Canning Beer
Canning Process
The process of canning beer begins with empty, aluminum blank cans without tops. Cans are automatically fed on to a conveyor belt and first rinsed with pure water to clean the inside. They are then purged with air with carbon dioxide into the empty vessels. The cans then proceed down the line and are filled with beer. After filling, lids are automatically placed on top of the passing can. As the lid drops, a simultaneous burst of carbon dioxide pushes the last bit of air out from under the lid.
Depalletizing
Depending on the type of machine the line has and the brewer’s production demand, depalletizing can be done manually or automatically. For manual and semi-automatic canners, the operator needs to feed the cans into the start of the line by hand. For automatic machines with high production capacities, the operator needs to use a depalletizer to supply bulk amounts of empty cans into a conveyor (Figure 18.3). An automatic depalletizer reverses the action of the can plant’s palletizer, sweeping off one layer of cans at a time, feeding them into the empty-can conveying system.
Pre-Rinsing
Pre-rinsing involves cleaning the cans when they go from the pallet to the filler. This is done to remove any debris that might have fallen into the can between the time of unloading the pallet into the depalletizer and prior to entering the filler.
Filling
The filling technology used for canning depends on the production output and the budgetary restrictions. Rotary filling machines tend to be more expensive, but also more efficient (and higher volume). Rotary filling machines are continuous systems. On the other hand, linear filling machines are on-off systems and thus discontinuous, which means they have a lower production volume.
Foam
When foam hits the sensor and stops the fill, the heads then start to withdraw from the can. The top up valve and top up timer are set up to reopen the fill valves as they withdraw from the can. This replaces the displaced volume from the tubes in the can and also creates turbulence because now it is adding beer as it is coming up and thus creating foam. As the can is leaving the fill area, it should be slightly foaming up over the top of the can and actively foaming until a lid is placed on top of it.
Lid Placement
After the can is filled, an end or lid is placed over it prior to seaming (Figure 18.7). The basic lid dispenser takes one lid at a time off a stack of lids. However, the can lid is convex, and if dropped directly onto a filled can, it will trap air in the convex space, which will lead to high air pickup in the sealed container.
Closure Testing
The accuracy of each of the seaming operations should be regularly evaluated. The thickness of the seam after the first and second operations is specified by the can manufacturer.
Post Rinsing
Filled cans must be rinsed after the fill to remove any beer present. In order to avoid corrosion weakening of the tab opening, it is advisable to warm the cans past their dew point using a can warmer or to at least allow for adequate ventilation in the final package so condensation can dissipate.
Labelling
The brewer has two options when labeling beer cans. The brewer can either purchase the printed beer cans from the manufacturer or label the blank cans after packaging.
Dry End Packing
There are many different options for the final package. Cans may be packed loose into cases or trays or grouped into four- or six-packs and then packed into cases, half cases, or trays.
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