Thought I'd post the wood fired boil I did over the weekend. I've seen this question asked a few times but I'm not sure there's been an answer to this extent yet. I've attached a picture, but it was taken before I actually got a boil. In the picture the grates were set up wrong and I was burning the wrong wood at the wrong settings. The grill can handle 2.5 gallons and the setup can probably be scaled up to 5 gallons pretty easy with some basic metalworking skills. I do a lot of barbecuing and have cooked most of my dinners on wood fires this summer, but there was definitely still a learning curve on this one. Like taking almost 2 hours to boil water kind of learning curve, but now I have a new brewing method out of it.
It didn't take a lot for the wheels to start turning on this. Propane is getting more expensive on pretty much every trip to fill up the tank, the yard is filled with seasoned wood, and the pot for partial boils fits on the grill. I learned a lot about boiling water during the 75 minute boil:
Grate size needs to be as small as safely possible. I took almost an hour of trying to get a boil before I realized I was heating up way more metal than was necessary and heat isn't exactly plentiful in this setup.
Hardwoods are essential. I started with sassafras because it's so readily available here and is worthless our wood stove, but couldn't maintain the heat without using hardwoods. I got best results from an oak/wild cherry mix.
Small fires burn cleaner. Using a smaller and hotter fire gives you less smoke, so less smoke goes in the beer. This is where the hardwoods come in, they burn hotter. If you use a hardwood, burn hot, and keep the lid on for most of the boil, a clean tasting lager probably would even be able to be done this way. This batch has a definite oak cask characteristic already because of so much smoke in the beginning of the burn when I didn't have everything set up right, mostly just from too much wood on the fire.
Some type of oxygen control is essential. I'm not sure how this would have ended up if I didn't have a direct way of controlling my flame the same way as a burner. I could lift the tray for the fire to the bottom of the pot to smother it if things got too hot and drop it to allow more air flow, but there's countless ways of controlling the flame.
It didn't take a lot for the wheels to start turning on this. Propane is getting more expensive on pretty much every trip to fill up the tank, the yard is filled with seasoned wood, and the pot for partial boils fits on the grill. I learned a lot about boiling water during the 75 minute boil:
Grate size needs to be as small as safely possible. I took almost an hour of trying to get a boil before I realized I was heating up way more metal than was necessary and heat isn't exactly plentiful in this setup.
Hardwoods are essential. I started with sassafras because it's so readily available here and is worthless our wood stove, but couldn't maintain the heat without using hardwoods. I got best results from an oak/wild cherry mix.
Small fires burn cleaner. Using a smaller and hotter fire gives you less smoke, so less smoke goes in the beer. This is where the hardwoods come in, they burn hotter. If you use a hardwood, burn hot, and keep the lid on for most of the boil, a clean tasting lager probably would even be able to be done this way. This batch has a definite oak cask characteristic already because of so much smoke in the beginning of the burn when I didn't have everything set up right, mostly just from too much wood on the fire.
Some type of oxygen control is essential. I'm not sure how this would have ended up if I didn't have a direct way of controlling my flame the same way as a burner. I could lift the tray for the fire to the bottom of the pot to smother it if things got too hot and drop it to allow more air flow, but there's countless ways of controlling the flame.
