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Beer Finings

The visual appeal of what we eat and drink significantly affects the consumer’s mind. For most consumers, a bright, clear liquid is preferable to a cloudy one. In recent years, there has been a movement among some craft brewers to promote cloudy or less bright beers. With arguments that the flavour, for whatever reason, is somehow better. However, since many of these brewers do not understand the practical application of finings or do not possess the technology for filtration, their disdain for beer clarity would appear to be very convenient.

The vast majority of beer sold is bright and clear, and its clarity is considered an extremely important attribute.

To produce a bright cask-conditioned beer, the brewer is dependent on the use of finings for clarification. The production of brewery-conditioned beer is less dependent on finings. However, many brewers use kettle finings, isinglass finings, and sometimes auxiliary finings for pre-filtration clarification. Even where brewers have turned their back on using isinglass finings in favour of centrifugation, etc., as pre-filtration treatments, most continue using kettle finings.

To achieve the best fining results, it is important to consider the whole system. From the choice of raw materials to the design and operation of brewing equipment, along with the choice of finings and the dose rate and dose method. Furthermore, it has been shown that optimising clarity at each stage in the process will considerably help produce the most consistent and best clarity at the least cost.

The exact mechanisms of wort and beer clarification are still not fully understood. This is undoubtedly due to the complex nature of wort and beer chemistry. However, sufficient critical factors are well understood enough to allow better use of finings than was the case even as recently as thirty years ago.

If you are interested in purchasing finings, we have an extensive portfolio of products on the Geterbrewed websites suitable for both commercial brewers and the homebrew community. 

Discussion

The pre-history of finings is inevitably pure conjecture. Still, it is possibly easier to see how Irish moss found its way into beer or wort than to imagine how acidified fish swim bladder found its way into beer. The monks who constituted most of the scientific community of medieval times reputedly used Irish moss to clarify wine, beer and honey. At some point, fish swim bladders must have been subjected to the correct set of circumstances, which revealed its clarification potential.

Kettle finings

Historically, kettle finings were flakes of a particular seaweed, Irish Moss, and Chondrus crispus. However, most kettle finings today are produced from Eucheuma cottonii – primarily grown in warmer countries such as the Philippines. The active compound is the polysaccharide kappa carrageenan. It is manufactured in granular, powder or tablet form, the tablets having about 40% active ingredient with the rest binding and effervescing agents.

As recently as the 1920s, kettle finings were described as removing “protein bodies” and considered auxiliary finings for beer. (Harman et al. 1927:203). More recently, by the 1980s, it was suggested “that carrageenans stimulate the precipitation of solids both in the hot and cold wort”.(Mathews 1986: 384). Kettle finings were reported to be responsible for the coagulation of fine particles into larger particles or flocs, which then readily sediment, as well as the reduction in the level of wort proteins (ibid). The reaction between kettle finings and soluble proteins and between kettle finings and non-microbiological particles to create flocs were reported by (Vernon 1984:25),(Montgomery 1986). McMurrough (McMurrough 1985:93) indicates that kettle finings react with the proteins most likely to be involved with chill haze formation. Two papers examining firstly the molecular basis of wort clarification (Dale 1995:285) and looking at the mechanism of action of kettle finings (Dale 1996: 285) confirmed that kettle finings reacted with soluble polypeptides and with non-microbiological particles to create flocs. They also put forward the importance of the change in carrageenan to a helical structure on cooling to enable reaction with these particles.

The importance of kettle finings as part of a complete fining pre-filtration system was now beginning to make better sense. There was confirmation that removing hot and cold breaks at the relevant stage of the process was essential to the later successful filtration and beer stability. Producing a well-coordinated finings system requires the optimisation of each stage. Currently, the practical way of predicting the optimal choice and addition rate of kettle finings is to conduct a series of tests on samples of wort, with the brightest supernatant and the lowest level of sediment indicating the optimal result (Thompson 1994). However, there is hope for a more general predictive test with some work carried out by (South 1996).

Beer finings

Many of the early published papers on isinglass focus on the manufacture of isinglass from fish swim bladders. The importance of the choice and quality of the swim bladders is discussed (Berry 1907) along with the choice of cutting acid or acids, the time to cut, temperature control and the mechanical mixing (Burns 1944). This process was fraught with problems and pitfalls for the unwary brewer, who would quickly end up with substandard isinglass, inevitably leading to poor beer clarity. The advent of isinglass floc and shred considerably improved the brewer’s chances of successful isinglass manufacture with a more rapid and even cutting process. The different fining ability of isinglass made from swim bladders from different sources was correlated with differences in the molecular size of some of the constituent collagen molecules (Leach 1967) and that longer molecules produced better fining results (Leach and Barrett 1967). The positive charge on isinglass attracted to the negative charge on the cell wall of yeast is set forward as the principal reaction of isinglass in beer, as reported by (Wiles 1951: 84), which also explains the inability of isinglass to fine wild yeast. This same principal reaction is confirmed by (Vickers 1974: 19) and by (Taylor1993: 202).

However, there is a more recent hypothesis that the “soluble collagen reacting with a soluble beer component to form loose, fluffy flocs which, as they form, first enmesh and then interact with yeast and non-biological particles to form tighter dense flocs which sediment to leave bright beer” (Leather 1994:432). This would help to explain why the same isinglass addition rate for a specific beer remains the same despite the yeast count varying from 0.5 to 2.0 million cells per ml. The levels of fine particles in beer have been shown to affect sediment volume and beer clarity considerably. When these non-biological particles have been categorised into three fractions, namely below 2 microns, 2 to 10 microns and above 10 microns, it has been shown that the optimum fining performance is obtained when all three categories contain about one million particles per ml. If the beer contains too few particles, while good initial clarity is obtained, the sediment is loose, and if disturbed, the resettlement clarity is not as good. If the beer contains too many fine particles, a greater volume of sediment is produced, and initial clarity is poorer. Any improvement is only possible with auxiliary finings (ibid). Empirical trials are the only way to identify which particular isinglass blend to use and which auxiliary to use, if an auxiliary is required, and what the optimum dose rates are. This involves a series of tests on the beer and a visual determination of the clarity and sediment (Thompson 1994:474). Adding isinglass to beer is of considerable importance to achieving the optimum result.

However, a compromise favouring a simple system rather than a better, more complicated addition system is usually the practical solution. Adding finings to chill and filter beer should be done proportionately to the beer flow during transfer. The finings should be diluted to as low a viscosity as is practicable, and the point of addition should be at a point of turbulent flow. The same procedure is preferable for addition to the cask by adding isinglass proportionately to the beer passing to the cask. However, the typical compromise is to fill the cask, leaving enough space for the isinglass and then squirt the isinglass into the beer-filled cask. This improvement in performance due to the rapid and complete dispersal of isinglass in beer to achieve the best possible result further confirms that the initial reaction of isinglass in beer is more likely to be with a rapidly reacting soluble component than with the yeast cell wall (ibid).

Auxiliary finings appear to react with and remove positively charged soluble material, which would otherwise compete with isinglass or react directly with isinglass itself to initiate the formation of flocs necessary for fining action. Polysaccharide and silicate auxiliaries react differently in beer, so it is likely that both mechanisms apply (Leather 1994:432), and as observed, this would vary from beer to beer.

There is general agreement that a coordinated approach to fining is required to obtain the optimum result for both cask beer and pre-filtration treatment of chilled and filtered beer. This approach is well presented in both (Leather 1998) in the 1996 Cambridge prize lecture and the Brewers Supply Group (BSG) “Wort and Beer Clarification Manual” written by Ian L Ward. While there has been some further progress towards understanding the mechanism of kettle finings (Dale 1995), (Dale 1996), the BSG manual and the aforementioned 1996 Cambridge Prize Lecture contain the most comprehensive presentation of how finings work and how they should be applied. It should be noted that the BSG manual relies heavily on previous research and the methodology employed by Savilles Clarification. This is embodied in the statement:

It has been demonstrated empirically, and has generally been accepted as best practice, to remove particulates at as many stages of the brewing process as practical, since this gives a more efficient and consistent process. In the case of cask beer, considerably brighter beer is obtained using this principle than if all the clarification is left to the post-fermentation stage. For filtered beer, both longer filter runs and lower post filtration hazes are obtained.

Ward, 2014

Moreover, it is borne out by several observations, including, for example, the inclusion of Leather’s observation of the mechanism of kettle finings whereby the carrageenan in kettle finings can react with both soluble proteins and insoluble proteins in separate reactions, in the latter case leading directly to flocculation and in the former leading to first a soluble carrageenan-protein complex and then an insoluble carrageenan-protein complex. Furthermore, Ward explicitly recognises the derivation of these ideas from Leather’s Cambridge Prize Lecture.

The whole concept of finings is under severe attack after hundreds of years of service to the brewing industry. Concern has been raised at the possible allergic reaction to any remaining traces of fish collagen in beer treated by isinglass. Vegan vegetarians who have a thunderous voice for such a small group have managed to persuade Diageo, the owners of the Guinness brand, to stop using isinglass and instead use centrifugation. There is no mention of how much more expensive this treatment will be in monetary and energy terms. Once brewers stop using products like isinglass, the likelihood is that they will never restart, and yet another part of the tradition of British and Irish brewing will have been lost. It will be interesting to see if the use of isinglass persists elsewhere. In a recent paper on filtration choices (Boulton and Quain 2008), there was no mention of any finings as a pre-filtration treatment, and the only pre-filtration treatment recommended for consideration was tannic acid.

Conclusion

After many hundreds of years of successful use of seaweed extract as kettle finings and isinglass as beer finings, the mechanisms of these agents and how beer chemistry interacts with them are more clearly understood. There are still many aspects which need further investigation. Still, for now, the knowledge available supporting finings means that brewers using them can be confident of a reliably successful and low-cost clarification system.

Bibliography

  • Barrett J, Leach AA (1967) The molecular weight and soluble collagen content of finings in relation to its fining potential. J. Inst. Brew. 73: 246-254
  • Berry AE (1907) The Manufacture of Brewers’ Finings. J. Inst. Brew. 13: 44-65
  • Boulton C, Quain D (2008) Making Choices. Brewers Guardian, May: 24-28
  • Burns JA (1944) II The fining of beer. J. Inst. Brew. 50: 119-123
  • Dale CJ, Morris LO, Lyddiatt A, Leather RV (1995) Studies on the molecular basis of wort clarification by copper fining agents (kappa carrageenan). J. Inst. Brew. 101: 285-288
  • Dale CJ, Tran HTN, Lyddiatt A, Leather RV (1996) Studies on the mechanism of action of copper fining agents (K carrageenan) J. Inst. Brew. 102: 285-289
  • Grimmett CM (1994) The Theory and Practice of Beer Clarification – Part 3. The Brewer, December: 522 – 524
  • Harman HW, Oliver JH, Woodhouse P. (1927) Finings, J. Inst. Brew. 34: 203-213
  • Leather RV (1994) The Theory and Practice of Beer Clarification – Part 1 – Theory. The Brewer. October: 429-433
  • Leather RV, Ward IL, Dale CJ (1995) The effect of wort pH on copper fining performance. J. Inst. Brew. 101:187-190
  • Leather RV, Dali CJ, Morson BT (1997) Characterisation of beer particle charges and the role of particle charge in beer processing. J. Inst. Brew. 103: 377-380
  • Leather RV (1998) The Cambridge prize lecture 1996 From Field to Firkin: An integrated approach to beer clarification and quality. J. Inst. Brew. 104: 9-18
  • Mathews AJD (1986) Copper Finings – A New Insight. The Brewer, October: 384-386
  • McMurrough I, Hennigan GP, Cleary K (1985) Interactions of Proteoses and Polyphenols in Worts, Beers and Model Systems. J. Inst. Brew. 91:93-100
  • Montgomery GWG, Hough JS, Mathews AJD, Morrison KB, Morson BT (1986) Proceedings of the Convention of the Institute of Brewing (Australia and New Zealand Section), Hobart.
  • Morris TM (1986) The Effect of Cold Break on the Fining of Beer J. Inst. Brew. 92: 93-96
  • Taylor R (1993) The Fining of Cask Beer. The Brewer. May: 202-205
  • Thompson GJ (1994) The Theory and Practice of Beer Clarification – Part 2 – Practice. The Brewer, November: 470 – 476
  • South JB (1996) Prediction of wort cold break performance of malt and its applications. J. Inst. Brew. 102: 149-154
  • Vernon PS (1985) Wort Clarification. The Brewers’ Guardian. 3:25-28
  • Vickers J, Ballard G (1974) Amelioration of Colloidal Conditions of Beer. The Brewer. January: 19-25
  • Ward IL https://bsgcraftbrewing.com/Resources%5CCraftBrewi… [Last Modified 11 Feb. 2014]
  • Wiles A (1951) The Action of Finings and its Relation to the Electrokenetic Properties of the Yeast Cell. European Brewery Convention Proceedings of the 3rd Congress, Brighton. 84-97

Written by our head brewer, Alistair Thompson (Hillstown Brewery)

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