Avoiding label bubbling on wine bottles can be tricky even under ideal circumstances – and as we all know, circumstances are often far from ideal.
Perhaps you’re using large labels, whose increased surface area makes it more difficult to prevent bubbling and achieve complete adhesion. Maybe you’re applying labels during a rainstorm or a cold snap, and the moisture is literally putting a damper on things. Maybe it’s as simple as imperfect application pressure.
Let’s explore some of the issues involved, and share some tricks of the trade for creating a bottling line environment best suited to full adhesion.
Label Storage before Application
Since bubbling is caused by moisture from the environment, it’s important to store your labels in the proper conditions. Here, a bit of reverse psychology comes into play: Despite moisture being a culprit in bubbling, moisture absorption prior to labelling is good. This is because is preconditions your paper to the conditions it will face during labelling.
So, after removing all packaging and film strapping (which prevents the labelling paper from absorbing moisture), store your labels in a comparably humid environment for at least 24 hours before application. In terms of temperature, keep it around 20°C (68°F).
Applicator Set Up
The key words here are steady and stable: Once the label is dispensed from the peel plate, even and consistent pressure over the full face of the label is critical to ensuring full adhesion to the bottle.
Addressing the Challenge of Wet Bottles
Water acts as a contaminant by compromising the adhesive’s integrity. Here’s a handy checklist when applying pressure-sensitive labels to wet bottles.
- To help prevent condensation on filled bottles, take steps to control air temperature, humidity and fill temperature
- Blow water off the bottle surface by installing air knives just before the labeling head. Let gravity help by blowing the water down the bottle to expose dry glass
- Immediately after condensation is blown off, apply the pressure-sensitive label to dry glass
Rain and high humidity can lead to moisture forming on the bottle surface – a slow build-up that, though often not immediately noticeable, can still contaminate the adhesive. The best way to prevent this is to prevent the air – and the bottles – from getting too cold. Ideally, both air and bottle temperature should be above 5°C (41°F). To help mitigate the problem of moisture, bottle warmers, air blowers and specialized adhesives may be necessary.
Heavy Label Embellishment
Heavy embossing and embellishment can change the physical characteristics of a paper. When this happens, it may alter the label’s tack and adhesion, since the surface contact of the underside of the adhesive-coated label will be reduced. The risk of bubbling is higher than normal around embossed and bottle seam areas, so it’s best for labels to have a minimum 3mm grain-free zone at the edges.