One of the biggest pyro displays one can pull off on a river trip is something called a grease bomb. Using a hot fire, a good amount of bacon grease, and some water, the little (or big) pyromaniac in us all can come out and play.
When executed correctly, the simple ingredients hurl a massive fireball skyward, produce squeals of enjoyment from the peanut gallery, and show your group a safe display of what happens when you show complete disregard for that age old saying of "don't pour water on a grease fire".
**Warning this Instructable involves fire, explosions, bacon grease, and danger. If you'd like to do another project involving copious amounts of bacon grease with a much lower danger factor, check out How to Make Bacon Soap. Grease bombs can be very dangerous and should only be done by experienced bacon grease pyrotechnicians. When done correctly they are a real good time.**
Step 1: Gather Grease
On the river we collect grease from bacon. Trip guests love bacon - so that means that we're usually cooking up POUNDS of the stuff on each trip. Each pound yields about 1/4 to 1/3 of a cup of grease, so collect all the grease you can until you've got about 2 cups worth.
Any fatty meat will produce good grease, so try rendering grease from different sources and see which produces the biggest fireball. (Anyone who can speak to the flammability of different types of animal fats please speak up).
After cooking the bacon, I let the grease cool. Then, I place a coffee filter on top of a non-breakable sealing container and pour the grease through. If your grease has little bits of meat in it, it won't work as well and it will splatter and sputter as you heat it. The coffee filter takes out all of those impurities and results in wonderful amber clear grease.