Cambridge Wood Fuel

Cambridge Hotlogs

Video: An introduction to Cambridge Hotlogs

How many Cambridge Hotlogs are there in a 12.5kg bag?

There are twelve or thirteen Cambridge Hotlogs in a 12.5kg bag, depending on the length of the briquettes.

I have a small wood burning stove, and find some briquettes are too big and difficult to break up into smaller pieces.  Will Cambridge Hotlogs fit in it?

Yes – Cambridge Hotlogs are 70mm (about 3”) in diameter and are made in segments about 70mm (3″) long compressed together to form a log up to about 250-300mm (12”) long.  They can be easily broken into smaller chunks to fit a smaller stove, or for when you don’t want to put a whole Hotlog on.

What quality standard are Cambridge Hotlogs made to?

We produce Cambridge Hotlogs to the PrEN14961-3 standard –Fuel specifications and classes – Part 3: Wood briquettes for non-industrial use

How hot are Cambridge Hotlogs compared to firewood?

Hotlogs have a consistently high heat output of at least 4.5kWh/kg (BS EN 14918:200).  The heat output of firewood is variable, depending on the type of wood and how well seasoned it is, and at best around 4kWh/kg.

What is the density of Cambridge Hotlogs, and why is that important?

Cambridge Hotlogs have a density of 1.01(BS EN 15103:2009) – heavier than water and a lot more dense than firewood (which is typically between 0.3-0.5).  The density combined with the low moisture content means that the heat output of one Cambridge Hotlog is at least 4.5kWh – meaning you only need to burn one Cambridge Hotlog per hour in an efficient 4-5kWh wood burning stove.

What is the moisture content of Cambridge Hotlogs?

Typically between 8-12% moisture (BS EN 14774-1:2009 & BS EN 15148:2009). Too dry and they would burn too quickly.  “Seasoned” and”Kiln Dried”  firewood usually has a moisture content of 20-25%.  Unseasoned firewood can have a moisture content of up to 50%

Why is the moisture content and volatile matter of wood fuel important?

More moisture = less heat output, as the heat generated by the fire is used first to drive off the excess moisture in the wood so it will burn. Water moisture should not be confused with volatile matter, which produces heat. Cambridge Hotlogs contain more volatile matter than other briquettes due to the high percentage of feedstock material used from waste timber packaging,  typically pine or spruce, which contains higher levels or volatile organic compounds than hardwoods, such as Ash or Oak.


Can I burn Cambridge Hotlogs overnight in my wood stove?

It might be possible but we would not recommend burning Cambridge Hotlogs or any other wood briquettes slowly overnight, as it could cause problems with your flue.  To get the best performance from briquettes and other wood fuel and your wood stove you need to keep the fire producing flue gas temperatures at around 200°C.  Any cooler and the wood gases are not being burnt off and will form creosote inside your flue.  Too hot  (flue gases above 230°C) and you are wasting fuel and possibly overheating your flue and wood stoveIf in doubt ask your chimney sweep.

How can I make sure I am burning Cambridge Hotlogs at the right temperature?

Buy a stove flue thermometer (we sell these for £12 each) – simply fix it to the flue pipe above the stove and it will tell you what temperature your flue gases are at.

How do I keep my wood stove burning at the right temperature – how often should I refuel it?

Little and often – about one Cambridge Hotlog per hour should do the trick on a wood burning stove rated at 4-5kW.

I have a multi-fuel stove – can I burn Cambridge Hotlogs on it?

Yes, although some multi-fuel stoves are less efficient at burning wood briquettes because they’re designed to cope with burning coal, which can burn a lot hotter and which produces a lot more ash.

Can I burn Cambridge Hotlogs with coal and other solid fuels?

Yes, however like all wood fuels Cambridge Hotlogs burn better on their own or with other wood fuel. Some customers use Cambridge Hotlogs to get their fire going quickly and then put coal on once the fire is nice and hot.

What do you use to bind Cambridge Hotlogs together?

Nothing – the natural lignin in the wood ‘melts’ under the high pressure conditions created in our briquetting press to bind the wood chip and wood dust together.

How do Cambridge Hotlogs compare to, say, a Transit van tipper load of split logs?
Our customers tell us that one tonne of Hotlogs will give you the same heat output of up to three 3.5 tonne tipper loads of logs – because the split logs will have a higher moisture content and are less dense.

What is the ash content of Cambridge Hotlogs and why is it so low?

The ash content is 0.8% or less (BS EN 14775:2009) – meaning you will have to empty your grate less often.  The low ash content compared to other briquettes  is because Cambridge Hotlogs are typically made with high quality used ‘stemwood’, which does not have bark or other extraneous material that would result in more ash.

Cambridge Hotlogs burning in an Efel Harmony 1 stove

Cambridge Hotlogs burning in an Efel Harmony 1 stove

Why do you package Cambridge Hotlogs in heavy duty polythene bags? Wouldn’t paper or cardboard packing be better for the environment?

Because of the low moisture content, Cambridge Hotlogs need to be kept dry, especially if stored outdoors, otherwise they would take up moisture and expand.  We have looked at all the different kinds of packaging available and cannot find a better alternative to the advanced polymer bags we use.  These advanced polymers are much stronger than ‘recycled’ plastics, meaning they use less raw material.  We’ve made sure the bags we use are just big enough to hold 12.5kg of Cambridge Hotlogs, in order to use the least amount of polythene. And we give you 12.5kg of Hotlogs in a bag the same size or smaller than our competitors, who typically package them in 10kg bags of wood briquettes.

Can I use Cambridge Hotlogs in my Chimenea / fire pit?

Yes – Cambridge Hotlogs are the ideal fuel for Chimeneas and firepits as they are easy to light, produce very little smoke and burn out completely leaving very little ash.