Kegging lines range from systems so simple that washing, inspecting, and filling of each keg are done by hand, to fully automated systems that require virtually no human attendance. The output of a kegging operation ranges from a single-head machine giving an output of 15 kegs per hour, to multi-head machines with outputs more than 1,000 kegs per hour (see Figure 18.4).
The scope of a kegging operation is typically all-inclusive and can be divided into the following steps:
Beer kegs can only be transported on pallets. For this reason, kegs are depalletized by pushing the kegs together and lifting the layer with pneumatically operated grippers.
After the kegs are de-palletized, they are tested for internal pressure. Kegs that fail inspection are removed from the line for subsequent inspection and repair.
External Keg Washing
Prior to washing the outside of the keg, it is inverted so that the valve is at the bottom. Before the kegs are cleaned and filled, the protective caps are removed from the fittings. The outsides of the kegs are then cleaned by presoaking, and rinsed with a circulating cleaning solution.
Internal Keg Cleaning
The total wash cycle of the inside of the keg consists of a prerinse reusing the final rinse water, a detergent wash for removing biological and inorganic contamination, and a final rinse. The purpose of the final rinse is not for washing but for removing chemical contamination from the previous steps. The next step is to sterilize the inside of the keg with steam.
For either system to be effective, it is imperative to adopt a completely integrated process and packaging philosophy. The flash pasteurization or sterile filtration system, the SVK packaging line, and the SVK must all be treated as a single clean and sterile system to optimize the reduction of spoilage organisms.
Beer Keg Filling
SVKs can be filled in the upright or the inverted position. However, all automatic kegging systems today fill SVKs in the inverted position. The pros and cons of upright and inverted filling are as follow.
1. Upright filling is slower when introducing beer into the SVK via the spear tube, due to the small cross-sectional area of the inner sections of the valve over that of the outer gas valve.
2. Upright filling is more likely to overfill an SVK if an accurate metering or filling by weight system is not used. This condition creates hydraulic pressure in the SVK and can lead to dispensing problems if the hydraulic pressure of the beer is too high when the SVK is first tapped in the bar.
Volumetric versus Fill by Weight Measuring Methods
As mentioned, the correct amount of beer in the keg can either be measured by a metering system or by a "fill by weight" system. The various types of metering systems include turbine, volumetric, magnetic flow, or mass-flow metering. In many counties; however, volumetric measuring methods do not meet fill regulatory requirements and brewers are required to use a "fill by weight" system for measuring the beer.
Keg Cold Storage
Once palletized, the full kegs of beer are transferred either by conveyor or forklift into cold storage and held at approximately 4 or 5ºC to prevent the development of live beer spoilage organisms that might affect the desired flavor and color profile.
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