How to make your own wood vinegar with a Cookswell Kiln

How to make your own free wood vinegar and Stockholm tar with the Cookswell Smoke Trap and a Kinyanjui Kiln.  (Avalible from

What is wood vinegar? 

Recovery of chemicals from the vapours given off when hardwood is converted to charcoal was once a flourishing industry. However, as soon as the petrochemical developed, wood as a source of methanol, acetic acid, speciality tars and preservatives became uneconomic. But with the advent of higher prices for organic food and organic living, wood vinegar is making a vigorous  globally resurgence.  

Wherever charcoal is made the possibility of recovering by-products should be discussed.

By adding a simple metal pipe to a large 140$ Cookswell drum kiln - you can collect appx. 1-2 liters of wood vinegar per 9 hour cycle while producing appx. 20-35kgs of lumpwood charcoal from appx.80kgs of air dried wood. 

Wood vinegar is another name for pyroligneous acid and is the crude condensate of smoke that consists mainly of water. 
The non-water component consists of wood tars, both water soluble and insoluble, acetic acid, methanol, acetone and other complex chemicals in small amounts. When left to stand, the pyroligneous acid separates into two layers comprising the water insoluble tar and a watery layer containing the remaining chemicals.

Simple decant it into bottles and let the tars settle for 12 weeks or so. 

Specific Farm Uses for Wood Vinegar:

The Appropriate Technology Association of Thailand recommends the following wood vinegar/water solution rates for various farm uses:

• Repel nematodes – Tomatoes, 1:500 (apply to the base of plants); strawberries, 1:200 (apply to the base of plants); and black pepper vines, 1:1500 (apply in place of water).

• Repel insect pests – Cabbage and Chinese cabbage, 1:1500 (apply in place of water); corn 1:300 (spray onto leaves).

• Control of fungal diseases – Tomato and cucumber, 1:200 (spray onto leaves).

• Control of root rot – Tomato and cucumber, 1:200 (apply to the base of plants).

• Reduce incidence of chili pepper flowers aborting – 1:300 (spray onto leaves).

• Improve flavor of sweet fruits and stimulate development of crops. Mix solution rates of 1:500 to 1:1000. Wood vinegar prevents excessive nitrogen levels, improves plant metabolism and contributes to higher fruit sugar levels.

• Stimulate compost production. A solution rate of 1:100 will help increase the biological activity of various beneficial microbes and can decrease composting times.

• Combat bad odor. A wood vinegar solution of 1:50 will diminish the production of odor-causing ammonia in animal pens.
• Supplement for livestock feed. Mixed with livestock feed at rates of between 1:200 and 1:300, wood vinegar can adjust bacterial levels in the animal digestive tract which improve the absorption of nutrients from feed.

• Enrich garden soil. Use a strong solution of 1:30 to apply to the garden soil surface at a rate of 6 liters of solution per 1m² to enrich the soil prior to planting crops. To control soil-based plant pathogens, use an even stronger rate of application. 

Composition and Characteristics of Wood Vinegar

Nikhom reports that wood vinegar yield per metric ton (2200 lbs.) of air dry wood is appx. 314 kg (690.8 lbs.). The product contains approximately200 components. 

These include:
• Alcohol (methanol, butanol, amylalcohol)
• Acid (acetic, formic, propioinic, valeric)
• Neutral substances such as formaldehyde, acetone, furfural, valerolactone
• Phenols (syringol, cresol, phenol)
• Basic substances such as ammonia, methyl amine, pyridine

He also describes quality wood vinegar as having the following characteristics (most of which may require special laboratory instruments
or methodology to determine):
• pH of approximately 3.0
• Specific gravity between 1.005-1.050
• Color ranging from pale yellow to bright brown to reddish brown
• Transparent
• Smoky odor
• Dissolved tar content: less than 3 percent
• Ignition residue: less than 0.2 percent by weight

Your own homemade wood vinegar will vary depending on the feedstock used, moisture content and carbonization time. We recommend you do trials before large scale use.

A 2 hour cooling phase of the kiln before extracting the lumpwood charcoal

Wood vinegar and charcoal making during de-bushing for pasture improvement. Another by product is Stockholm tar for the cattle and horses hooves. 

And with many thanks to Kenya - we are also including a packet of indiginous acacia xanthopholea and kirkii tree seeds so you can grow a life time supply of free woodfuel, wood vinegar, biochar and tar.

For more information about wood vinegar - please see these links below:

Please get in touch with us at if you have any suggestions, comments, questions or would like to pick some up for a trial for free!