Windy biochar

I burned biochar 2 days ago for the first time this year.  Overall it worked well, but I wonder about something.  I watched to make sure it would be sunny, but I didn't watch for wind.  It was so windy that it knocked off my chimney a few times and damaged it.  I think I can fix it, but I wonder if there are adjustments that we might make for burning biochar in the wind.  

Is there an amount of wind beyond which you don't burn biochar? I was a little worried that a spark could go somewhere, but it's covered with a chimney and the wind was just blowing it onto cement.  I burn it in my driveway.  

Please let us know about adjustments or limits that you use when burning char in the wind.
Thanks,
John S
PDX OR

Honestly, I'd happily have a bonfire, or make biochar, in the rain. Sunny is more pleasant, but not essential. I'd even go so far as to actively avoid bonfires on sunny days as the neighbours are more likely to be using their gardens and the smoke can be antisocial.

On the other hand, I would always avoid fires generally in the wind. As you have said, sparks can be a consideration. But it also increases the risk that a spark that does go wild will ingnite something and spread quickly through grass or whatever.

I'm not sure why making biochar in particular would be different from other fires, although with the system I use (a trench) i think the yield would be reduced as more oxygen would get to the embers.

I agree that in the rain does reduce risk greatly, or even the day after a rain. I'm just back from a scout campout on a damp weekend. Having a fire was a bit of a challenge but pretty safe. I must admit when I was tempted after dousing the fire Saturday night to collect some of the beautiful char the wet coals made.

Wind, though, increases the risk pretty significantly. I usually won't burn if the tree branches are swaying much. I burn an open fire around a can of biochar-to-be, so if you have a closed system your risk may be lower.

The consideration that more wind means more oxygen is also a good one...it might act like billows on a forge and make the burn go faster than desired, creating more ash.

As a general rule, I trust my gut. If I'm not sure I should be burning on a certain day, I don't burn. There's always tomorrow and it's not worth risking potentially big problems to make char today you can make safely tomorrow.

Since I live in the roaring 40s and my main production method is a kontiki, wind is very much a consideration and I often have to change my plans because of it. Lots of burns get postponed or cut short if the wind picks up. A light breeze is fine, and my smaller (600 litre) vessel has a rim shield that helps keep the flame cap intact. But my 900-litre workhorse doesn't have a guard around it, and it doesn't take much to start shearing off the flames and encourage smoking.

If I do go ahead with a burn on a breezy day, I get a slowing effect on the upwind side of the container, and a hotter fire on the downwind side. I usually compensate for this by putting larger cross section pieces on the "hot" side of the kiln and also by stirring things from time to time.

Weather dependency is the biggest downside of flame cap pyrolysis, in my view. I've tried to get around it by building a drying shed where I can stage enough feedstock to do a burn, even in winter, but this leads to double handling. On top of that, the shed is so practical that I find myself using it for other things, like curing tree hay and bean vines that get pulled in the autumn, so it doesn't just do biochar duty these days.

For open fires, I keep a hose handy and spray any time the fire gets strong. Want a slow fire, and it prevents the fire getting loose! Wet days are better, if possible.

I do think that with lots of wind, it can mess up the oxygen amount that you want in making the char.  I think I will pause or burn earlier in the morning to get less wind next time.

JOhn S
PDX OR

It was windy enough recently that my chimney got knocked over and broke open.  It was a 10" metal tube but then it wasn't a tube any more, like this:

So I decided to buy a riveting tool.  It was very useful in repairing the chimney.  I also was able to attach the chimney to the lid, so it wouldn't keep getting blown over. I wish I would have done this earlier, but that's how you learn.  The rivets are fine after burning:



John S
PDX OR

I do open fire so it's more important to watch out for the wind. In spring time, we typically have gusty Sw wind half of the time, then gusty NW wind the other half. I keep the pile ready and wait for the brief period after the cold front passes when it's cool and calm. The resulting char has better quality and it's safe for everybody.