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Background to Ale
Traditional Brewing
The Basics
Beer Kits
Malt Extract Brewing
Full Mash Basics
The Details
The Mash
The Wort Boil
Cleaning and
Water Treatment

Fining and Priming

Page 4

Contents Of This Section
Biological Haze
Non-Biological Haze
Chill Haze
Haze Stabilisation
Electrostatic Charges
Isoelectric Points
Copper Finings
Irish Moss
Auxiliary Finings
Organic Auxiliary Finings
Silicated Auxiliary Finings
Beer Finings
Isinglass Finings
Isinglass Floc
Isinglass Paste
Pre-hydrolysed Isinglass
Isinglass Usage
Chill Haze Prevention
Silica Gel
Fining In Practice

Finings fall into two primary groups; copper finings that are added to the boil to assist in the coagulation of haze-forming proteins thereby assisting in their precipitation, and post-fermentation finings which assist in getting yeast to drop out of suspension. With the possible exception of copper finings, these processes are optional. Given enough time, almost any well-brewed beer will clear down unaided. It is not usual, and possibly detrimental, to use post-fermentation fining for bottled beers.

Copper Finings

Copper finings, as the name suggests, are added to the copper during the latter part of the boil to assist in the coagulation of protein, helping it to settle out as trub. If excessive protein remains in the wort it will cause a haze in the finished beer. Although satisfactory clarity may be obtained without recourse to copper finings, a protein haze is one of those things that will only become apparent when it is too late to do very much about it. It is virtually standard practice for a brewer, commercial or amateur, to use copper finings during the last few minutes of the wort boil.

Irish Moss

Irish moss is the traditional form of copper finings and has been in use for at least one-hundred years. Traditional Irish moss is derived from chondrus crispus, a seaweed that is found on the Atlantic coastlines of Northern Europe and North America. It is abundant upon the rocky Irish west coast which probably accounts for its common name, but it can be found on the west coast of Britain too. These days different types of seaweed and blends of various seaweeds are used. It is a charge-based fining system in which the negatively charged molecules of Irish moss attract positively charged protein molecules towards it, which form larger, heavier flocs which then settle out.

Irish moss is used at between 50 and 150 milligrams per litre, depending on conditions. For a twenty-five litre batch of beer, this works out between 1.25 and 3.75 grammes, which is the best part of not a busting lot and difficult to measure accurately even if a 'herb' weighing-scale is avaliable. The amount of Irish moss required is variable depending upon how much protein is present, which is dependant upon the type of malt and how much of it there is, which is roughly proportional to original gravity. The average figure of 100mg per litre, which works out at 2.5 grammes for a 23 litre batch is probably the target to aim for in the absence of better information. In common with all charge-based fining systems it is important not do overdo the dose, because this can have the opposite effect to that desired and actually stabilise the protein in solution, although the application has to be grossly overdone for it to really be a problem. However, the types of protein that contribute to head retention may be removed or reduced if too liberal a quantity is used. This does not bother me; but it may bother some.

Irish moss is available in various forms, or at least in various grain sizes, ranging from a fine powder to something resembling granules, and also in flakes, so it could be misleading to give a volumetric measurement, such as a teaspoonful. Regretfully, even our electronic kitchen scales are not particularly accurate at low weights due to the plus or minus one gram resolution of them. A higher resolution 'herb' scale would be useful, but in the absence of one I will leave you to work out what 2.5 grammes of Irish moss looks like. Most people approximate it to a teaspoonful and hydrate it by mixing it with a little water. It is added to the boiler ten to fifteen minutes before the end of the boil. Powdered Irish moss should be hydrated by mixing it into a thin paste with a little water before use.


Protafloc is a concentrated seaweed-based copper finings that is extracted from a blend of seaweeds using an alkali extraction process. It is supplied in both powder and tablet form and is used in the same way as Irish moss, added to the boiler about ten minutes before the end of the boil. Being a refined extract it is more concentrated than raw Irish moss and about a quarter of the amount is required to achieve the same ends. This brings us down to 10-50 milligrams per litre, giving an average of 30 milligrams per litre, which works out 0.75 grammes for a 23 litre batch - a quantity that is difficult to measure. Protafloc tablets are easier to use because a tablet is easier to divide than it is to weigh a small quantity of powder using domestic equipment. A half or even a third of a two-gramme Protafloc tablet is sufficient for 23 litres of beer, as usual added about ten minutes before the end of the boil.


Whirlfloc is a similar product to Protafloc. Whirlfloc-T is the product in tablet form. Whirlfloc is used at 20 to 60 milligrams per litre, which is about 1 gram for a 23 litre batch. A standard whirlfloc tablet weighs 2.5 grammes, so half a Whirlfloc tablet is sufficient for 23 litres, and is added ten or fifteen minutes before the end of the boil.

These refined tablets are much more efficient than raw Irish Moss, so it is best to be careful about not overdoing the application, otherwise head retention may be affected and a thick, fluffy sediment may be produced that could increase wort losses. Do not hydrate the tablets because they contain bicarbonate of soda which, when it hits the acidic wort, causes it to fizz like alka-seltzer which helps the tablet to dissolve easily and rapidly. By hydrating the tablet you will mess up this effect.

Auxiliary Finings

Auxiliary finings are optional post-fermentation finings that are used in conjunction with isinglass finings to produce brilliant clarity in cask-conditioned beers, but they must not be added at the same time as isinglass. Auxiliary finings have a strong negative charge which attract positively-charged particles to it, swamping their positive charge and forcing them to have a net negative charge. The beer then contains only negatively-charged particles, thus when isinglass (which is positively charged) is added later, all the particles are attracted to it, which aggregate until they are heavy enough to drop out of suspension. This greatly enhances the performance of isinglass; not only is a brighter beer the result, but the quantity of isinglass required is usually less than half the normal dose. Auxiliary finings are not a necessity and are not often used in home brewing. There is probably little point in using auxiliary finings without the subsequent use of isinglass or similar types of finings because the auxiliary finings have the function of preparing or preconditioning the beer to improve the action of isinglass or similar. There are two types of auxiliary finings:

Organic Auxiliary Finings

Organic auxiliary finings are similar to, and behave in the same way as, copper finings, but they are NOT a substitute for copper finings. Like copper finings they are usually based on seaweeds and possess a negative charge. Auxiliary finings are added post fermentation, usually to the cask at the time of filling. They must not be added at the same time as isinglass finings because they possess opposite charges will cancel each other out, making both the auxiliary finings and isinglass finings ineffective. Auxiliary finings should be added at least twenty-four hours before isinglass finings. Composition of auxiliary finings vary, but they are usually added at a rate of between 1 and 3.5 millilitres per litre. 2 millilitres per litre is a reasonable average which amounts to 50 millilitres per 23 litre batch, which is at least easy to measure.

Silicated Auxiliary Finings

Silicated auxiliary finings are an inorganic form of finings based on sodium silicate. Silicated finings are available in various forms; some are wholly inorganic finings, others are blended with organic auxiliary finings mentioned above. Like organic auxiliary finings they possess a negative charge and will attract positively charged proteins, only this time silicated finings have increased effectiveness against the types of protein that contribute to non-biological hazes. It reduces the possibility of a chill haze being formed in the final beer by removing some of the components that cause it. Silicated auxiliary finings are very fast acting and are a useful addition to a beer to give that professional polish. Brupaks auxiliary finings are silicated. They are added at the rate of between 2 and 7 millilitres per litre. 4 millilitres per litre is a reasonable compromise.