Smoke.

If you have a good flame that reaches the top of the flue, and there is very little or no smoke, then your stove is running properly. When you first start using the Tawi this can seem elusive; however it should be easy to achieve.

First; make sure your wood is really dry. Even slightly damp wood produces steam when it gets hot and that will prevent your stove from igniting the wood gas it burns properly. If you can hear hissing coming from the firebox then you have some damp wood in there!

Fill the wood tray to the top before pushing it into the firebox. A common mistake is placing new wood over the top of the flames. The heat starts to gasify this wood immediately and can produce too much wood gas, making smoke because the air-to-gas mixture is too rich.

It isn’t critical that the burn line is absolutely straight; however if the fire starts to burn along the bottom of the stack too disproportionately, then you have the same problem as above; too much gas is produced, again causing smoke. This is easy to fix; just push the bottom of the stack in until the burn line evens up.

On a blustery day the wind will occasionally blow the wood gas back down the flue, resulting in a cloud of white smoke. Sometimes this is enough to put the fire out. Usually the fire will ignite again by itself, but if not, you will have to relight it. The hotter the flue the greater the up-draft, so this can be more of an issue when the stove is first lit. Pointing the entrance of the firebox into wind will help reduce the problem.

Resist the temptation to push the wood stack too far into the firebox. If you take the burn line beyond the leading edge of the flue, the fire will go out as it becomes starved of oxygen.

If you have tried all these suggestions and you are still getting lots of smoke, give us a call and we will try and resolve it for you!

Poor fire.

If your stove is working properly, you should have flames licking the bottom of the pot holder on the flue.

Damp wood is the biggest reason for a poor flame. All the wood should be dry, but put really dry, small twigs on top of the wood stack. These will burn with a strong flame and help stabilise the fire.

It is really important to start the fire well. Make sure the sticks you have rested on the scraper are burning vigorously before you set them down and add more wood. If you don’t achieve this, the fire just stumbles along, because you never establish a good updraft which will really fan the flames.

Choked with biochar.

The whole idea of the Tawi is to produce biochar. However, we have found that after half an hour or so the area at the base of the flue can become choked with biochar, which slows down the burn. Poke a long stick, or the handle of the scraper, down the chimney and push the biochar into the chamber at the back of the stove; wear a glove! You will find the stove picks up immediately. Of course the collection chamber eventually fills up completely, and then you will have to put the stove out and empty it.

Adjusting the temperature.

We deliberately resisted the temptation to put adjustable air vents on the Tawi as we felt these would add another variable and make the stove harder to master. You can, however, adjust the temperature of the hotplates and flue burner to a certain degree. The further under the front hotplate the burn line is the hotter the flue-top burner. Conversely the closer the burn line is to the end of the wood tray, the hotter the front hotplate. So if you want more heat out of the flue then run the stove with the burn line further in. If you want a hotter front hotplate, and less heat coming out of the flue, keep the burn line closer to the wood tray end.

Getting the most out of the grill.

The grill operates using radiated heat from the underside of the burner. It is hottest directly under the burn line area. If what you are trying to cook is too far away from the underneath of the burner the results can be disappointing. To toast effectively using the grill you want to keep your food as close as possible to the underneath of the front hotplate, without actually allowing your food to touch the metal. A baking tray turned upside-down is a good way to raise the height of the tray you are cooking on.