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water or organic solvents. In nature it plays a fundamental role in the defence of the tree against fungi, bacteria and infections, basedon theability of the tannins (tannoids) to bind with proteins irreversibly. Hydrogen bonds bind the two particles and cause the protein to precipitate and denature, known as protein precipitation. And that is what it does to haze-active proteins in beer, while also acting as an antioxidant. However, gallotannin is not the easiest clarifier and stabiliser; losses in the brewhouse and at maturation can be between 2% and 3% and it will impact filterability. When applying any clarification or stabilisation product it is important to assess their effectiveness with optimisation trials; this helps to evaluate brewing efficiencies and cost-in-use. ALL CLEAR? These properties have the effect of reducing the initial production of proteins, polyphenols and other precursor materials that subsequently need removing, and in this respect look back to traditional fermentation methods of English brewers. Both the famous Burton Union Sets and Yorkshire Squares, as well as regional variants such as the ‘double drop’, relied on the fermentation process itself to ‘cleanse’ the fermenting wort and so reduce the sediment load in the final finished beer. Though in appearance very different, Union Sets and Yorkshire Squares both relied on the CO 2 created fermentation foam, and the top fermenting character of the yeast, to lift or push dead or surplus yeast and trub out of the main fermentation vessel and into a trough or slate platform from which these waste products could not drain back into the main wort body. So, like today’s clarification products, they worked by minimising or removing a quantity of material at an earlier stage of production, so reducing the workload of its removal at a later stage. Very few breweries use these ‘cleansing’ techniques anymore. Other newer and often combined technologies do the job more effectively. The key is to always optimise their performance against shelf stability. Consider the brewing process from raw materials and milling, to mashing, wort boiling, hopping, cooling, fermentation, and conditioning; the raw materials, hops, yeast and water are in the loading bay and the clarification and stabilisation products along with filtration or centrifugation do the unloading. The result is a colloidally stable beer without clouds, flocks or sediment, whether it’s clear or intentionally hazy. The process is all about creating, managing, removing, and stabilising non-microbiological particles which, excluding yeast, are primarily proteins and polyphenols (tannoids or tannins) which can lead to chill or permanent haze, carbohydrates, and lipids. These particles range from less than 2 microns to greater than 10 in size. The larger the particle, the faster it settles. Its charge (positive or negative) also matters in terms of attraction, complexation (where particles bond together through various forces including hydrophobic, electrostatic, van der Waals forces, and hydrogen bonding) and sedimentation. Colloidal particles can significantly shorten a beer’s shelf life; equally, they influence its appearance. Thus, clarifiers and stabilisers produce beers that have greater shelf stability. The two go hand in hand. Clarification is the removal of colloids via sedimentation, centrifugation and filtration. Clarifying agents in general include finings such Irish Moss (carrageenan) and isinglass, gallotannins and silica sol (silicic acid). Colloidal stabilisation involves adsorption, complexation and hydrolysation to reduce haze active proteins and polyphenols. The main stabilising agents, which can be used singly or in combination with clarifiers, are silica gels and sols, proline-specific endopeptidase enzyme (PEPfix ® ), and PVPP (single use or regenerable). WHAT ARE PARTICLES? 26 | Spring 2024 | ontapmag.co.za