They look similar, but biochar and charcoal serve very different purposes. Here’s what you need to know.
The Quick Answer
Biochar is made specifically for soil improvement. It’s produced through controlled pyrolysis to optimize porosity, stability, and soil benefits.
Charcoal is made for burning. It’s produced to maximize energy content and combustion properties.
Same basic process, different goals, different results.
Understanding the Confusion
Biochar and charcoal are both created by heating organic material in low-oxygen environments. They’re both black, lightweight, and carbon-rich. At a glance, they can look identical.
This similarity leads to a common question: “Can I just use BBQ charcoal in my garden?”
The short answer is no, and understanding why helps explain what makes biochar special.
Side-by-Side Comparison
| Factor | Charcoal | Biochar |
| Primary purpose | Fuel for burning | Soil amendment |
| Optimised for | Energy release | Soil benefits |
| Production goal | High heat output | High porosity and stability |
| Typical feedstock | Dense hardwoods | Various biomass |
| May contain | Accelerants, binders | Nothing added |
| Soil safety | Not recommended | Designed for soil |
| Carbon stability | Released when burned | Stable for centuries |
| Price point | Lower | Higher (reflects production costs) |
How Production Differs
Charcoal Production
Traditional charcoal production prioritizes: – High energy density: More heat per kilogram – Easy ignition: Lights quickly and burns evenly – Long burn time: Sustained heat for cooking – Low cost: Mass production efficiency
To achieve these goals, charcoal is often produced at higher temperatures (600-900°C) and may include additives like accelerants or binding agents. The internal structure is less important than combustion properties.
Commercial charcoal briquettes frequently contain: – Coal dust – Sodium nitrate (accelerant) – Limestone (to control burn rate) – Starch (binder) – Sawdust
These additives help charcoal perform as fuel but make it unsuitable for gardens.
Biochar Production
Biochar production prioritizes: – High porosity: Maximum surface area – Carbon stability: Resistance to decomposition – Consistent quality: Predictable soil effects – Clean material: No additives or contaminants
Biochar is typically produced at moderate temperatures (400-600°C) through controlled pyrolysis. The process is optimized to create the porous structure that gives biochar its soil-improving properties.
Quality biochar contains only carbon and minerals from the original feedstock—nothing added.
Why the Differences Matter for Soil
Porosity and Surface Area
Biochar’s value comes largely from its internal structure—microscopic pores that provide massive surface area for water and nutrient retention, and habitat for beneficial microorganisms.
A single gram of quality biochar can have a surface area equivalent to a tennis court. This porosity is deliberately created through controlled pyrolysis conditions.
Charcoal, optimized for burning, doesn’t require this internal structure. Its porosity is incidental rather than intentional.
Contaminants
BBQ charcoal often contains compounds that shouldn’t be in your garden: – Heavy metals from industrial feedstocks – Chemical residues from accelerants – Binding agents not tested for soil safety – Ash that may alter soil chemistry unpredictably
Biochar from reputable producers is tested for contaminants and produced from known, clean feedstocks.
pH and Chemistry
Both biochar and charcoal are generally alkaline, but biochar’s pH is controlled and documented. BBQ charcoal’s pH can vary widely depending on additives and production methods.
What About Lump Charcoal?
Lump charcoal (pure carbonized wood without additives) is closer to biochar than briquettes. Some gardeners have used it successfully.
However, lump charcoal still isn’t optimized for soil use: – Porosity isn’t controlled – No quality testing for soil applications – May be produced from treated or contaminated wood – Properties vary batch to batch
If you’re investing in soil improvement, purpose-made biochar is worth the additional cost.
The Activated Carbon Question
Activated carbon (activated charcoal) is another related material that sometimes confuses.
Activated carbon is processed beyond regular carbonization. After pyrolysis, it undergoes “activation”—treatment with steam, acids, or other chemicals that dramatically increases surface area and adsorption capacity.
Activated carbon is used for: – Water filtration – Air purification – Medical treatment (poison absorption) – Industrial processes
While activated carbon has an even higher surface area than biochar, it’s unnecessary (and expensive) for garden use. Biochar provides all the soil benefits at a fraction of the cost.
Can You Make Your Own Biochar?
Technically, yes. Small-scale biochar can be produced using: – Cone kilns (TLUD design) – Retort systems – Pit burns (traditional method)
However, DIY biochar has limitations: – Variable quality and properties – No testing for contaminants – Inefficient use of biomass – Fire risk and smoke production – Time-intensive process
For most gardeners, purchasing quality biochar is more practical than making your own.
What About Using Fire Pit Charcoal?
Charcoal from your fire pit or wood stove can be used in small amounts if: – Only untreated, unpainted wood was burned – No accelerants (lighter fluid) were used – The charcoal is crushed finely – You’re using small amounts mixed with compost This “found charcoal” won’t have the optimised properties of proper biochar, but it’s safe and provides some benefits. Think of it as a minor soil addition rather than a serious biochar application.
Making the Right Choice
Choose Charcoal When:
- You need fuel for cooking or heating
- Energy density matters
- You’re burning, not amending soil
Choose Biochar When:
- You want to improve soil health
- Water retention is a priority
- You’re building long-term soil carbon
- Consistent, tested quality matters
Avoid Using in Soil:
- BBQ briquettes (contain additives)
- Charcoal of unknown origin
- Charcoal from treated or painted wood
- Any charcoal with chemical residue
The Bottom Line
Biochar and charcoal share a basic production process, but the similarities end there. Charcoal is optimized to release energy when burned. Biochar is optimized to improve soil indefinitely.
Using BBQ charcoal in your garden isn’t just less effective—it may introduce unwanted chemicals and produce unpredictable results. Purpose-made biochar costs more but delivers reliable, documented benefits.
When it comes to your soil, invest in the right material for the job.
Looking for quality biochar? B10 produces premium, pre-charged biochar specifically designed for agricultural use. Made from clean waste biomass in Mpumalanga, South Africa, our biochar is tested, documented, and ready to improve your soil. Learn more or contact us
Related Articles: – What is Biochar? The Complete Guide – 10 Proven Benefits of Biochar for Your Soil – How to Use Biochar in Your Garden
Last updated: January 2026
