Summer is here, bringing longer days, backyard barbecues, vacations, and plenty of heat and humidity. While many of us look forward to the season, those same summertime conditions can have a noticeable effect on paper tubes and cores.
Like wood, paper is a natural fibrous material that responds to changes in its environment. As humidity rises and falls, paper fibers absorb and release moisture, causing slight changes in the dimensions of a tube or core. Most of the time, these changes are temporary—but understanding why they happen can help you store, handle, and use your products more effectively.
Whether your tubes and cores are arriving from a shipment, sitting in a warehouse, or headed straight to production, a little knowledge about summertime humidity can go a long way toward maintaining consistent performance.
Why Does Humidity Matter?
Paper tubes and cores are made from paperboard fibers that naturally absorb and release moisture from the surrounding air.
As humidity increases, those fibers absorb moisture and expand. When humidity drops, they release moisture and contract. It’s the same reason wooden doors tend to stick during the summer, or hardwood floors expand and contract throughout the year.
For the best dimensional stability, paper tubes and cores should be stored and used in an environment close to 73°F and 50% relative humidity whenever possible.
What Happens During the Summer?
Summer often brings warm temperatures and higher humidity levels. As paper tubes and cores absorb moisture from the air, you may notice slight changes in their dimensions.
Depending on the conditions, you may experience:
- Slight increases in core length
- A slightly larger outside diameter (O.D.)
- A slightly smaller inside diameter (I.D.)
In extremely humid conditions, a 10-inch core can grow by as much as 1/16 inch. While these changes are temporary, they can become noticeable in applications where tight tolerances are important.
The Bigger Concern: Moving Between Different Environments
One of the most common summertime challenges isn’t the humidity itself—it’s the sudden change from one environment to another.
For example, tubes and cores stored or transported in very humid conditions may later be placed into a cool, air-conditioned warehouse with much lower humidity. As the paper begins releasing moisture, the dimensions gradually change again.
During this adjustment, cores may become slightly shorter, the outside diameter may decrease slightly, and the inside diameter may become a little larger until the product reaches equilibrium with its new environment.
Simple Storage Practices That Help
You can’t control the weather, but you can control how your tubes and cores are stored once they arrive.
To help maintain consistent performance:
- Store products in a clean, dry, climate-controlled area whenever practical.
- Avoid placing tubes and cores directly beside heating or cooling vents.
- Keep products away from loading dock doors where temperature and humidity fluctuate throughout the day.
- Allow products time to acclimate if they’ve experienced significant environmental changes during shipping.
These simple practices can help minimize dimensional changes and improve consistency during production.
Not Every Core Will React the Same
If your tubes are packaged in cartons or stacked on pallets, you may notice that the products along the outside are affected first. They’re exposed directly to changing air conditions, while the tubes in the middle remain more protected.
That’s one reason environmental changes don’t always affect every core equally.
A Natural Characteristic of Paper
Humidity-related expansion and contraction aren’t unique to paper tubes and cores.
The same thing happens with wood, flooring, bridge structures, and many other materials that respond to changes in temperature and moisture. Paper behaves much the same way because it’s made from natural fibers.
Understanding these characteristics allows you to better plan for seasonal changes and maintain consistent performance throughout the year.
We’re Here to Help
If you have questions about how seasonal humidity may affect your specific application, our team is here to help. Whether you’re selecting the right paper tube, evaluating storage conditions, or troubleshooting a production challenge, we’ll work with you to find the best solution.
Contact Yazoo Mills today to speak with one of our knowledgeable team members or request an instant quote.
