Malt Milling
Malt Handling and Storage
There are many aspects to consider in handling malt and a perfect solution isn’t always easy to come by. Malt handling and all that it entails is often times underestimated and often problems arise due to lack of proper planning and consideration. A well-designed malt handling system will increase brewery operation efficiency resulting in a cost savings.
Malt Delivery and Receiving
The brewer has several options of how malt can be delivered, including malt bags, bulk bags/super sacks, or bulk. Immediately upon receipt and before the driver leaves, check that the quantity delivered is equal to the quantity ordered, and properly record any damage that has occurred.
Malt Bags
Malt bags are delivered in 50 pounds (22kg) or 55 pounds (25kg) quantities on pallets that may contain up to 40 bags per pallet.
Bulk Bags/Super Sacks
Bulk bags are another option and typically range from 1,000 to 2,200 pounds (450–1,000kg). They are reusable containers typically made of woven material with straps on each corner for transport by a fork lift.
Bulk Malt
Generally, breweries that produce 2,000 BBL’s annually will opt to receive their malt in bulk. This practice offers significant cost savings as malt suppliers often provide discounts for bulk shipments and may even offer financing options to support silo procurement.
Storage
There are several ways to store malt; the appropriate method depends on the scale of the brewery. For a small craft brewery, malt storage may be in bags whereas in lager breweries malt is often stored in super sacks or a silo for bulk malt storage.
Bags
Keeping the brewing malt DRY is the absolute priority. Malt is hydroscopic, so it will naturally absorb moisture from its surroundings. Keep the brewing malt sacks away from walls or directly on the floor. Install pallet racking if you have the space and are planning to hold large quantities of stock. It is important to keep the air flowing around the sacks. Blocking the airflow can potentially lead to moisture and temperature build-up which, again, is the perfect environment for insects.
Silos
The best way to store large quantities of malt is in a clean, dry, silo. Not only can silos offer significant savings of being able to buy grain in bulk, silos offer other benefits. They allow grain/malt to be stored for longer, the automated systems save a lot of money via man-power, and although silos can be placed inside when needed, they typically free up a lot of floorspace if placed outside. It is a good idea to add sight glasses to visually inspect the grain levels. Although silos are water tight, they are often single-walled vessels that are subject to environmental temperature fluctuations.
Corrugated-Walled Silos. Corrugated bolted silos require assembly; are most often less expensive to purchase and ship then a welded silo; and can be manufactured much larger than a welded silo (Figure 7.2).
Smooth-Walled Silos. The main benefit of smooth-walled silos is they can come manufactured in a single piece. Single-piece, smooth-walled silos are the best solution for brewers, hands-down.
Sizing the Silo. Appropriate sizing is important as a typical truckload is 48,000 lbs. The silo should have a minimum capacity of 60,000 lbs.
Malt Transfer
Malt Weighing
Small amounts of malt can be weighed out on conventional scales, but when hundreds or thousands of kilograms are used, a metering device such as a rotary valve delivers the product to a scale hopper on load cells.
Conveying Systems
There are a number of options available to the brewer for moving malt and grain—pneumatic or mechanical. Each of them has advantages and disadvantages and need to be considered carefully according to budget and the task at hand. It should be noted however, that there are cases where both modes of transfer can be used in a system together.
Pneumatic Conveyors. Pneumatic conveyors use air or a vacuum to move the grain through a pipe. The air is moved by a blower and it drives the grain with it. Pneumatic conveyors can operate at any angle and can negotiate narrower curves than drag conveyors.
Mechanical Conveyors. As an alternative to the pneumatic conveying options out-lined above, mechanical conveying is sometimes also used. A mechanical conveying system uses a mechanical device (such as conveyor belt, flexible screw, bucket elevator) that is in direct contact with the conveyed material. Conversely the previously described pneumatic conveyors utilize gas (typically air) to transfer the suspended material through the convey line. A distinctive difference between the two modes is that pneumatic conveyors have almost no moving parts, resulting in less downtime for cleaning and maintenance than their mechanical counterparts.
Click on the following topics for more information on malt milling.
