Wine Bottling Operations
The main bottling operations generally include the following: decasing/depalletizing, dedusting or rinsing, bottle filling, corking/capping, labeling, and capsulating or foiling. The bottling line can vary from a manual operation in which several people may be handling hundreds of bottles per hour to an automated line with two to three operators handling several hundred bottles per minute. Some lines are set up in a straight line, with materials flowing from one end to the other, while others have a U-shaped layout with the finished bottles being returned to a point close to where they were first dumped from their cartons.
There are two primary ways to bottle wine today: in-house bottling and mobile bottling. With mobile bottling, a vendor who specializes in the bottling process typically comes onsite to a winery to handle this part of the process (Figure 13.2). Mobile bottlers can handle everything from filtration, bottle cleaning to corking, filling, capsuling, and screw-capping for a winery.
Sanitation of Bottling Line
The bottling line is the last opportunity to control wine spoilage organisms in the winery. Usually, the contamination of wine in this stage results from a lack of an adequate cleaning and sanitation program of the bottling line. Sanitation must be performed immediately before each production batch and after extended shutdown periods to kill most of the microorganisms retained on the equipment (Chapter 15).
The bottles being delivered to the winery are either delivered in reshipper cases or bulk pallet loads. If reshippers, the bottles must be unloaded from the cases to feed the bottling line, using a decaser. Then, the cases are transported to the packer for repacking.
The major bottling components are generally be enclosed in a separate room specially designed for ease of cleaning (e.g., tiled floors and tiled or stainless-steel paneled walls) and sometimes, a sterile atmosphere (positive-pressure, membrane-filtered air).
The wine is moved from the holding tank to the filtration system. Membrane filters are placed just before the filler bowl and are the last physical adjustment to the wine before it enters the bottle. Pre-bottle filtration is accomplished using a series of membrane filters usually beginning with a pore size of 2.0 ?m or 1.2 ?m.
Semi- versus Fully-Automated Bottling Lines
Typically, bottling lines are referred to as semi- or fully automated. A semi-automated bottling line consists of separate mechanized components requiring manual labor to move bottles from one component, or station, to the next. It's labor-intensive, but there is a cost savings. A semi-automatic line operated by three to five workers can reasonably produce 300 to 400 cases per day.
Monoblocks are bottling line systems consisting of multiple pieces of equipment mounted on the same chassis (Figure 13.3). The exact handling of the bottles, and the wine chosen to fill them, determines the configuration of the monoblock. Placing several bottling machines on the same chassis allows the various components to be driven by the same motor.
Mechanical Systems versus Computerized Systems
Bottling lines in general, and monoblocks, are becoming increasingly automated and computer controlled. Mechanical systems are subject to hydraulic shocks caused by opening valves, tanks with a high hydrostatic volume,or just by the stop and go of the filler have an influence on the filling level.
It is common practice with all wineries to purchase new bottles from the manufacturers. The cleaning and sterilizing of used bottles are not practical, neither from a production angle nor from a financial consideration. Bottles purchased are clean and virtually sterile, as they are packed while still hot. In theory they should be ready for filing.
The size of the bottling line determines the number of filler spouts on a filler bowl. Smaller lines have 6 to 12 spouts, whereas larger continuous-flow lines can have 40 to 120 spouts. Bottle filling can be separated into gravity, counter pressure, and vacuum with counter pressure. As the names imply, they employ different forcing conditions prior to and during the filling operation. Gravity feed are the simplest but slowest, whereas counter pressure and vacuum/counter pressure fillers are more appropriate for rapid, automated filling lines.
The fill level of the bottles is critical by legal, winemaking, and economic standards. The Tobacco Tax and Trade Bureau (TTB) requires all 750 ml bottles to be filled with exactly the same amount of wine at 20 degrees C (68°F). Bottle manufacturers provide a table (Figure 13.6) listing how many millimeters are needed for a legal fill at a given wine temperature.
Based upon figures from Principles and Practice of Winemaking by Boulton et al., 1999, the thermal expansion of wine between 20 degrees C (68°F) and 40 degrees C (104°F) is 0.08%.
Fill Height and Ullage Distance
The fill height, or the distance from the surface of the wine to the top of the bottle, with the bottle in an upright position, is generally between 55 and 63 mm for conventional glass wine bottles, with a greater distance used for larger cork lengths greater than 49 mm (Riboulet et al., 1994).
The corking machine takes the filled bottle and positions it beneath the corking plunger (Figure 13.7). The jaws of the corker then radially compress the cork to a diameter that is smaller than the bottle neck. It then pushes the compressed cork into the bottle neck with a single swift plunging movement, so that the top of the cork rests at, or just below, the lip of the bottle. Oversized corks can cause leaks as easily as those that are too narrow.
Screw Cap Machines
Screw cap applications are a little more involved since the headspace volume is bigger than with cork applications. Ideally, we want to remove the air which resides in the headspace. This is done by dosing liquid nitrogen to the headspace of the bottle.
The final operation is to place a plastic cover (or metal foil) over the corked bottle and to shrink this tight by heat (or to spin tighten it) onto the bottle (Figure 13.8).
The traditional labeling operation involves the attachment of a glued front label to the bottle, with options for the attachment of a back label and a neck label as required (Figure 13.9). The continuous labeling machines remove a bottle from the line and during one cycle of its rotation, pick up a label, apply glue to it, place the label onto the bottle, then brush it around the bottle before returning the bottle to the mainline.
Case Packers and Sealers
Once wine bottles have gone through the filling, capping, and labeling processes, they are then packaged in cases. The majority of wineries reuse boxes, called reshippers, the bottles came in. If not using reshippers, a case packer is normally combined with a case erector that builds a fresh box. In this scenario, a case erector will set up and seal the bottom flaps of corrugated cases. The empty boxes are then conveyed from the drop-table to the case packer, all the while with their flaps wide open. Then, the cases travel to a partition inserter that erects and inserts cardboard separators into the case.
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