What Is Red Cedar’s Ideal Firewood Moisture? (Meter Test)
Red cedar firewood is generally ready for routine indoor burning when its moisture content is 20% or less; about 15–20% is a practical target. To check it, split a representative log and measure the newly exposed interior with a suitable, correctly set wood-moisture meter. Test three to five pieces, not just one, because a dry surface can hide a wet core.
A moisture reading can feel confusing at first, especially when the meter has different wood settings or the manual uses unfamiliar terms. The key is to test the right part of the wood and understand what the percentage means. I focus on the fresh split face because an exposed outer surface may dry faster than the center.
“Red cedar” can refer to different trees. Eastern redcedar is Juniperus virginiana, while western redcedar is Thuja plicata. If your meter offers a cedar setting, use the closest match available and follow its instructions. If you cannot identify the species or the meter lacks a matching setting, treat the reading as an estimate and look for consistent results across several pieces.
Choose and Prepare the Moisture Meter
A wood-moisture meter estimates the water in a piece of wood. Its moisture-content (MC) reading is based on water weight compared with the wood’s oven-dry weight; it is not a measure of air humidity. A suitable meter and a fresh interior test give you a more useful result than judging by appearance alone.
Before testing, check the meter’s instructions. Some meters use pins that enter the wood; others read without pins. Models can differ in settings, required pin depth, pin direction, and temperature correction. Follow the instructions for your specific device rather than assuming all meters work the same way.
Prepare the meter and the test area:
- Choose the closest available cedar or wood-species setting. If the meter has no cedar setting, use its recommended general setting and note the limitation.
- Check the battery and inspect the probe pins or sensor surface for damage or dirt.
- If the wood is cold, follow the meter maker’s temperature-correction guidance. Species and temperature corrections vary by meter.
- Wear gloves and eye protection when splitting wood. Use a suitable splitting tool on stable footing, and keep hands clear of the striking area.
- Select a typical log from the stack, not an unusually small, dry, or weathered piece.
A meter gives an estimate, not a guarantee that every log in the stack has the same moisture. I treat it as a sampling tool: careful setup and several consistent readings make the result more useful.
Test Red Cedar Firewood in the Field
A field test checks the wood’s interior, where moisture can remain after the outside has dried. Split a representative log, then place the meter on the newly exposed face as soon as practical. Use the meter’s specified pin depth and orientation, and keep the test area away from bark, end grain, cracks, and visibly decayed wood.
Follow this sequence:
- Choose a typical piece from the batch and split it safely.
- Test the fresh interior face, following the meter instructions. For a pin meter, insert the pins to the specified depth and direction.
- Take readings at more than one interior location on that piece. Avoid obvious checks, cracks, and decayed spots.
- Repeat the process on at least three to five pieces from different parts of the stack.
- Compare the results. Do not decide the whole batch is ready because one piece gives a low reading.
| Where you test | Useful for judging burn readiness? | Why |
|---|---|---|
| Freshly split interior | Yes | Shows moisture in newly exposed wood, including closer to the core |
| Bark or weathered outer surface | No | The surface may not reflect moisture deeper in the log |
| End grain | No | It is not the recommended test face for this check |
| Crack or visibly decayed area | No | It may not represent sound wood in the piece |
A common testing mistake is to read the outside of a log that has sat in sun or wind. That surface may seem dry while the center remains damp. Splitting first helps reveal this difference. If the inside is wet or the readings vary widely, test more pieces before making a decision.
Interpret Readings and Improve Drying
For routine indoor burning, aim for red cedar at 20% MC or less; roughly 15–20% is a practical range. Readings above 20% mean the wood is not reliably seasoned for that use. A number below 20% is helpful only if it comes from a sound, freshly exposed interior and is supported by other samples.
| Interior readings from sampled pieces | What they suggest | Next step |
|---|---|---|
| Consistently 15–20% or lower | The tested wood meets the common burn-ready target | Use the readings as evidence for the sampled batch, while recognizing that pieces can vary |
| Several readings above 20% | The batch is not yet reliably seasoned for routine indoor burning | Keep drying it, then split and retest |
| One low reading, with other readings higher | Moisture varies across the stack or within pieces | Do not rely on the lowest result; test more pieces |
| Surface seems dry, but fresh interior reads high | The outside dried faster than the core | Continue drying and retest the interior later |
Moisture above the target can reduce heat output and increase smoke and creosote deposition. The meter does not tell you how your stove or fireplace will operate, but it helps you avoid relying on wood that is still too wet. Follow your appliance maker’s instructions for safe use.
To dry wood that tests high, stack it off the ground so air can move around it. Use a top cover that sheds rain while leaving the sides open. A cover that closes off the sides can limit airflow. There is no fixed drying time that guarantees the wood will reach 20% MC or less; conditions and the wood itself vary. Retest the newly split interior rather than relying on how long it has been stacked.
A useful example is a stack with mostly low readings and a few pieces over 20%. The low readings do not cancel out the high ones. Set the wetter pieces aside to dry longer, then test them again before burning. This approach is more reliable than treating the whole stack as uniform.
Maintain and Store the Meter and Firewood
A meter is most useful when its readings are repeatable and its instructions are close at hand. Keep it clean, protect its pins or sensor, and store it as the maker directs. Store firewood so rain can drain away and air can reach the stack; then test again when you are ready to use it.
After testing:
- Wipe the meter clean and check the pins or sensor for damage.
- Store it according to its manual, and remove or replace the battery as the maker recommends.
- Record the meter setting and readings if you are comparing the same stack over time.
- Keep firewood off the ground and cover the top while leaving the sides open.
- Retest a fresh split before burning, especially if the wood has been stored through wet weather.
Do not compare readings from different meters or settings as if they were exact matches. The same wood can produce different estimates if the devices use different correction methods or are set differently. Use one meter consistently when possible, and follow its calibration or check instructions if provided.
Bottom line: A fresh interior reading at or below 20% MC, repeated across several red cedar pieces, is a practical sign that the sampled wood is ready for routine indoor burning. If readings remain higher, dry the wood with airflow and retest.
Frequently Asked Questions
These answers cover the most common questions about checking red cedar firewood with a moisture meter. The central rule is to judge fresh interior wood, use the meter as its maker directs, and sample several pieces. A single low number or a dry-looking surface is not enough to confirm an entire stack is ready.
What moisture level should red cedar firewood be before burning?
Aim for 20% moisture content or less. Around 15–20% is a practical range; readings above 20% suggest the wood needs more drying for routine indoor use.
Is 15% better than 20% for red cedar?
A reading of 15% is below the usual 20% target, but wood does not need to reach 15% to meet that target. Focus on consistent interior readings, not on drying to an unnecessarily low number.
Should I test the bark or the split face?
Test the newly exposed interior of a freshly split piece. Bark and weathered surfaces can be drier than the wood inside and may give a misleading impression.
How many pieces should I test?
Check at least three to five representative pieces from different parts of the stack. Take more than one interior reading where practical, and base your decision on the pattern rather than the lowest result.
Can I test the end of a log?
Do not use the end grain as your readiness test. Split the log and measure the fresh interior face, following your meter’s instructions.
Does a moisture meter measure humidity?
No. A wood meter reports moisture content relative to the wood’s oven-dry weight. It does not report the relative humidity of the air.
Which species setting should I use for red cedar?
Use the closest cedar or species setting your meter provides. Eastern redcedar and western redcedar are different species, so follow the meter maker’s guidance and use the result as an estimate if no exact setting is available.
Why does the outside read dry while the inside reads wet?
The outer layer can dry faster than the center. That is why a fresh split is important: it exposes the interior that a surface-only test can miss.
What should I do if the reading is over 20%?
Give the wood more drying time. Stack it off the ground with airflow, cover the top while leaving the sides open, and retest a newly split interior before burning.
Does a low reading on one piece prove the whole stack is ready?
No. Moisture can vary among pieces and within a log. Confirm the result with several representative samples before treating the batch as ready.
(This article was written by one of our staff writers, Evan Bradley. Visit our Meet the Team page.)
