Keeping honeycomb paper working: storage, humidity and shelf life

A honeycomb roll that ran well in March can tear on every pull in August. Often the paper has not changed. The air in your store has.

Honeycomb paper is plain paper, and paper takes up water from damp air. Damp paper goes soft, its cells do not open crisply, and it tears at the slits. Keep rolls wrapped and dry, off the floor and away from doors, use the oldest stock first, and check every delivery on the day it arrives. How long a roll stays good depends far more on your store than on the calendar.

What moisture does to honeycomb paper

Paper is hygroscopic. In simple words, it takes up water from the air around it and gives it back when the air dries.

The Transport Information Service of the German Insurance Association (GDV) covers kraft paper on its page for packing paper. It says packing paper must be protected from all moisture, including rain, condensation and sea water, and it lists storage climate conditions of 65 to 70% relative humidity with a water content of 5 to 9%. It also warns that poor storage can lead to dimensional changes and distortion. In much of India, the monsoon months often run more humid than that. I would put an inexpensive digital hygrometer in the store, read it every morning, and see how your own store compares.

Think of a papad left open in the monsoon. It does not snap any more. It bends.

Damp honeycomb paper behaves the same way, and you see it on the packing table:

1. The cells open unevenly, or not fully. The 2023 kirigami study by Corrigan and others, Strong conformable structure via tension activated kirigami (Communications Materials, May 2023), notes that if a sheet is too soft for its cut pattern, pulling it does not make the walls stand up out of the plane. Damp paper is softer paper.
2. The ends of the slits tear more easily, especially on a quick pull.
3. Opened cells fold flat under the product, so the cushion is thinner than it looks.
4. Roll edges go wavy, and a wavy edge feeds badly through a dispenser.
5. If paper stays damp for long, it can smell musty and grow mould.

Our guide on what honeycomb paper is explains why open, stiff cells are the whole point.

How to store rolls

I would set up a paper store with these seven habits.

1. Keep each roll in the wrapping it came in until the day it goes on the dispenser.
2. Keep pallets off the floor, and keep the floor itself dry. A floor mopped in the morning can still be damp at noon.
3. Leave a gap between the stock and any outside wall or loading door. That is where rain and damp air come in.
4. Stand rolls on their ends unless your supplier says otherwise. The same GDV page warns that rolls stacked on their side can be distorted by the weight of the rolls above them. A roll squashed out of round turns unevenly on a dispenser.
5. Do not stack heavy cartons on top of rolls. A crushed edge tears and opens badly.
6. Keep paper away from oil, dust and chemicals. GDV describes packing paper as a clean cargo that is sensitive to dust, dirt and oil.
7. Treat the sides of a roll with respect. On large paper reels, GDV notes that a cut only 2.5 cm deep can cost as many as 300 layers. Honeycomb rolls are smaller, but the lesson holds. One forklift tine or a careless box cutter into the side of a roll spoils many metres at once.

The monsoon months

For most of India, June to September is the difficult season. During those months, I would change four things:

1. Order smaller lots more often, so less paper waits in the store. Our guide to honeycomb paper consumption shows how to set a reorder point.
2. Open one pallet at a time, and leave the rest fully wrapped.
3. When each shift finishes, put the working roll back in its bag or cover it.
4. Keep the store doors shut when it rains, and do not stage paper near the dock.

We make our paper in Jaipur, which is dry for much of the year. Plenty of buyers store paper in far wetter places, near the coast or in heavy-rain districts. I cannot sell anyone a paper that ignores the monsoon. Nobody can. What we can do is pack it well and tell you plainly how to keep it.

How long does honeycomb paper last?

Paper has no fixed expiry date in the way food does. A dry, clean, wrapped roll stays usable for a long time. A roll kept in a damp corner can be spoiled within one season.

So I would not trust an exact shelf life in months from anyone who has not seen your store, and that includes us.

What you can do is rotate stock properly:

1. Write the receipt date on every pallet or carton when it arrives.
2. Put new stock behind or below the old, so the oldest is always easiest to reach.
3. Once a month, pull a metre from your oldest roll and look at it. If it still opens evenly without tearing, it is fine.

The signs that a roll is past its best are simple: a soft feel, a musty smell, spots, wavy edges, tears on a steady pull, and cells that will not open.

For exporters: containers and transit

We ship our own export orders in containers, so this part is close to home for us.

A sea container is a closed box. As it warms by day and cools by night, moisture inside can condense on the cold steel roof and walls and drip back onto the cargo.

The GDV Container Handbook section on paper gives practical advice for paper cargo. It suggests a non-woven fleece under the container roof to catch dripping sweat, a container floor with a water content no higher than 15%, and a clean container with no residue from the previous cargo.

From our side of the table, as a shipper, I would add these points:

1. Load only dry pallets. A pallet that stood in the rain last week brings that water into the container.
2. Stretch-wrap pallets for dust and splashes, but only when the paper and the pallet are dry. Film keeps water out, and it also keeps any water already inside from escaping.
3. Ask your freight forwarder whether container desiccants make sense for your route and season.
4. Write the lot numbers on the packing list, so a problem at the other end can be traced.

There is one more risk at the destination. If a container lands in a cold country in winter, the rolls inside are cold. Unwrap them in a warm, humid warehouse and water can condense on them. The Container Handbook advises leaving the container standing in the warm environment for two to three days, until the paper rolls have reached the surrounding temperature. Keep the wrapping on until then.

Checks when rolls arrive

I would run these checks on the day the delivery comes in, not when the first roll goes on the dispenser. They work whoever made the paper, us included.

1. Look at the outer wrapping. Note any tears, wet patches or water marks.
2. Look at the ends of the rolls. Check for crushed or dented edges, and for telescoping, where the layers have slid out into a cone.
3. Smell a roll from each pallet. A musty smell means it has been damp for a while.
4. Feel the paper. It should be crisp, not limp.
5. Pull one metre through your dispenser. The cells should open evenly across the width without tearing.
6. Record the lot number and the receipt date. Keep a one-metre piece from each lot in a sealed bag as your reference.
7. Set aside any roll that fails, photograph it, and tell the supplier the same day.

We would rather you reject a damp roll than pack a customer's order in it.

If a delivery from us arrives damp or crushed, photograph it before you unwrap it further, and send us the photos with the lot number. I would much rather hear about it that day than weeks later, when nobody remembers which pallet it was.