In this blog post we cover our “Seam Assessment Protocol” which outlines some essential steps a craft brewery can take to make sure their beer is being canned safely & securely.
Essentials of Canning
The preservation of canned products requires hermetically sealed cans. The process of attaching a can end to a can body is called Double Seaming. The Double Seam is a metal to metal seal formed by mechanically interlocking five layers of metal together, 3 layers from the end & 2 layers from the body.
The integrity of a seamed can is most vulnerable at the Double Seam and preventing leakage is imperative. As an example, for food cans with an internal vacuum, the Double Seams can leak and allow micro-organisms to be drawn into the can, potentially leading to Botulism and food poisoning. With Craft Brew and beverage products, a loss of gas or internal pressure due to a Double Seam defect may allow the introduction of air into the can, affect taste and reduce the shelf life of your product.
Recognising seam defects and immediately correcting them protects your can and your product. If you are going to invest a lot of time and effort into making the best possible product, you need to be sure the consumer receives it the way you intended. The only way to ensure this happens is by maintaining Double Seam integrity.
A beverage Double Seam consists of two stages commonly known as First Operation & Second Operation. The Seam should initially be set to a five can per head seam check, and should meet the target dimensions outlined on a seamer specific specification provided by the can & end supplier.
Once the Seam is qualified as meeting the standard stipulated in the seam specification and the line has entered production, the seams should be assessed as detailed below. In addition, a full 1st & 2nd operation Double Seam Target Set should be carried at regular intervals based upon your production volumes.
Regular visual checks for gross defects should be taken during production runs at intervals not exceeding 30 mins. To do this, a single can should be randomly selected from each seaming head and checked for the following defects: – Cutover/Sharp Seams, Skidding, False Seams, Droops/Spurs, indications of Chuck Damage, Knock Down Flanges etc. Any defects should be recorded and corrective action taken.
Additional visual inspections should be taken immediately following a wreck, a seam adjustment or after start-up following a prolonged shutdown or mechanical adjustment. All observations should be recorded & corrective action taken when irregularities are found.
Teardown or Seam Section Checks
Teardown or Seam Section checks allow all the dimensions of a Double Seam, internal & external, to be assessed and maintain the quality of the seam. These checks should be assessed by a qualified person at least once per shift, and ideally at intervals not exceeding 4 hours. The results of these checks should be recorded both on a spreadsheet and in graph form.
Once recorded, the results can be compared to the seam specification supplied by the can & end supplier. Seam specifications provide the information required to set a Double Seam as well as listing Process & Critical Parameters. Process Parameters are a guide to the dimensions required to achieving a satisfactory Double Seam and may be breached without stopping the line providing Critical Parameters are met. Critical Parameters are industry standards that as well as providing ideal target dimensions, have absolute minimums that must not be breached. If the results show any critical parameter is not being met, a five can per head seam check must be taken & the seamer stopped while the results are assessed.
If the average results from the five can per head check confirm Critical Parameters have been breached and the seam is out of control, relevant remedial action should be taken to return the seam to target and a further five can per head check taken & assessed. Once the seam is deemed to be on target & back in control, production may resume with the standard regime of visual and teardown checks continuing.
The most important thing you can do to protect your brand is to put your beer in a quality package. Putting all your focus on making an absolutely wonderful beer but neglecting to ensure a safe, commercial quality Double Seam could render your efforts pointless and harm your business.
To help you to ensure your beer reaches your customers as you intend it to, PSA are able to assist you maintain both your Seamer/Filler and the quality of your Double Seam by carrying out regular machine-specific Seamer Health & Double Seam checks. These detailed checks are also supported by reports, supplying an in-depth summary of Seamer/Filler condition & Seam quality.