Kettle fining, the clarification of the wort at boiling Beyond the important commercial aspect of a beer’s visual appearance, the stakes for brewers are the duration and efficiency of the fermentation and clarification process. Beyond the important commercial aspect of a beer’s visual appearance, the stakes for brewers are the duration and efficiency of the fermentation and clarification process. In an increasingly competitive world, with ever-rising production costs, breweries can’t afford not to think about their brewing processes. Contrary to what the English name for the boiling clarification process, “kettle fining”, might suggest, the main benefits of this practice lie in the ability to clarify more effectively during fermentation. This method shortens fermentation and storage times by several days. We’re going to review the use of carrageenans, also known as “kettle fining” or “cooper fining”, in the brewing process. Composition of undesirable particles in brewing wort Beer clarity is compromised by yeast cells and non-microbiological particles (NMP). Yeasts are mainly eliminated by their natural flocculation during fermentation, or later in the process of clarification, centrifugation or filtration, which we’ll cover in another article. The main problem is caused by PNMs: proteins, often associated with polyphenols and other molecules such as lipids, carbohydrates and/or metal ions. Advantages of using kettle finings A word about Stokes’ law Particles settle naturally under the influence of gravity, as described by Stokes’ law, and as you’ve probably already observed. According to this law, the sedimentation rate of a spherical particle is directly proportional to the difference in density between the particle and the liquid medium, to the acceleration due to gravity (hence the usefulness of the centrifuge), and to the square of the particle radius, and inversely proportional to the viscosity of the liquid. So, if the wort or beer is left to rest long enough, it will clarify itself; this is the basis of the lagering process. Here is the formula of this law in the context of brewing: The aim of using “kettle finings” is therefore to increase the particle size (r = radius of the sphere), which is multiplied by the square, massively increasing the speed of sedimentation. Origin and control of particles in the brewing process Non-microbiological particles (NMP) are produced and eliminated at five stages of the brewing process. Understanding how these steps affect particle formation and removal enables the brewer to control the process better to achieve an optimal and consistent level of particles in the beer, leading to a more efficient and consistent clarification process, whether the final product is keg, can or bottle. It is generally accepted that it is best to remove particles at as many stages of the brewing process as possible. This results in a more efficient and consistent process. For unfiltered beer, this practice results in a clearer beer than if all the clarification were left to the post-fermentation stage. For filtered beer, this means less use of consumables, and fewer post-filtration problems. Origin of “kettle fining” aka must clarification agents Must clarifiers have been used for many years, with raw materials mainly derived from red seaweed, generally of the Chondrus crispus genus. Until the 1960s, Irish Moss was the main material used, and is still used today in a small number of breweries. In the 1960s, developments refined the source of seaweed, and clarifying agents as we know them were produced. Initially, these materials were rather limited in their refinements, but showed a significant performance advantage over raw Irish Moss. In the 1980s, a major breakthrough was achieved with pure, refined carrageenans. These materials are totally water-soluble and highly active. The new, and still current, phase of clarifying agents is the use of granular materials from a different algae source. The new materials are semi-refined algae of the Eucheuma genus. These are the products we offer under the Protafloc brand from Murphy & Sons. Action of Protafloc, our must clarification agent Protafloc contains large, negatively-charged polysaccharides called kappa-carrageenans, which bind to the positively-charged proteins in the cold break as it forms. The resulting particles are relatively larger and settle, falling more rapidly to the bottom of the fermenter. The addition is simple and easy, carried out ten minutes before the end of boiling. Factors influencing the performance of must clarifiers Several factors have been identified as influencing the performance of must clarifiers: arity while minimizing sediment volume. Too high or too low a dosage will be less effective, or even have a negative effect. We can help you determine the optimum dosage. These factors show the importance of understanding and controlling brewing conditions to optimize the effectiveness of clarifying agents and ensure the quality of the final product. We will be happy to provide you with any information you may require on kettle finings and their use. Don’t hesitate to contact us. We offer Swiss professional breweries the resources and expertise they need to improve their brewing processes. Contact us, no obligation Ref1: Effects of Wort Clarifying by using Carrageenan on Diatomaceous Earth Dosage for Beer Filtration by Aleksander Poreda, Marek Zdaniewicz, Monika Sterczyńska, Marek Jakubowski and Czesław Puchalski.
