Fire Basics

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Fire must have three things available in order to sustain itself: oxygen, fuel and heat.

Image from:
Wikipedia

1. Oxygen

Oxygen (O2) exists naturally in our atmosphere at a level of approximately 21% of the air we breathe. With that being said, our atmosphere is not the same in all areas of the Earth and, more importantly for this scenario, is especially different at different altitudes around the globe. In general, the higher you go in altitude the “thinner” the air is. The term thinner simply means that the percentage of available oxygen in the air gets less as you increase your altitude. Taking note of altitude, many times, becomes an issue of concern for those hiking, backpacking or climbing in the mountains for reasons such as breathing and for fire/cooking. The reason for being worried about a lack of O2, when concerned with breathing, is pretty self-explanatory. The less O2 in the air, the less you inhale. The resulting effects can be trip, or even life, ending. For more info on the effects of a lack of O2, or altitude sickness, see websites such as: Healthline, WebMD, or Altitude.Org. The other main concern is fire/cooking. Fire, in general, is used for two purposes: cooking and warmth. With cooking in mind, the effects of altitude are more pressure related than lack of O2 related. Basically, the higher in altitude you go the less pressure there is. This pressure change will affect the boiling point of water. Water that boils at 212°F near sea level will boil at lower temperatures the higher you go up in altitude. In general, the boiling temperature drops 1° per every 500‘gained in elevation.  In backpacker terms, your ramen may be a bit crunchy as compared to how it normally is when prepared in the same manor at or near sea level. Boiling times you are used to will, more than likely, increase; that is unless you don’t mind crunchy ramen. In addition to cooking, there are other concerns with fire and elevation. Fire breathes O2 just as you do. With that being said, fire dies without O2 just as you do. When the air is thin, you may even notice that it is more difficult to get a fire going. Just as you would expect if you lessened the fuel side of the fire triangle or the heat side of the fire triangle, when you lessen the O2 side of the fire triangle an unlit fire struggles to generate and a lit fire struggles to maintain itself. Top

2. Fuel

Fuel, for campfire purposes, generally consists of materials found around the environment that an individual finds him or herself in and will generally consist of natural material such as dry tree material. These materials can be broken down into “types and sizes” necessary to aid in helping a fire begin to generate the heat necessary to sustain itself. These size levels are, from smallest to largest, tinder, kindling and, finally, the fuel itself. Fuel, especially tinder, should be in the back of your mind well before it is needed. Be mindful for supplies while you are on the trail, headed toward the evening’s campsite, especially if you are headed above the tree line. Often times, you pass up a lot of great tinder material along the way. For a quick example, when you find yourself near water, see if there are any cattails you can later use for tinder. In the offseason, grab that bird nest you saw in the bushes as it will make good kindling, and maybe even tinder, material. Tinder can be stored, relatively safe from dampness in items such as a Zip Lock bag, Old 35mm Camera film canister, Prescription medicine bottle, an empty Nalgene or similar.

Tinder Section

Unprocessed Tinder Tinder is the fuel stage that will, fairly easily, ignite with a spark. Tinder is an important step in the beginning stages of both building and starting a campfire, especially if you are going to be attempting to get a campfire started with spark or by creating a coal using a friction method. Some examples of tinder include items such as cotton balls, shredded birch bark or, as pictured above, dry grasses.

Processed Tinder You'd be hard pressed to get the Tinder in the Unprocessed Tinder image above to light with just a spark. Now, if you were to use a flame, from items such as matches or a lighter, you'd surely have no problem. With that being said, your heat source is important to consider when both looking for and processing Tinder. The Tinder above was processed down by simply grinding it over the block that it is sitting on. There are countless ways to achieve this result. Be careful not to depend on any one method to heavily as flexibility and creativity can be key tools to have should you need them.

Kindling Section

Unprocessed Kindling Kindling is the fuel stage that fits directly between the tinder and the fuel itself. It is most anything that is flammable, yet will not take a spark, and goes up to small twig sized branches. Often times you can get many levels of Kindling from one source. Take for instance the Unprocessed Kindling image above.

Breaking down the Unprocessed Kindling first begins with separating all of the different small branches from the main branch itself.

The tiniest of the Kindling will, more than likely, be some of the first Kindling to heat up enough to ignite and transfer the flame from the Tinder to the different stages of Kindling itself. Many light pieces of kindling can be roughed up enough to perform the function as tinder, for example birch bark. In its typical harvested form, it works very well as kindling. Shred it up a bit and it also works well as tinder.

The mid-sized Kindling, being of a larger diameter than the small and smaller than the large, will be the next of the Kindling to light.

The thicker portions of the Kindling are the transition to the Fuel stage.

Tinder Broken Down

Fuel Section

Fuel is the final stage. It will definitely not ignite with a spark and more than likely will not light with a match either as the diameter of the fuel itself is, generally, too large for it to heat up to levels that will sustain the fire triangle; it needs heat help. It gets this help from the kindling that is burning under and around it. Any flammable material, that won’t directly light with a match, can be considered fuel. I'll spare you the agony of looking at stick larger than kindling. ;-) Top

3. Heat 

The tinder, kindling and the fuel is more than likely ambient temperature when it is harvested. This can be quite cold. The larger the diameter of the fuel, the more heat is needed in order to create a self-sustaining fire. Think of a piece of tinder such as a cotton ball. If you look closely, it is made of very small, intertwined, fibers. Consider the diameter of each the individual fibers; they are very small. This is one of the main drivers in its availability to allow the generation and sustainment of a flame with merely a spark. Increase the diameter and you’ll need more than a spark in order to generate and sustain a flame; it is here where you step into the kindling arena. A good pile of well-ventilated tinder should be adequate enough to maintain a flame long enough for the kindling to heat up sufficiently and be able to sustain its own flame.

Processing Fuel

Many larger pieces of fuel can be broken down into kindling and then even further into tinder. For example: Splitting a stick lengthwise can create quite a few pieces of kindling out of one piece of fuel. Taking a similar stick and shaving thin slices off of it can create a middle-ground between tinder and kindling or, with practice, even tinder itself.

Before You Light

Preparation is key. Along with keeping an eye out for tinder along the trail, you also must ensure you have gathered all necessary supplies before you begin attempting to ignite your fire. You must ensure you have enough available tinder, kindling and fuel or you may be wasting a lot of time. Imagine a scenario where you have worked hard to break down fuel into kindling and break that kindling into tinder. Now, imagine you get the tinder to take a spark. It lights up beautifully. You are ready for the kindling and there either is none or not enough to get the fire hot enough to begin to burn the fuel you have, hopefully, set aside. You quickly scramble and start snapping branches and grabbing small flammable items. If you manage to keep the fire going, you are lucky. Depending on luck is a lack of planning and a lack of planning is planning for failure. Tip: Prepack tinder before your trip. It packs down small and is very light.

Fire Lays: A small structure, made from Tinder and Kindling, built with the purpose of igniting Fuel-wood. 

My favorites are the Log Cabin and TeePee fire lays.

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