Firewood: the most important rule? It must be DRY!

When we buy a car, we know very well that the fuel matters. We may have the best engine in the world, but if we fuel it with poor-quality fuel, we cannot expect it to perform at its best.

With a wood-burning stove or fireplace, exactly the same principle applies.

We may have a modern, efficient appliance, perfectly installed and connected to a professionally constructed flue, but one thing remains fundamental:

we need to provide it with good fuel.

And in the case of firewood, even before discussing whether beech, oak, acacia, ash, or fir is better, there is one characteristic that matters more than all the others:

FIREWOOD MUST BE DRY.

This is the true golden rule.

How dry should firewood be?

Here, it is important to clarify a concept that often causes confusion.

Wood naturally contains water and it is not necessary to reach 0% moisture (which, under normal environmental conditions, would in any case be unrealistic)

To be considered suitable for combustion, firewood should have moisture below 15%. The lower we can get it, for example toward 10%, the more easily we will achieve quick lighting and lively combustion. The EPA also indicates a moisture content below 15% as a benchmark for good combustion.

Why is this so important? For a very simple reason:

water does not burn.

When we put wet wood in the firebox, some of the energy produced by the fire is used to heat and evaporate the water contained in the wood instead of producing useful heat.

The result?

Wet wood generally means:

• greater difficulty lighting;
• lower combustion temperature;
• more smoke;
• glass that tends to get dirty more quickly;
• more deposits in the firebox and flue system;
• less useful heat;
• less efficient and more polluting combustion.

The Veneto Region’s guidelines on biomass use recommend wood with a moisture content below 15%, explaining that excess moisture reduces heating value and makes it more difficult to reach high temperatures in the combustion chamber.

In other words: before blaming the stove, fireplace, or chimney, let’s check the firewood!

So, what is the best firewood to burn?

Here, we can have a little fun going into more detail.

Different wood species have different characteristics, especially when compared by volume.

Denser woods, such as beech, oak, black locust/acacia, and ash, generally contain more energy in the same volume than lighter woods. However, at the same weight and moisture content, the energy differences between the various species become much less significant than is often believed.

In practice, we can distinguish them as follows, to simplify:

Beech
One of the great classics of firewood. Good heat output, a beautiful burn, a good flame and good embers. It is a very versatile and pleasant wood to use.

English oak and oak
Hard, dense woods, excellent for maintaining the fire and producing long-lasting embers. They are particularly useful when we want a longer burn.

Black locust, commonly called acacia
It is a very dense and tough wood. Once combustion is properly established, it is particularly useful for maintaining heat and embers for a long time.

Ash
Another excellent firewood, with good heat output and steady combustion.

Birch
It lights easily and produces a beautiful flame. It can also be very pleasant in fireplaces where the visual aspect of the fire is important.

Fir and other conifers
They are lighter woods and tend to burn quickly, producing a lively flame. This characteristic can make them particularly useful during the lighting phase, provided, of course, that they are thoroughly dry and used according to the appliance manufacturer's instructions.

But be careful not to turn all this into an extremely complicated science.

There is no need to drive yourself crazy!

Sometimes it almost seems that lighting a wood-burning stove requires a degree in forestry.

“That one is no good because it is too light.”

“That one is fine, but only after three years.”

“That one produces too much flame.”

“That one produces too much embers.”

“That one is only suitable at 6:37 p.m. with a north-easterly wind…”

Stay calm!

The characteristics of different types of wood exist and are useful to know, but in real life a good wood-burning stove or fireplace can work perfectly well with many different types of wood.

If we have beech available, fine.

If we have oak, fine.

If we have ash, fine.

If we have acacia, fine.

If we have a mix of different types of wood, excellent.

The fundamental thing is that it is virgin wood, suitable for combustion and, above all, DRY.

Between wood considered “premium” but damp and more common wood that is perfectly dry, for us there is no doubt:

choose the dry one.

A little trick for a good fire-lighting

If we want to improve combustion further, we can use different types and sizes of wood at different stages.

When lighting the fire, we want to achieve a good flame and a high temperature quickly.

The aim is not merely to light the logs.

We need to heat the firebox quickly and, above all, the flue: by increasing the temperature of the smoke, we help activate the natural draft.

For this reason, it is very useful to start with dry wood split into small pieces, together with a suitable firelighter.

We can use, for example, thin pieces of beech or lightweight, very dry woods such as fir, provided they are compatible with the manufacturer's instructions.

Once the fire is well established, the firebox is hot, and the flue has begun to draw properly, we can move on to larger logs and denser woods.

For example, acacia/black locust, oak, or other hardwoods can help us achieve a longer burn and longer-lasting embers.

The EPA also recommends starting with a small, hot fire using dry kindling, gradually adding larger pieces and leaving enough space for air to pass through.

It is a very simple principle:

small and lively to get started, larger and longer-lasting once the fire is going.

How can I tell whether my firewood is truly dry?

The best method is very simple: measure it.

There are small wood moisture meters that cost relatively little and provide a very useful indication in just a few seconds.

One tip: to obtain a meaningful measurement, split a log and measure the moisture content on the freshly exposed inner surface, not simply on the outside of the piece.

The outside may in fact appear perfectly dry while the heart of the log still contains a lot of water.

As a reference, let’s remember once again:

below 20% = minimum result for combustion

around 10-15% = dry firewood and generally excellent to use

There is no need to aim for 0%.

It simply requires well-seasoned, dry firewood.

Buy firewood or prepare it ourselves?

Both solutions are perfectly fine.

We can buy firewood from a trusted supplier, asking for firewood that is already seasoned and ready to use.

Alternatively, we can buy or prepare fresher firewood and let it season ourselves.

In this second case, however, it needs time and, above all, air.

The timing can vary greatly depending on the species, the size of the pieces, the climate, the exposure, and how it is stacked. As a general guideline, the EPA recommends at least about six months for softwoods and at least one year for many hardwoods; in other conditions, even more time may be necessary.

So let’s not rely solely on the calendar.

We measure the moisture content.

It is the simplest way to know what we are actually putting in our stove.

And now we come to one of the most common mistakes: where should firewood be stored?

This is probably one of the most important points in the entire article.

And yet it is often underestimated.

SEASONING FIREWOOD SHOULD BE KEPT OUTDOORS.

It seems like a contradiction.

“But outside it absorbs moisture!”

“If it rains sideways, it gets wet!”

“Better put it all inside the garage!”

Not necessarily. In fact.

To properly season firewood, it mainly needs one thing:

AIR.

Water that reaches the sides of the woodpile during occasional rain can dry again fairly quickly.

Much worse is trapping moisture inside the stack and preventing air from circulating.

The EPA's guidelines are very clear: firewood should be stored outdoors, raised off the ground and covered only on top, because closing the sides as well traps moisture.

The Veneto Region also recommends storing firewood intended for seasoning in a place open on at least three sides.

How to stack firewood correctly

The ideal solution is therefore very simple:

OUTDOORS + RAISED OFF THE GROUND + COVERED ABOVE + OPEN ON THE SIDES.

A shelter is perfect.

But a properly made top cover, a panel or a tarp placed only on top, leaving the sides open, may also be sufficient.

The purpose of the top cover is to prevent large quantities of water from continuously penetrating deep into the stack.

We must not turn the pallet into a waterproof gift package!

No tarp wrapped completely around the firewood.

No sealed stack.

No fresh firewood sealed in an unventilated room.

Air must be able to enter from one side, pass through the stack and exit from the other.

It is precisely this continuous exchange of air that allows the moisture present inside the wood to escape gradually.

A stack completely wrapped in a tarp may seem very well protected, but it risks becoming a real moisture trap.

And at that point, instead of seasoning properly, the firewood can develop mold and, in the worst cases, begin to deteriorate.

So let us remember just one thing

We can talk for hours about beech, oak, ash, birch, fir and acacia.

We can compare heat output, density, ember duration and flame beauty.

We can study the ideal piece size and perfect the lighting technique.

All of this is useful information.

But if tomorrow you were to remember just one thing from this article, we would want it to be this:

THE BEST FIREWOOD IS DRY FIREWOOD.

Good dry firewood makes lighting easier, helps the firebox quickly reach the correct temperature, produces less smoke, gets dirty less and allows our stove or fireplace to work much better.

Buy it dry from someone you trust or prepare it yourself.

But if you have to season it, give it time and give it air.

Keep it outdoors, raised off the ground, protect it mainly from above and let the sides breathe.

Because we can have the most beautiful fireplace in the world, the best stove and a perfect chimney...

but in the end, fire can burn well only the fuel we give it.

And with firewood, the golden rule always remains the same:

DRY. DRY. DRY.