Lump Charcoal is carbonised wood, it’s made by super-heating wood and driving the moisture out. The actual carbon content of charcoal varies with the manufacturing process and the wood used.
Lump charcoal is typically 65-75% carbon, High-end charcoal like Japanese Binchotan can be as high as 95% carbon. This density of carbon dictates how the charcoal burns. Binchotan is difficult to light but yields a super-hot, clean burning fire as a result of the “wood vinegar” (pyroligneous acid) being removed.
It’s the same with the manufactured briquettes. Briquettes vary as much as lump does but typically the carbon density is 75-85%
Buying charcoal is about knowing what you want it to do, and for how long.
A less dense charcoal like Big Green Egg imported Oak and Hickory will come up to temperature quickly and in a controlled airtight environment like a Kamado or Drum smoker will give you good control and fast response to vent changes, in the open air like a spit however it will burn hot and fast.
A denser charcoal like Mallee or Acacia is slower to get going and slower to respond to vent changes but the same volume of fuel will last longer, it will burn hot in the open air but for longer.
So, think about both the bag size and weight when buying charcoal, not just the weight.
To illustrate that point, here is the 9kg BGE charcoal beside a 18kg bag of Acacia. You can see they are roughly the same size but the weight (density) is completely different.
Pillow type Briquettes are made to a formula, most are a sawdust and carbon dust bound together with a binder like starch, some contain coal dust, others have carbon dust from other manufacturing process. Some contain, among other compounds, Sodium Nitrate as an ignition agent, this also helps to create a “smoke-ring” and Limestone to whiten the ash. Because they are manufactured, they serve different purposes, some are dense and burn hot and clean, others have wood dust or other additives to produce a flavoured smoke and/or a slower or faster burn rate.
Extruded Charcoal “logs” are generally just carbon and wood dust held together by heat and pressure of the extruding process, these are dried then carbonised. This form of manufactured charcoal produces no smoke, no odour, little ash, burns with high heat, and has a long burning time (exceeding 4 hours).
At the end of the day, it’s you who are in control, what you use is your choice.
You can mix and match is you want to, you could construct your Snake or Fuse so the start is one kind and the finish is another kind.
Often, I will fill my Big Green Egg with Acacia or Mallee and top with a small handful of BGE because the BGE will get going quickly and establish my fire fast, other times I just use the BGE because I want the taste it gives and the rapid control when I need to change the temperature
Lighting your Charcoal
I’m not a big fan of using firelighters inside me BBQ or Smoker.
Particularly with a ceramic Kamado or Big Green Egg, the fumes from the firelighter can impregnate the ceramic.
If you do use a firelighter, be sure it is completely burnt out before closing the lid or cooking
I prefer to use a starter wand or a chimney to start my charcoal.