What is biochar? A UK-focused explainer

What is biochar? it is a carbon-rich, charcoal-like material produced by heating organic biomass—such as wood, crop residues, or agricultural by-products—in a low-oxygen environment. This process, known as pyrolysis, creates a highly stable form of carbon with unique physical and chemical properties.

While biochar is widely recognised for improving soil health, it is increasingly used in non-soil applications, including construction materials, water filtration, industrial processes, and long-term carbon removal projects.

BIOCHAR DEFINITION

Biochar is a stable, porous form of carbon made from organic biomass through pyrolysis, used to enhance soil performance, improve material properties, and permanently store carbon.

Its durability, surface area, and carbon stability make biochar valuable far beyond agriculture.

HOW IS BIOCHAR MADE?

Biochar is produced using pyrolysis, where biomass is heated to high temperatures (typically 350–700°C) in the absence of oxygen.

THE BIOCHAR PRODUCTION PROCESS:

Sustainable biomass sourcing – forestry residues, crop waste, or organic by-products
Pyrolysis – thermal conversion without combustion
Carbon stabilisation – volatile compounds are removed
Processing and grading – biochar is sized and tailored for different applications

The resulting material is lightweight, highly porous, chemically stable, and long-lasting.

What is Biochar Used For?

Looking at biochar under a microscope, biochar for climate change

Soil & Land-Based Applications:

Improving soil structure and aeration
Increasing nutrient and water retention
Supporting beneficial soil microbes
Enhancing composts and growing media
Regenerative agriculture and land restoration

Non-Soil Applications of Biochar:

Construction materials (asphalt, concrete, plasterboard, insulation)
Carbon-negative building products
Water and air filtration
Environmental remediation
Industrial absorbents and carriers
Carbon removal and long-term storage projects

These applications use biochar’s porosity, surface chemistry, and carbon stability rather than its biological interactions.

Benefits of Biochar Beyond Soil

Biochar’s value comes from its physical and chemical characteristics, not just its biological effects.

Key Material Properties:

Extremely high surface area
Long-term carbon stability
Lightweight and structurally durable
Strong adsorption capacity
Chemically adaptable

These properties allow biochar to improve the performance of materials while reducing their carbon footprint.

BIOCHAR & CARBON SEQUESTRATION

Biochar is increasingly recognised as a permanent carbon removal solution.

When biomass is converted into biochar, much of the carbon absorbed by plants is locked into a stable solid form rather than returning to the atmosphere through decomposition or combustion.

Why Biochar is Effective for Carbon Storage:

Carbon remains stable for centuries to millennia
Suitable for soil and non-soil storage pathways
Can be embedded into long-life materials
Compatible with Life Cycle Assessment (LCA) frameworks

This makes biochar suitable for engineered carbon sinks, not just land-based ones.

Is Biochar Sustainable?

Biochar is sustainable when produced responsibly and matched to appropriate applications.

Sustainable biochar production includes:

Renewable or waste-derived feedstocks
Responsible sourcing and traceability
Controlled emissions during production
Verified carbon accounting and LCAs

Used correctly, biochar supports circular economy models and low-carbon material innovation.

HOW LONG DOES BIOCHAR LAST?

Biochar is exceptionally durable.

In soils: hundreds to thousands of years
In construction materials: potentially longer, depending on application
In sealed or inert uses: effectively permanent

This longevity is what makes biochar suitable for permanent carbon storage, unlike short-lived organic materials.

Why Use Biochar?

Biochar offers a rare combination of advantages:

Long-term carbon storage
Improved material performance
Reduced environmental impact
Compatibility with soil and non-soil systems

From agriculture to infrastructure, biochar enables practical climate solutions across multiple industries.

Learn about uses and benefits of biochar

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Ben Chapman

11:11 28 Feb 24

Great product and service. Have been using Carbon Gold products on lawn, indoor plants, trees and general compost for a... few years now with great results (have been able to save a few near-death indoor plants too). Whilst it is relatively expensive, it stays in the soil and keeps doing it's thing, so over time should become more cost-efficient.read more

Eddie Hawkes

13:29 26 Nov 23

I have noticed a significant improvement in the growth rate and vitality of all the seedlings, flowering, fruiting and... vegetable plants and also the trees, where I have used Carbon Gold to improve their growth. Have just bought more, ready for the winter/spring seasons. Thoroughly recommended!read more

Janet Norman

09:21 26 Apr 23

I have great confidence in the pure vitality of my fruits, flowers, herbs and vegetables when they have been grown in... Carbon Gold composts and fertilisers. The seed and potting on composts are by far my preferred mediums for growing everything in our garden- it feels good to give them a wholesome diet and to be restoring the earth beneath my feet. Delivery from Carbon Gold is also very fast and efficient and I very much appreciate their friendly, personal approach.read more

Teresa N'Guessan

17:49 22 Apr 23

I’ve been using this on my allotment since it first became available years ago. I use it in planting holes when... transplanting into the ground - with amazing results! Other plot holders who gave me seedlings were impressed by how healthy and productive my plants were compared to theirs. Now they’re using it too so we order in bulk. It has helped convert several people to organic growing - so that’s a double bonus!read more

Roberta Bonometti

17:17 09 Feb 23

Bought the bulk bundle for allotments. It arrived the next day. I was very impressed. I can't speak more highly of it.... I grow naturally with a no dig and intercropping method for strong, drought and disease resistant fruit, flowers and vegetables. Because I use lots of carbon gold for lush crops, I would prefer though to be able to buy large 50 kg bags of simple enriched carbon gold, a I used to do in the past, without the different products that now come with the bundle.read more

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