Fining Beer for Clarity
First, what does “fining” mean? Well, this is another piece of brewer’s jargon, like “grain bill,” “knock-out” and calling brewing water “liquor” — indeed one 18th century writer records that anyone using the word water in the brewery would be charged sixpence (a significant sum of money in those days). Fining is the process of adding a substance that will cause the suspended yeast (and other solids) to clump together and settle to the bottom of the vessel, leaving clear beer as the supernatant liquid. That is it makes the beer “fine.”
In fact, fining is brewer’s jargon for the process that is more widely known as flocculation. This term is applied to the process where tiny particles suspended in a liquid are caused to form bigger particles that can then settle out of suspension. Often the suspended particles are held so because they carry like surface charge and repel each other. Reduction of this charge by altering pH, such as by addition of calcium ions, results in agglomeration and settling of the particles, in a process known as coagulation (as distinct from flocculation).
If instead a molecule capable of absorbing onto the particles and large enough to join several particles together is added, we have true flocculation. The added molecule, usually a high molecular weight water-soluble polymer is known as a flocculant. Please note the distinction from flocculence, which is the property shown by particles that are flocculant. There are a variety of flocculants available, some of them naturally occurring such as carrageenan (Irish moss, used in the kettle to flocculate trub), gelatin and isinglass (used as finings in beer). There is also a wide range of synthetic flocculants, dominant among which are very high molecular weight polyacrylamides and polyacrylic acid and its derivatives; I am not aware that any of these have been used to clarify wort or beer. Note that other polymers used in beer treatment, such as Polyclar and silica gel are not flocculants — they are insoluble and are used as adsorbents for proteins and tannins that cause chill hazes in beer.
You have probably come across these terms in regard to yeast, since the suppliers usually give a figure describing how flocculent the particular strains are, based on a specific settling test.
All yeasts show some tendency to flocculate without the addition of a flocculant, but what we are concerned with in fining is those particles that do not flocculate and settle only slowly. These fine particles do not settle well simply because they are too small to do so, though they will settle under gravity, given sufficient time.
What are finings?
Finings are quite specifically substances to assist the removal of suspended yeast from beer, that is, to clarify the beer. There are really only two products that have been used to any extent in brewing, and they are gelatin and isinglass. They are somewhat similar chemically, in that they are both proteinaceous, which means they can carry either a negative or positive charge according to the conditions of their environment. That is good, for it is these charges that enable the molecules to adsorb onto the surface of yeast particles. They are both quite high in molecular weight (MW) — that is, they are much bigger in size than “regular” molecules — with isinglass being much higher MW than gelatin.
Both isinglass and gelatin are “natural” products in the sense that they are processed from natural materials. Gelatin is obtained by hydrolysis of collagen in byproducts from animals, such as bones and skin. It has a wide variety of uses such as capsules for drugs, a general thickening agent in foods, and, of course, as the principal ingredient of Jell-O. Isinglass is a collagen derived from fish swim bladders, originally those from Russian sturgeons, but now from a variety of other fish from around the world. Its use is largely limited to fining beer, and it has been used as such in Britain since the 18th century; it has also, of course, been used for fining wines.
Both products are available as purified solids and are quite stable against MW degradation in that form; isinglass may also come in a liquid form as an aqueous solution. Gelatin in fact can be treated fairly roughly, in that it is dissolved in hot (but not boiling) water without any degradation of the molecule, which makes it easy for the amateur to use. Isinglass, on the other hand, is more fragile and must be dissolved at room temperature or lower, usually in an acidic medium; in fact solutions will degrade relatively rapidly at temperatures above 70 °F (21 °C). When it does degrade it is not just a matter of losing MW, but of the polymer chains actually unraveling, becoming no longer useful as a flocculant. In the British brewing industry, it was common practice in the past to dissolve the isinglass in soured beer, but that is definitely not a practice followed today! Note that these two fining agents have little effect on the development of chill hazes as the beer is stored cold. The sole reason for using these two products is to remove yeast from suspension.
When to use finings
Both products can be added to a beer as a final treatment when it is kegged or bottled, with the aim of ensuring that the yeast settles out quickly and the beer becomes almost as bright as a filtered beer. Having said that, this is where MW comes into play – remember the bigger the molecule the bigger the flocculated particle (or floc) and the faster it settles. Therefore, use of gelatin will result in slower clarification than will the higher MW isinglass. As a result, gelatin is only moderately useful as a fining agent, but is used by some brewers to assist in filtration. That is be-cause it forms relatively small, tightly formed flocs that will not block the filter medium and will easily form channels for the liquid to pass through and come out clear on the other side.
Isinglass is, in my opinion, the best fining material, for if properly used it will form relatively large, rapid settling flocs. These will form a tightly packed sediment that is not easily disturbed when the cask or bottle is moved. And if the movement is violent enough to disturb the sediment it will readily and quickly settle out again. That of course is a valuable ability, and for that reason isinglass is widely used by commercial brewers who want to ship out a beer quickly and have it soon be clear and ready to serve in the pub or bar cellar. In short, that means that isinglass fining is perfect for cask-conditioned beers, where yeast must remain in the beer so that a conditioning fermentation can take place in the cask. It is widely used for that purpose in Britain today.
But what about homebrewers? Well, it’s arguable that if you are bottling your beer you do not need to fine it. Any suspended yeast needs to settle only a short distance in a bottle compared to that in a keg or cask. If you are planning to leave the beer in bottle for 2-3 weeks or more and have a reasonably flocculent yeast the beer should be nice and clear when you come to drink it. If, however, you want it ready quicker than that, or more importantly you have a low flocculating or “powdery” yeast, then you should consider fining the beer.
In the case of kegging, the yeast has to settle quite a long distance and you are drawing off the bottom, so you want the beer to be below the outlet tube when you draw it off. Again, if you give it sufficient time the yeast will settle on its own, but if it doesn’t settle well, or if you want to drink the beer within a few days of kegging, then fining is the answer. Remember that if you keg an unfiltered brew you are essentially producing a cask-conditioned beer! Personally, I make it a practice to fine all my kegged beers, for what that is worth.
How to use finings
Let’s start with gelatin. You will need about 1⁄2-1 teaspoon (4-8 g) of the powder (regular cooking grade is fine) per 5 gallons (19 L) of beer. Some authors suggest adding it to cold water and allowing it to form a gel before heating the mixture. I prefer to add it to cold water (about 100 ml, or half a cup) and stir it thoroughly to wet the particles. This mixture is then heated (not boiled), while stirring thoroughly until all the particles have dissolved. The solution of gelatin is then added to the beer after it is racked from the secondary (see later). After the addition it is best to gently agitate the container before bottling or kegging. After 3-4 days look at the bottle or take a sample from the keg to judge how much progress has been made. It may, however, take 2-3 weeks before the beer becomes properly clear.
If it does not do so by this time you will just have to be patient, and be prepared to double the dose of gelatin in the next brew.
Now for isinglass, which is tricky to prepare from scratch. But, you can buy it as a ready-prepared liquid, in which case you should add it (again to beer racked from secondary) as directed by the manufacturer. You should be aware that such solutions may deteriorate if they have not been stored cool, or if they have been exposed to heat during transport.
There is a brand of freeze-dried isinglass powder that, when dissolved, is claimed to be stable at room temperature. The supplier recommends using 1-2 grams per 5 gallons (19 L) of beer, and dissolving it in around 100 ml (1⁄2 cup) of cold water using a blender. This mix is also added to the beer after racking from the secondary, with gentle agitation of the container.
My own approach with the powder (freeze-dried or not) is somewhat different, because I prefer to make a large batch (at least 1 quart/1 L) up to 3-6 months before I intend to use it. I put 250 mL (~1 cup) of cold water in a 1-quart (1-L) glass jar, add 2 grams of mixed acid (available from any winemaking supplier), drop in a sanitized stirring bar, and put the jar on a magnetic stir plate. I adjust the speed to give a full vortex in the liquid and then very gradually dribble the powder (0.35 oz./10 g) into the side of the vortex (takes a bit of practice!). When it is all added, the solution soon becomes too viscous to stir further, and I remove the jar for the stirrer, add cold water to bring the volume up to 1 quart (1 L), and place it in the refrigerator. Every time I go to the fridge for a beer I give the jar a good shake, then put it back. The result is a 1% solution of isinglass and I add this at rate of 4 oz. (120 g.) to 5 gallons (19 L) of beer, using the procedure above.
Note that the reason for adding finings to beer racked from the secondary is that if there is too much yeast present they just will not work properly. The idea is to have a maximum of 5 million yeast cells/ml, and that should be about what you have after a week or so on secondary. (I have checked that with a cell count under a microscope, but you won’t need to do that).
Conclusion
I have written this to provide you with another weapon in your brewing arsenal. I find them useful, you may not find that you need them; if that is the case, that’s “fine”!
