BioBloom’s range of products and take the first step toward healthier soils, higher yields, and a more sustainable future.

Contact us today or visit our website to learn more.

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Here's some light reading for all my fellow soil nerds out there ;). Copy and past the titles into Google Scholar

Sources

1. Lehmann, J., & Joseph, S. (2009). Biochar for Environmental Management: Science and Technology. Earthscan.

2. Australian Government’s Emissions Reduction Fund Guidelines.

3. Field Trials from Victorian Agriculture Department.

4. International Biochar Initiative: Biochar Benefits.

5. "Water Retention in Sandy Soils Amended with Biochar," Springer Science.

6. "Biochar and Carbon Sequestration," Journal of Environmental Quality.

7. Nuffield Scholar Report: Biochar’s Role in Australian Agriculture.

8. FEECO International: Biochar Production and Applications.