>>359502Never heard of birch beer but birch wine is made from the sap you get from tapping the trees in late Feb/early March. It's clear and high in sugar. You can reduce it down to make syrup which is good in baking.
Birch tar is made by cooking birch bark or twigs/woodchips ina sealed environment and collecting the run off. It's brownish black like treacle when warm and pretty stiff when cold. Add powdered charcoal to it and it makes a pretty hard glue. A drop or two in a shot of whiskey is a nice addition to marinades.
I don't know much about gasifiers but I think it's a similar method. You're just harnessing the gases released by cooking the wood rather than letting them escape to the atmosphere.
