Moving Bulk Material When Moving From Taproom to Retail
With over 8,000 craft and independent breweries now in the US, and macro brewers attempting to protect their market share, the growth in competing beer brands has exceeded the growth in consumer dollars available to purchase them. Resulting financial pressures, exacerbated by the effects of COVID-19 and the waning novelty of craft beers, have forced many microbreweries to shut down.
However, more retailers now offer craft beers to their customers alongside macro brews, giving savvy microbreweries an opportunity to move into retail sales. The success of these expansions will depend not only on their brew master's talents, but also on management's marketing prowess and ability to ramp up capacity by an order of magnitude with no sacrifice in quality. The process that produced a hundred barrels will require a radical upgrade to produce thousands of barrels, including new methods of moving bulk ingredients to and from each step of the brewing process.
Transferring large volumes of bulk ingredients efficiently
Fortunately for brewers, barley, grain, malt, spices, and sugars are easily stored and shipped in bulk bags — also known as "big bags," Supersack® bags and flexible intermediate bulk containers (FIBCs) — which can hold up to 2 tons (1.8 tonnes) of material. Purchasing ingredients in bulk bags can reduce material costs and, with the proper unloading and conveying equipment, allow controlled dispensing into processing vessels with greater speed, higher accuracy and fewer personnel than manual methods.
It is not always apparent which conveying technology is best suited for growing breweries due to the wide-ranging flow characteristics of ingredients and the tendency of each to pack, cake, smear, agglomerate or to emit dust when put in motion.
Evaluate conveyor options
Here are commonly utilized methods brewers employ to convey dry bulk solid materials:
Pneumatic Conveyors: This method moves materials that are suspended in an air stream within the conveying tube. The air stream is generated by a positive pressure blower upstream of material inlet points, or a vacuum pump at the end of the conveyor. Material is then separated from the airstream at the destination points by a number of methods.
Screw Conveyors: This common conveyor type can refer to either flexible screw conveyors or rigid auger conveyors. These methods employ an electric motor that drives a rotating helical spiral to transport material.
Tubular Cable Conveyors: This design uses low-friction polymer discs attached to a stainless steel cable to slide material through the conveying line. The cable is generally driven by a powered wheel near the discharge end of the system while being kept in proper tension by a floating wheel at the opposite end of the conveyor.
Bucket Elevators: These conveyors consist of a continuous chain or belt circuit, which can be partially or fully enclosed. There are evenly-spaced buckets fastened to the circuit that carry the material. There are two types of bucket elevators: centrifugal, which "dig" into a pile of material; and continuous, which have the material fed into them.
Belt Conveyors: In its most basic configuration, a belt conveyor uses a closed loop belt of flexible thermoplastic material powered by at least two pulleys.
Due to wide performance variations of each conveying system, and of individual ingredients to be conveyed, it is advantageous to work with a conveyor manufacturer that offers several different styles so that an objective comparison can be made.
Pneumatic conveying offers the advantages of being able to move large quantities of material long distances. The routing of the conveying line can be less direct, providing many options when laying out your new process. Another advantage is that these conveyors will evacuate almost all of the material at the end of a batch, leaving the conveyor virtually empty. However, pneumatic conveyors carry the highest initial investment costs and can be more complex than some other conveyor types. This complexity requires maintenance of a greater number of components, such as blowers, filter receivers and material in-feed devices. For optimal results, a proper balance between convey line size and routing, blower size and speed, and material separation design is critical. Hence, a supplier experienced in the design of pneumatic conveying systems is critical.
Screw conveyors are commonly employed by breweries due to their lower cost and relative simplicity. Although both rigid auger conveyors and flexible screw conveyors operate with a similar principle, the types of materials used in the brewing industry are well suited to take advantage of the design advantages inherent to the flexible screw conveyor. Because the flexible design does not use a heavy steel core, internal bearings are not required. The absence of these internal bearings results in not only a reduction in maintenance, but also allows conveyor routing at steeper inclines, preserving precious floor space. Further, as the name implies, the flexible screw conveyor can be curved, increasing options for the brewery layout. It must be noted that these are not the "farm augers" that are used to feed livestock, but are durable industrial-grade conveyors consisting of a stainless steel spiral enclosed inside a polymer tube, driven by an electric motor. Material travels at an incline up the convey line and exits at a point before it can contact motor bearings or seals. The screw is the only moving part contacting material, minimizing maintenance.
Flexible screw conveyors can start and stop under full loads, making them ideal for batching. They readily handle compressible and irregularly shaped materials such as grain. They are fully enclosed, dust-free, easy to clean thoroughly, and can be configured on a caster-mounted frame for in-plant mobility. Care should be taken to specify the proper geometry of the spiral to achieve maximum efficiency. At the conclusion of a conveying cycle, flexible screw conveyors will not completely evacuate material, so they are not well-suited to conveying small amounts of material that must be fully introduced to a batch, such as a pre-weighed flavoring ingredient.
Tubular cable or chain conveyors consist of a convey line circuit, usually either a steel cable or a chain, with polymer discs attached at evenly-spaced intervals. The circuit is enclosed inside a steel tube, thus operating dust- and contamination-free. Two "wheels" are used, one to drive the circuit, and the other to maintain the cable or chain's tension. The material rides at relatively slow linear speeds inside the pockets created by the space between the discs. These conveyors are noted for their gentle handling of the material, a key factor when considering the handling of hops in particular. The convey lines can be routed in multiple directions, and feature a built-in, easy clean-in-place process, which reduces downtime. They can have one inlet and discharge point, or several. From a cost point of view, a tubular cable or chain conveyor will generally fall between the screw conveyor and the pneumatic conveyor. Monitoring disc wear and maintaining proper cable or chain tension are at the top of the list for this class of conveyor.
Bucket elevators are also well-suited for conveying highly fragile products since they essentially carry individual buckets of material, as implied by the name, without imparting any energy or shear directly to the material. They can also move large volumes of material very quickly over short distances and are well-suited for transporting material vertically. However, if control of dust is critical, a fully enclosed design must be specified. Bucket elevators can handle a very wide range of products, including wet or moist materials that may cause problems with the previously mentioned technologies. These advantages do come at a cost however, with bucket elevators using a large number of moving components, which increases cleaning difficulty and maintenance. Individual buckets, drive belts and chains all must be monitored for wear and replacement. Cost can vary widely depending upon the features required, but generally this type of conveyor will exceed the cost of screw and belt conveyors.
Belt conveyors provide a low-operating-cost method of moving material over long or short distances. They can handle a wide range of bulk materials from powders to lumps and can be loaded at almost any point that the belt is accessible. The smooth action causes virtually no product degradation. Side walls on the convey line prevent material waste and the open design allows for visual inspection. Belt conveyors can operate on the horizontal or at an incline, although material slippage may arise if the convey line exceeds a 15° incline. Higher friction belt material and/or some combination with bucket elevators is needed for steep inclines. The open design of these systems makes them less suitable for handling of contamination-sensitive materials or for meeting some regulations for food and beverage processing. Dust is not contained and cleaning the belt can be difficult if conveying moist or sticky materials. Further, sticky materials may cling to the belt on the return side, fouling the pulleys and rollers and ultimately impacting the belt tracking. Belt conveyors provide limited routing options and require careful planning for reliable operation.
Match a bulk bag discharger to your application
Switching from smaller bags, sacks and other handheld packaging to bulk bags means that manual methods of feeding the convey line and/or the brew tank must give way to mechanical equipment.
Bulk bags have revolutionized the way bulk materials are shipped, stored and handled. Made from woven polypropylene fibers with four reinforced bag lifting straps, these bags can be lifted by a forklift or hoist over processing equipment. Their contents can be emptied via a discharge spout at the bottom of the bag. Ideally, some sort of permanent frame should be used to hold the bag in place.
Because of the characteristics of many of the materials used in brewing, these frames should be equipped with additional accessories to completely empty the bag contents. This includes features such as spring-loaded frames that will stretch the bags as they empty and lighten, to minimize residual material in the bag. Coarse grain particles can potentially interlock, impeding their flow into downstream processing equipment. Bag-activating devices are usually effective in agitating the material, dislodging pockets of material and promoting flow.
The dust generated during barley, grain, malt, spice, and sugar processing has been identified as a fine material that, in concentrated amounts, has the ability to cause an explosion when mixed with air in an enclosed space and exposed to an ignition source. Repeated exposure to these fine particles over time can potentially cause respiratory problems for workers. This makes dust containment methods a crucial feature to consider when handling these materials.
Most methods of discharging material from a bulk bag include an intermediate receiving hopper that feeds a conveyor. After the bag has been connected to the receiving hopper and the material begins to flow, the air inside the hopper is displaced. Unless this air passes through a filter, airborne dust particles can escape into the surrounding atmosphere. A dust collector mounted on the discharger frame will contain dust inside the sealed system. In some cases, the dust trapped in the filter media can be returned to the receiving hopper by a pneumatic pulse through the filter. This reduces waste and the time necessary to perform the routine cleaning and sanitation typically required in most beverage processing environments.
Add a manual bag dump station for minor ingredients
Most brews involve a blend of materials. In the event that lesser amounts of material are being added to the mix from smaller bags, a manual bag dump station with dust hood, filtration devices and a pneumatic pulse cleaner is the recommended. A hopper screen above the receiving vessel will help prevent the introduction of foreign objects and protect operators from contact with moving parts, such as agitators or moving conveyor components.
The COVID-19 Pandemic has changed the way most processors of bulk materials operate. Brewers are not immune to these changes as they are, or may soon be, forced to work with reduced staff due to social distancing requirements or financial pressures, increasing the need for semi-automated equipment that can move bulk ingredients at higher rates with fewer personnel, cutting costs while distancing operators from one another.
To achieve proper batching weights automatically, a gain-in-weight or loss-in-weight system can be utilized. Full-service equipment manufacturers can include a programmable controls system that can automate the entire process, including the opening/closing of valves, starting/stopping of mixers, and the running of the conveyor, stopping the later when the accurate ingredient weight is attained. Manual methods are reduced to the need for an operator to attach and detach the bulk bags.
An efficient bulk handling system will take into account the plant layout, existing equipment to be integrated with new equipment, flow characteristics of each material handled, and the volume of each to be delivered or removed from each point of the process.
For objectivity, it is critical to review these requirements with a manufacturer that offers multiple types of bulk handling equipment, allowing side-by-side testing. It is also imperative that the manufacturer offers proven experience solving bulk handling problems in applications like yours.
While initial investment cost is always a concern, it should be weighed against the benefits of ownership. Low-cost, all-purpose equipment may result in downtime, material waste, dusting and potential injury. Bulk material handling equipment manufacturers offer expertise in processing, so first-time purchasers can obtain free advice from experts in the field. Invest the time needed to equip your brewery with a bulk handling system that delivers the highest efficiency, greatest cleanliness, least maintenance and greatest cost effectiveness — advantages of increased importance during the current pandemic or future force majeure events.
Click to enlarge A 21 ft (6.5 m) long Flexicon® flexible screw conveyor moves malted grain from the milling room to the brewing tank at Cervecera Peninsula craft brewery.