Help moisture content in logs

Mister_G

My sweep advises to only burn logs with less than 20% moisture.

Greenfires

First off - over 30% mc would not be considered "seasoned" by any measure I've ever come across. BUT - how are you measuring the moisture content? If the logs have been outside and have been rained on recently - if you stick a moisture meter in the outside of one you'll get a high reading. This isn't the way to measure it though. You need to split a log and then take a reading on one of the freshly exposed surfaces - not by sticking the probes into the end grain or an outside surface. Dry logs that get a bit of rain on do not generally end up soaking wet again - it's only the outside that gets wet.

Kiln dried logs are a fantastic bit of marketing to make a bigger profit. Most kiln driers are big commercial outfits shifting thousands of tonnes of wood a year. They don't have the space to sit on all that wood and let it dry naturally, so they bung it in a kiln straight out of the forest. A bit later it's drier than it was, it gets removed and sold as the "finest logs you can buy" at a whopping premium. Most commercial driers work to an average moisture content of 20%. In a good drying year such as we've had this year for instance, naturally dried logs from the old boy down the road may well be several percentage points drier than the kiln dried stuff - but without the hefty price hike!

As far as briquettes go - the verdo ones are okay if you're buying purely based on the price tag. You need to remember though that there's as much difference between different types of briquettes as there is between logs, and that there are much better ones out there. They may be more expensive on paper - but if they last twice as long then in real terms they often work out cheaper. We sold cheap briquettes one year alongside our usual ones, and although all our regular customers thought they were okay, nobody bought them twice. They all said they thought the "expensive" ones worked out cheaper to use as they lasted so much longer, which pretty much confirmed our own feelings (we only sell stuff we use ourselves) We certainly don't have any plans to repeat the exercise anyway!

In terms of moisture though ANY briquette will make a log - kiln dried or otherwise - look like a damp sponge. That's why a kilo of briquettes will always give a lot more heat than a kilo of logs.

suisidevw

Just to confirm, you are also splitting one of your logs and measuring the inside of the log on the cut face, not the end aren't you?

They clearly aren't seasoned so I'd be having a chat to your supplier!

Smiley_Dan

My experience of "seasoned" logs from local suppliers is the same as the OP. I gave up and now season my own, using briquettes in between times.

suestew

right very interesting thanks all.

I am using a moisture metre and we do split the logs and the readings are from 30-38 still. I don't stick it in the end of the log either.

So can someone advise, if our logs are currently at around say 35% approximately how much longer should they be outside to get down to a suitable moisture level?

And lastly do you get a good flame with the briquettes?

Robwiz

suestew wrote: »

right very interesting thanks all.

I am using a moisture metre and we do split the logs and the readings are from 30-38 still. I don't stick it in the end of the log either.

So can someone advise, if our logs are currently at around say 35% approximately how much longer should they be outside to get down to a suitable moisture level?

And lastly do you get a good flame with the briquettes?

You'll need another 12 months – most of the drying out happens when the weather is warmer and drier, which is the summer. They will be ready to burn this time next year.

Yes you get a very good flame with the briquettes. A nice orangey red, depending on how much air you let in the stove and how quickly they burn. As a comparison, the Verdo published specification for moisture content is 8%.

Robwiz

Greenfires wrote: »

As far as briquettes go - the verdo ones are okay if you're buying purely based on the price tag. You need to remember though that there's as much difference between different types of briquettes as there is between logs, and that there are much better ones out there. They may be more expensive on paper - but if they last twice as long then in real terms they often work out cheaper. We sold cheap briquettes one year alongside our usual ones, and although all our regular customers thought they were okay, nobody bought them twice. They all said they thought the "expensive" ones worked out cheaper to use as they lasted so much longer, which pretty much confirmed our own feelings (we only sell stuff we use ourselves) We certainly don't have any plans to repeat the exercise anyway!

A retailer recommending a more expensive product – quelle surprise!

My experience is the opposite of your customers. I started off with Verdo briquettes and found them perfectly satisfactory. Verdo is probably the number one manufacturer of wood pellets and their briquettes are produced in the same factories from the same raw materials.

The Verdo briquettes give off good heat (4.8 kW/kg) and I'm very happy with how long they burn. I personally don't see any reason to buy a more expensive product which would result in a higher cost per kilowatt hour of heat output. I'd guess that the higher prices go mostly towards marketing and dealer profit margins.

suestew

thanks all, I have certainly learned a lot from this post, I knew the wood wasn't good enough when you compared it to the dry that we used, I just need to get my husband to listen to me as he seems to think he can still light a fire with these logs.

Robwiz

suestew wrote: »

thanks all, I have certainly learned a lot from this post, I knew the wood wasn't good enough when you compared it to the dry that we used, I just need to get my husband to listen to me as he seems to think he can still light a fire with these logs.

He's right up to a point. You could light a fire with those wet logs but you'd lose a lot of the heat energy turning water to steam and have a very good chance of lining your flue with tar leading to a chimney fire.

silverwhistle

I'm a new user of a wood burner too, but I started collecting wood last year and after this summer the moisture level of most of my processed (cut to length and split) and covered wood is ~20%. Some I've left stacked and uncovered but that's for processing next spring/summer.

33 -38% isn't seasoned though, by any measure, so I'd knock them off your list. It's best to check just before your supplier unloads the wood: split a log and measure the moisture. If you ask on the phone for approximate moisture % they'll know they can't dump any old rubbish on you.