2 big questions

[barry ayres]

1. If you had the exact same size log and species e.g a beech log 10 inches by 4 inches but one kiln dried and one naturally air dried both at 20% moisture which would last longer? 
 

2, if you had all hardwoods and Are dried to 20% which would last the longest?

[Squaredy]

25 minutes ago, barry ayres said:

1. If you had the exact same size log and species e.g a beech log 10 inches by 4 inches but one kiln dried and one naturally air dried both at 20% moisture which would last longer? 
 

2, if you had all hardwoods and Are dried to 20% which would last the longest?

I don't think it matters how firewood is dried as long as it is dry.  I would say however they would not be dried the same.  The kiln dried log would be much drier than 20% on the outside, but depending on how long it was kilned for could be higher than 20% inside!

 

In reality most kiln dried wood is drier than most air dried wood, but there are exceptions of course.

[Stere]

Silly questions as what does last longer mean?

 

If you mean in a fire the wet log will burn slowest...

 

Best soak them in a bucket of water first if you want logs to last a long time.

 

 

Edited March 1, 2020 by Stere

[barry ayres]

Okay let me explain, last longer means which method of drying wood of the same species will last longer burning in a fire ( as it is a firewood forum) there was no mention of wet wood, personally I believe that air dried logs have more guts ( last longer) then kiln dried logs and I believe that Holm oak at 20% will last then any other wood but I want other people’s opinions 

Edited March 1, 2020 by barry ayres

[Rough Hewn]

Kiln dried logs will burn quicker but only slightly,
As the kilning process will split the log make splinters rise etc making there more surface area to burn.
Generally an air dried log will have dried much slower, and if not exposed to sunlight will have cracked and split less.
[emoji106]

[Rough Hewn]

1. If you had the exact same size log and species e.g a beech log 10 inches by 4 inches but one kiln dried and one naturally air dried both at 20% moisture which would last longer? 
 
2, if you had all hardwoods and Are dried to 20% which would last the longest?

Ton of feathers or ton of lead which is heavier kind of question.
[emoji106]

[gdh]

If they're both the same moisture they should produce the same KW. How it's dried won't make much difference.

[Peasgood]

I would expect some difference if you were comparing a log fairly fresh out of the kiln with an air dried log that has got down to 20%. After not very long stored in the same conditions they would be exactly the same because both will change according to atmospheric moisture anyway.

[barry ayres]

Just off the back off my own experiments I found that a air dried log of the same size and species last 5-10 minutes longer, and that Holm oak gives of a lovely flame and lasts longer then beech, ash, English oak and apple, but I want to know what you think? And as far as I know there’s been no test done on this

[Steven P]

So if I read the question right, you have 2 very similarly sized logs, when you split them both and checked their moisture levels from the centre of the log they both read the same 20%, then you put them both on the fire, whch one would burn the slowest? Should be both the same, how they are dried makes no difference really.

 

Now if you are finding the air dried log burns slower than the kln dried log then there is a reason for it and the only real variable is that the air dried log is wetter (higher moisture content) than the kiln dred log.

 

 

I am guessing your second part of the question is really gven the choice what hard wood log should you buy? For this you will get many answers, we all have our favourites (I really like thorn - hawthorn, blackthorn and so on, others will swear by oak, or ash). Pretty much (with some exceptins) 1kg of wood at 20% moisrure has the same energy as most other wods at 1kg and 20% (16MJ per kg according to google just now, just over 5,000kwH per tonne of kiln dried wood).. however we buy wood by quantity (builder bag, tipper truck, 'load' and so on) and here you should look for the most dense woods to get the best value. Softwoods are considered 'bad' because they are the least dense (generally) and so the least energy per delivery, Something like this link could help here https://solidfuel.co.uk/pdfs/GUIDE-TO-WOOD-AND-MULTIFUEL-SEP19.pdf and you can find expanded tables but load for lod oak is pretty good for heat output.