Looking for a biochar vs charcoal comparison?
Biochar and charcoal are similar carbon based materials that are often confused with each other. However, they have very different applications, properties, and production processes.
In this article, we’ll discuss the six key differences between biochar vs charcoal to help you determine if charcoal is a replacement for biochar. We’ll also show you the best biochar product for your garden.
This Article Contains:
(click on a link below to jump to a section)
- Biochar vs Charcoal: 6 Key Differences
- Can You Use Charcoal Instead of Biochar for Gardening?
- The Best Biochar Product: Rosy Biochar’s Potting Mix
Biochar vs Charcoal: 6 Key Differences
Gardening and carbon sequestration
Produced via a modern pyrolysis method at 840-1200°F (450-650°C)
Produced via both old and modern pyrolysis methods at 750°F (400°C)
All types of biomass feedstock
Wood or plant material
Greater porosity and surface area
Lower porosity and surface area
pH between 4.6-9.3
pH between 9-11
By mixing with organic matter
By heating at high temperature with gases
Let’s explore these differences in detail.
Here’s how biochar and charcoal differ in their applications:
Biochar, sometimes called horticultural charcoal, is usually used to:
- Improve soil fertility and soil structure, helping you revitalize poor soil and increase crop yield.
- Facilitate carbon sequestration (capturing atmospheric carbon dioxide and trapping it in the soil) and increase soil carbon content.
- Improve animal health by adding it to livestock feed.
- Reduce the carbon footprint of construction materials like concrete and asphalt.
Read more about biochar and its uses here.
Charcoal is mostly used as a fuel for cooking and heating.
Since it can burn at high temperatures exceeding 2,010°F (1,100°C), it’s also useful for smelting iron or other metals like bronze.
Additionally, once you activate charcoal, you can use it for water filtration and medicinal purposes.
Both biochar and charcoal are made via pyrolysis — the thermal decomposition of organic material like plant waste into carbon in the absence of oxygen.
However, they still differ in the way they’re made. Here’s how:
Biochar is typically made using the modern pyrolysis method. It uses the heat released from the combustion of gases to facilitate pyrolysis.
The process occurs between 840-1200°F (450-650°C) and is relatively fast, taking minutes to a few hours to produce biochar — along with byproducts like syngas, a great fossil fuel alternative.
The Intergovernmental Panel on Climate Change lists biochar production as a negative emission technology as it helps reduce greenhouse gas emissions and slow down climate change.
Unlike biochar, charcoal can be produced by either the old or modern method of pyrolysis.
The old method involves using a carefully arranged pile of wood and a chimney to facilitate the thermal decomposition of wood into charcoal in the near absence of oxygen.
Unlike biochar production, charcoal production occurs at a lower temperature, around 750°F (400°C), and can take days to complete.
Moreover, pyrolysis gases and polycyclic aromatic hydrocarbon compounds are released during charcoal production. This increases atmospheric carbon dioxide levels, making it a positive emission technique, which is harmful to the environment.
3. Source Material
Let’s now compare the feedstock used in biochar and charcoal productions:
Biochar is produced from biomass or organic material like agricultural waste, plant residues, wood chips, etc.
Charcoal is derived primarily from wood-based biomass and can be classified into:
- Common charcoal: produced from wood, peat, coconut shell, and petroleum.
- Lump charcoal: made by burning hardwood material.
- Sugar charcoal: made from cane sugar.
- Barbecue charcoal briquettes: produced from sawdust and leftover wood material.
4. Physical Properties
Both biochar and charcoal are amorphous (without a fixed shape) black carbon forms with thousands of pores and grooves.
However, they have subtle differences in their physical properties:
Biochar is more porous and has a larger surface area than charcoal — a few ounces of biochar can have an internal surface area the size of a football field!
This porosity and surface area helps biochar improve soil structure and house beneficial microbes, resulting in healthy soil.
Due to its low production temperatures, charcoal has lower porosity than biochar. This temperature also results in a less stable form of carbon, meaning it decomposes in the soil faster than biochar.
Charcoal also has low thermal and electrical conductivity, making it useful as an insulator.
However, these physical properties depend on the source material and temperature used during charcoal production.
5. Chemical Properties
Here’s how biochar and charcoal differ in their chemical properties:
Depending on the feedstock source, biochar may have varying levels of macronutrients (like Phosphorus) and micronutrients (like Zinc) that are essential for plant growth.
It’s usually alkaline, but depending on the source material and production temperature, it can have a pH between 4.6 to 9.3.
- It has a negative charge that helps increase the cation exchange capacity (ability to hold nutrients) of soil, improving plant nutrient availability.
Charcoal usually contains less than 1% moisture, but it can increase to 5-15% by absorbing moisture from the air. Higher moisture levels reduce the heating efficiency of charcoal.
- Activated charcoal is more alkaline than biochar, with a pH range of 9-11. This helps it absorb organic material in water.
To improve their properties, you can activate biochar and charcoal.
For best results as a soil amendment, biochar needs to be activated or charged with nutrients and microbes before being applied to soils.
Biochar activation typically includes mixing a 1:1 ratio of raw biochar and nutrient-rich organic matter like compost. The mix is then kept aside for around two weeks so that it’s loaded with nutrients, moisture, and soil microbes that can improve soil health.
Find out everything about how to activate and use biochar.
Activated charcoal (activated carbon) is made by heating common charcoal at high temperatures in the presence of gases like Argon, Nitrogen, or steam.
This gives it a larger surface area and porosity than normal charcoal and biochar, enhancing its adsorption potential and capacity for filtration.
However, activated carbon lacks other properties suitable for plant nutrient uptake, like ion exchange.
Can You Use Charcoal Instead of Biochar for Gardening?
Due to its unique properties, biochar is a better organic gardening resource than charcoal.
In fact, biochar’s use as a soil amendment is based on terra preta — a fertile soil used 2000 years ago in the Amazon basin. Terra preta soils helped transform poor soil into healthy soil, improving soil productivity and crop yield.
On the other hand, charcoal briquettes contain wood ash and harmful chemicals. These additives can reduce soil pH and negatively impact microbes and soil productivity.
That’s why charcoal can’t replace biochar for gardening.
So, if you want to boost your soil and plant health, you need to use biochar.
But what biochar should you use?
The Best Biochar Product in 2022: Rosy Biochar’s Potting Mix
Rosy offers an easy-to-use Biochar Potting Mix — a clean, sustainable product made from single-source lumber waste.
It's peat-free and comes pre-activated with plant-based compost and endomycorrhizal fungi that quickly improve plant growth in your garden.
So, you can skip the activation period and supercharge your garden by simply adding the Potting Mix directly to the base of each plant or mixing it into the soil.
You’ll see your garden thrive.
Biochar and charcoal are two very different materials.
While charcoal is suitable for heating purposes, biochar is a great organic gardening resource.And when it comes to biochar, there’s no better product than Rosy’s eco-friendly and sustainable Potting Mix. Why not grab a bag to nourish your garden today?