The Hidden Risk Behind Every Food Package
Every sealed product carries one quiet question: is the seal truly airtight?
For food manufacturers, a single hidden leak can lead to contamination, spoilage, or the recall that everyone wants to avoid.
Most seal failures start small — a speck of residue in the seal area, a drop in sealing pressure, or a bit of film stretched too far. Temperature swings and humidity can weaken materials until oxygen slips in. You don’t see it until it’s too late.
That’s why quality teams rely on a method that answers that question right away — visually and in real time.
That method is the bubble emission test.
What Is the Bubble Emission Test (ASTM D3078)?
The bubble emission test, defined by ASTM D3078, is a simple visual test that shows whether a flexible package is sealed tight.
Here’s how it works: you place the package underwater inside a clear vacuum chamber, pull a light vacuum, and watch.
If bubbles appear, there’s a leak. If no bubbles appear, the seal is intact.
That’s it.
In 30 seconds or less, you can see the truth about your seals.
Because the result is visual, it removes guesswork. Anyone on your team can confirm whether the package passed, no sensors or specialized training required.
(Full ASTM D3078 reference: ASTM.org)
How Bubble Testing Prevents Food Packaging Recalls
Bubble emission testing turns prevention into a routine habit.
Step 1: Pull samples from the production line.
Step 2: Submerge and pressurize the package.
Step 3: Watch the test.
If you see bubbles, you’ve found the leak before the shipment leaves your floor.
If you don’t, you’ve got visual proof that your seal integrity holds.
That single action — done in under a minute — can stop thousands of dollars in losses.
It also provides traceable documentation for regulatory audits and brand protection programs.
When you can literally see that your product is safe, you can ship with confidence.
Bubble Testing vs Other Leak Detection Methods
Each method serves a different purpose. Bubble emission testing is often the fastest and most intuitive choice for routine QA.
| Test Method | How It Works | When to Use It | Sensitivity | Time/Cost |
| Bubble Emission (ASTM D3078) | Submerge → Vacuum → Observe for bubbles | Flexible food packaging | High | ~30 sec per test / Low cost |
| Dry Chamber | Place the package in a dry vacuum chamber, observe for leaks. | Liquid or high-barrier packs | Medium | ~30 sec per test / Low cost |
| Altitude Simulation | Recreates pressure changes in transport | Products shipped by air | Medium | Moderate time & cost |
| Internal Pressurization (ASTM F2096) | Pressurizes package from inside to reveal leaks | Pharma or medical seals | High | Variable |
Q: When is bubble emission testing best?
A: When you need quick, visible confirmation on flexible food packaging and want to know exactly where a leak starts.
Food Packaging Types That Benefit Most
Meat & Seafood
Prevents contamination before shipment by catching seal defects that compromise freshness and safety.
Dairy
Confirms that pouches and bottles hold tight seals without damaging the sample.
Snacks & Packaged Goods
Identifies weak seams that cause stale or soft product on the shelf.
Pet Food
Prevents odor or moisture leaks that shorten shelf life and harm brand trust.
Next Step: See which FlexPak setup fits your packaging line.
How to Run a Bubble Emission Test in 3 Simple Steps
Step 1: Submerge the package.
Fill the clear chamber with clean water at room temperature and fully immerse the package.
Step 2: Apply vacuum (ASTM D3078 standard).
Pull the chamber pressure down gradually to the test level and hold steady.
Step 3: Observe the package.
Watch for any stream of bubbles.
- No bubbles: Seal is intact.
- Bubbles: Leak detected — note the spot for corrective action.
What success looks like: Clear water, stable vacuum, zero bubbles.
That’s a pass.
Common Mistakes That Skew Results
Over-pressurizing the chamber
Too much vacuum can distort the sample or the chamber window. Stay within ASTM pressure limits.
Skipping vacuum stabilization
Testing immediately after sealing can trap internal air that hides leaks. Let packages rest before testing.
Uneven submersion
Air pockets or contact with the chamber wall can create false bubbles. Make sure the package is fully suspended and visible.
Inconsistent dwell time
Hold the vacuum for at least 30 seconds. Short tests miss slow leaks; longer holds improve accuracy.
By standardizing these parameters, you get repeatable results shift after shift.
Turning Visual Proof into Quality Confidence
You can’t argue with what you see.
When QA teams capture photos or short videos of bubble tests, those visuals become direct proof of seal integrity. They can be attached to batch records, shown during audits, or shared with co-packers.
Digital quality systems make it easy to log each test automatically. Combining video or image evidence with test data provides traceable accountability — proof that every shipment left your facility verified and safe.
This visual transparency not only satisfies auditors but also strengthens your reputation with every client who asks, “How do you know your packaging is airtight?”
Choosing the Right FlexPak Setup
Not all packaging lines look the same. The right chamber size and configuration depend on your products and throughput.
- Chamber Size: The chamber size depends on your largest package, and how many of them you’d like to test at a time. Larger units let you test multiple samples at once.
- Attachments: Add VAC Attachment for vacuum-sealed packs or our Stick-Pack fixture for narrow sachets.
- Automation: Multi-chamber setups allow continuous testing alongside production.
- Support: FlexPak’s 24-hour response keeps downtime low and calibration on schedule.
Q: How do you pick the best setup?
A: Measure your largest package, estimate daily testing volume, and send that info to our team.
You’ll have a detailed quote and configuration within 24 hours.
Final Takeaway: 30 Seconds to Protect Your Brand
Speed. Visibility. Confidence.
That’s what the bubble emission test delivers — clear visual proof that your food packaging seals are holding strong.
In less than a minute, you can:
- Spot leaks before they leave the plant.
- Document results for compliance.
- Keep your brand safe from costly recalls.
Bubble emission testing gives you visual assurance that prevents recalls before they happen.
Ready to add that assurance to your line?
Chat to an Expert