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Biochar versus charcoal - is there a difference? The unbiased facts revealed by SoilFixer

Tony Callaghan 20/02/2022

Biochar versus charcoal - is there a difference? The unbiased facts revealed by SoilFixer

Biochar versus charcoal - is there a difference?

We provide a tabular summary to guide you through the maze and explain the detail to help you make an informed decision. 

The answer to these questions should be simple and based on fact. Even so, we find some biochar and gardening websites stating there is a huge difference and that charcoal cannot be used as biochar for soil. Some sites even imply that doing so would damage your plants.  Other sites advocate charcoal is exactly the same as biochar and can be used safely.  To those knowledgeable in both charcoal and biochar production methods, there also appears to be bias according to the producer's equipment and primary product offering!

There are subtle differences that determine the answer. Buyer beware - not all biochars and lump charcoals are made equal.

We provide high quality biochar for sale from our website that may be suitable for your needs!

What's the difference between biochar and lump charcoal? 

Chemically and physically, in almost all cases, there is absolutely no difference between biochar and charcoal. Both can work equally well and equally badly if not applied correctly.

However environmentally, in terms of sustainability, air pollution, and heat recovery (efficiency), there is often a HUGE difference between charcoal and biochar.

(For those with a science background: we have assumed that the charcoal and biochar being compared are made using the same time and temperature profile).

What is charcoal

Charcoal is a carbon char made from wood heated in the absence of oxygen. The technical term for this process is pyrolysis and the older more common name is charring and charcoal making. In most classifications (e.g. customs, shipping, packaging, chemical hazard coding), charcoal means char derived from wood intended solely for use as a fuel. (In Europe that fuel is almost exclusively for BBQs).

To be useful as a BBQ fuel, lump wood charcoal needs certain qualities. This means most charcoal is made within a narrow temperature profile over a closely monitored time scale (12-18 hours) using mainly 'hard woods'. 

Lump charcoal is a different material from BBQ briquettes. BBQ briquettes are made from powdered material compressed into a formed shape - normally an oval but it can be long tubular forms. BBQ briquettes (fuel) can be made from many things including coal dust and powdered charcoal. Powdered charcoal does not stick or mold into lumps well so clay (soil!) is added as a binder. Clay does not light (combust), so often cheap briquettes have accelerants added to help them ignite.  (Many sites claim accelerants and additives are detrimental to soil - but most are not.)  

 The safest way to ensure 'charcoal' can be used as 'biochar' is to only buy EBC certified biochar. 


What about biochar

Read our original article titled 'What is biochar' to learn what it is!

Biochar terminology versus charcoal

This is the crux of the issue - the term biochar is defined by its use for environmental benefit, not just by its chemical and physical properties. It must be:

Produced by a non-polluting system

If your charcoal has been made in old technology such as a fire pit, ring-kiln, or any other process (new or old) that does not retort volatile organic gases (released during heating) converting them into carbon or does not have the technology to remove all volatile organic chemicals to part per million level from the exhaust gas, then it will pollute the atmosphere with gases that are significantly worse for climate change. The wood may as well have been left to decompose to carbon dioxide! 

From a sustainable resource

Wood is a renewable resource but it is not always a sustainable resource. Careful planning of the volume cut versus planted and growth over long-time frames are needed. Typically wood-derived-biochar will only ever be made from FSC certified wood, and even then preferably only FSC wood parts such as brash and toppings that have limited other uses. There are some companies now seeking to use truly 'end of life,  waste wood' that is no longer suitable for reuse.

Produced with high Energy efficiency

When you make biochar (or charcoal) heat is released. A biochar process is defined by its efficient use of this heat. It is not acceptable for all the heat to go up the chimney stack to be released (and wasted) to the atmosphere. A biochar system has to be certified as efficient whereas a charcoal system does not - as it only has to produce quality fuel.

The UK imports 95% of all the 100,000 tonnes of lump charcoal sold in the UK each year. We know and have spoken to many of the UK charcoal makers. Most operate old traditional ring kilns and only a small number have 'retort kilns' that could achieve EBC biochar certification.

No matter where the char came from and what process is used, the European Certification scheme has your back. The safest way to ensure your 'charcoal' can be used as 'biochar' is to only buy EBC certified biochar.


Q & A

  • Can I use charcoal as biochar? Yes in some cases, no in other cases
  • Can lump charcoal be used as biochar? yes in many cases, no in some cases
  • Can I use BBQ briquettes as biochar? No in most cases, yes in some rare cases

Some common myths

Charcoal made at low temperature contains 'volatiles' in the char but biochar does not

Wrong!. Pyrolysis occurs between 300C and 1000C. It can take place in seconds (flash pyrolysis) or many hours (e.g. 24 hours heating and cooling lump wood charcoal). At lower process temperatures, some volatile chemicals can remain in the char. Experienced lump charcoal and biochar makers ensure all volatiles are removed using longer process times where needed.

The potential toxic volatiles are grouped as "BTEX" and "PAHs". There are strict limits (down in the parts per billion level) that biochar must meet. It is really simple: if your supplier is EBC certified they meet the strict limits. If they are not certified, ask for a lab report on the BTEX and PAH levels and compare them to the certification scheme.  Any supplier serious about charcoal/biochar for soil will be 'all over' these figures and ensure their product is safe and fit for purpose. 

The carbon content is different in charcoal and biochar / Lump charcoal has less carbon than biochar

Wrong! Chars can have a carbon level from 40-95%. It depends on the feedstock, process equipment, and time and temperature achieved.  Your supplier should be analysing the percentage of carbon. It is a mandatory item in the IBI/EBC certification.   Depending on use, there are pros and cons of different carbon levels. (Our advice is to look for a figure above 75%). 

Charcoal carbon is less stable than biochar carbon

Wrong! When looking at mitigating climate change and offsetting carbon dioxide then how long the carbon stays in the soil is important. If you add compost it will fully decompose in 2-10 years. Chars can last anywhere from 100-1000 years depending on conditions. The IPCC has agreed on a standard C-Stability method with the biochar industry. It uses the ratio of hydrogen to carbon in the biochar. The lower the ratio, the more stable to biochar. Biochar certification determines the Hydrogen to Carbon ratio and this is used in the lifecycle analysis and gives each manufacturer an agreed offset figure. (This is why some biochars offset 1kg of CO2 and others offset 3 Kg CO2 per Kg char. 

Is my charcoal/biochar contributing to deforestation?

Check that the producer only uses sustainable wood resources e.g. - FSC. (not 100% guarantee. but best we have). We have said it many times  -  The safest way to ensure your 'biochar' is sustainable is to buy EBC certified biochar.

 So now we can create a matrix  comparing biochar and charcoal to determine fit for purpose

Earth pit 

Certifiable as biochar

Ring Kiln

Certifiable as biochar

Advanced Retort

Certifiable as biochar

Advanced pyrolysis

Certifiable as biochar

Made from FSC wood


Yes, FSC wood









Made from other organic matter

(e.g. coco, psk, straw, miscanthus)

Non-sustainable resource

Certified sustainable feedstock?









Is the biochar activated? (1)
nonono (2)
Is the biochar co-composted with green waste? (3)

Is the biochar/charcoal carbon stable in soil?

(i.e. sequester carbon to offset climate change?

When used correctly, does the carbon enhance plant growth?


(1) All serious biochar producers recommend biochar is 'activated' before adding to soil.  (2) There are some R&D pyrolysis units looking at 'activation' within the process, but we are not aware of any commercially made.  (3) The latest meta-data suggests the best way to use biochar is to co-compost it with green waste and use the final compost-biochar mix.  (SoilFixer pioneered co-composting, and testing and advocated this method seven years ago. Our 'SF60 humification'  methodology is in the final stages of European Patent Approval.)

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