Lesson 2 - Malt Intake, Handling, and Storage
This lesson details the principles and operations of malt intake, handling, and storage. It explains how and why malt is checked on delivery to the brewery. It also covers how it is taken in, processed, and stored, as well as how safety is maintained during malt handling.
Malt Handling Process Overview
The malt handling process takes the malt as delivered and transforms it into malt that can be successfully stored and milled.
The outcome of this process should be grain that is:
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free from foreign material;
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of the correct size profile for milling;
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at the correct moisture level for storage or milling; and
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free from infestation with mould and pests.
Bulk deliveries are typically emptied into a pit or a hopper. This must be designed to prevent water entry and secured against water and pest ingress when not in use. The intake point slopes steeply towards a conveyor or elevator at its base into which the malt slides. The malt is then transported to the silos via various forms of malt cleaning equipment.
All systems feature an inline magnet over which the malt flows in a thin layer. This allows the magnet to catch any ferrous (containing iron) metal which may be present in the grains. If not removed, ferrous material can cause damage to the grain handling and milling equipment. If it passes through the mill, it may also cause a metallic flavour taint in the finished beer and reduce its flavour stability. After this, further foreign material removal can be undertaken using screening equipment and destoners. Screening equipment separates foreign material on the basis of size, removing material that is larger or smaller than the required size of malt kernel. Destoners remove material on the basis of density. Anything with a higher density than a malt grain will be rejected.
The malt will be weighed by an inline weigher before and/or after storage.
A dust aspiration system continuously removes dust from the entire malt handling system. This aspiration maintains a negative pressure throughout the system, ensuring that dust cannot leak into the brewery. The dust is transported to cyclones and filters for removal. Waste dust can either be combined with spent grains, sent for anaerobic digestion/composting, or disposed of.
We will now outline the key features of each of the malt handling and storage technologies, starting with bucket elevators.