It’s the bane of many a brewer. The occasional batch that just won’t clear. All is not lost. A variety of fining agents are available to encourage your beer to clear. The term "fining" refers to the process of clarifying beer, or to the agents that are used for that purpose. Finings are also described as fining aids or clarifying agents. Browsing through the finings shelf in your homebrew supply store can be confusing, especially since most stores stock finings for both the brewer and the winemaker. Some finings are used in both specialties, but some are not. It’s important to understand the distinctions when you choose a method for your beer.
Fog in the Forecast
Brewers and brewing scientists have spent many years exploring, discovering, and reporting sources of haze and cloudiness in beer. The homebrewer is generally concerned with two of them: chill haze and yeast in suspension. Haze can be the result of biological contamination; that is when your beer becomes a growth medium for wild yeast and unwelcome bacteria. But the more common form of haze occurs when naturally occurring compounds in the beer react with one another to precipitate (come together) as solids.
When large molecules of protein meet certain phenolic compounds, known as polyphenols or tannins, they latch on to one another and grow larger. As this process continues, they become large enough to be seen as haze, especially at serving temperature. That’s chill haze. In extreme cases, when the process continues unchecked, the haze forms at higher temperatures. This form is called permanent haze.
Heading Off Haze in the Kettle
Perhaps the most ubiquitous fining is Irish moss, a standard ingredient listed in nearly every homebrew recipe. Irish moss is a type of seaweed that is gathered along seashores of the north Atlantic, including Ireland — hence its common name. It’s also called carrageen, which is the name of its active ingredient. In addition to beer, components of Irish moss are used as thickening agents in ice cream, salad dressing, toothpaste, pudding, and paint. Irish moss fits in the category of kettle finings. It is added to the brew kettle, usually during the last few minutes of the boil. It helps to settle out proteins in the wort that could contribute to haze later on.
Ian Ward of Savilles, a manufacturer of beer finings in the United Kingdom, explains: "The action of all kettle finings, including Irish moss, relies on the kappa carrageenan molecule, a large molecule with a strong negative charge. When added to hot wort, some of the carrageenan dissolves. The proteins from the malt in the wort have a positive charge. They react with the negatively charged carrageenan, forming a particle that rapidly grows in size. The particles precipitate out to fall to the bottom," Ward says.
Steve Dresler, brewmaster for Sierra Nevada Brewing Co. in Chico, Calif., has been using Irish moss in Sierra Nevada products for many years. "We’ve done some trials without it and I like the results better with, especially in the original brewhouse," says Dresler. "Our whirlpool over there is high velocity and has a tendency to break the proteins apart. The Irish moss keeps the protein well coagulated and makes it settle better in the whirlpool. "In the test batches we’ve brewed without it, the trub is fluffier and not as sticky. It mixes back into the wort very easily," he says. "I’m comfortable using it because it’s a traditional fining, it’s inexpensive, and it’s virtually completely removed before the beer is packaged," he says. Modern surveys of beer chemistry indicate that Irish moss has little effect in low-protein worts, such as those made exclusively from extract. But Dresler agrees with the conventional wisdom: "Do it. Irish moss serves homebrewers well. It’s cheap, and it can’t hurt your beer," he says.
Sometimes It’s Just Yeast
Occasionally particles of yeast refuse to settle out of the beer, leaving the final product cloudy at any temperature. Why does yeast sometimes refuse to settle? Usually, nobody knows. "Every yeast has its own quirks and idiosyncrasies," says Steve Parkes, lead instructor and head brewer at the American Brewers Guild in Woodland, Calif. Parkes earned his brewing credentials at Heriot-Watt University in Edinburgh, Scotland. Yeast strains have different abilities to flocculate, but even very flocculent strains sometimes have difficulty. "Every brewer encounters the problem at some time. There are myriad things that could have gone wrong. The yeast my be tired, running out of steam after many generations; you could have too much iron in the water; it could be an amino-acid deficiency; beta-glucan from a too-high sparge temperature," Parkes suggests.
Savilles’ Ward adds that since the yeast particles all share the same negative charge, they all repel one another, continually bouncing around and remaining in a colloidal (suspended) state.
The favored traditional fining for yeast in suspension is isinglass, natural collagen from an unusual source: fish swim bladders. The swim bladder is like a narrow balloon nestled inside the fish. The fish controls buoyancy by inflating and deflating the swim bladder. "Isinglass has been used as a food additive since medieval times, and its use in beer has been documented to go back at least 300 years," says Ward. "The current thinking is that its discovery goes back to the days when wine, beer, and other liquids were carried in skins, usually of animal origin, sewn together to form a bottle. In some larger fish the swim bladder is quite large and made a perfect, ready-made vessel for liquids. Someone probably used one to store some cloudy wine and discovered quite by accident that the wine cleared inside the bladder," Ward says.
To understand how isinglass works, remember the properties of magnets. Like forces repel and unlike forces attract. Isinglass is made up of long, positively charged molecules. When introduced into beer, positive isinglass molecules latch onto negatively charged yeast, causing a clumping action. "Imagine two graduated cylinders filled with water," says Ward. "If you drop a stone in one, it will drop very quickly to the bottom. But if you drop a single grain of sand into the other, it will drift around and sink much more slowly.
"The bigger the particle, the faster it will settle. In fact if you double the size of the particle, it will fall four times faster, because the rate of settlement is a function of the square of the size of the particle. Isinglass can increase the size of a clump of yeast cells by easily 100 times," he says. Isinglass is a very effective cask fining when used properly. But using it properly can be a bit of a challenge, as Parkes explains. "It’s got to be well mixed in solution with cold water. That takes a long time. You want to keep it cool, since it will start to degrade around 68° F," Parkes says. "At the brewery we use a magnetic stirrer, which can stir indefinitely on its own. What I recommend for homebrewers is to measure the isinglass into water in a flask, stop it, and shake it very well for a good 15 minutes. Don’t be tempted to use a blender, since that will tear the molecules apart and render them useless.
"Keep it in the fridge and continue to shake occasionally for a day or two. By then, most of it will be in solution and it will be ready to use," Parkes says.
Isinglass needs acid to dissolve. The commercial powders contain an acid component built in. Some suppliers make a liquid formation, ready to use, but Parkes says the powder is probably more reliable. "There’s no way to know the history of the product you’re buying. If it’s been held at high temperatures for any length of time, it may be ineffective. That goes for the dry products, too, but they are probably not as susceptible as the liquid," he says.
Isinglass is the traditional English way of fining cask-conditioned ale. "Isinglass works very quickly. I usually hold off fining until 24 hours before serving, after the secondary ferment has been going for at least a week in the cask. The yeast need to stay in suspension to do their work during conditioning. You don’t want to fine them out until they’re finished," Parkes says.
Parkes says fining is best on a rising temperature. "That’s a tidbit that every English cellarmaster knew but you won’t find written in any technical manual, because it’s something we can’t explain. Chill the beer to a degree or two below serving temperature, then add the isinglass, shake it up to mix well, and allow the temperature to rise for best results," he says.
Homebrewer Keith Chamberlin of Riverdale, Md., used isinglass to fine his real ale, which won a blue ribbon in a Washington, D.C., area homebrew competition last year. "Some people prefer gelatin when they learn where isinglass comes from. But I wanted my real ale to be as traditional as possible," he says.
Chamberlin used the liquid version and had no problems. "I primed in the keg for secondary fermentation and let it ferment out for about a week. I added the isinglass about two days before the competition and it won first place. It was very clear," he says.
Another ale brewer, Tom Cannon of Fairfax, Va., is less confident. "I’ve had mixed results with the liquid stuff. I prefer to use the powder. I boil about two and a half cups of water to sanitize it and then chill it, mixing in the isinglass in a flask. I shake it like crazy until it gets very thick and viscous, then add it to the beer the next day.
Cannon conditions his ale in a genuine English stainless firkin, which comfortably holds 10 U.S. gallons. "The nice thing about isinglass is that it continues to work, even if the cask is moved and the yeast sediment is disturbed. It will settle right back down quickly," he says.
Cannon says he’s on the fence about isinglass only because he’s encountered such a range of results. "I might switch to gelatin, just from a stability point of view," he says.
Attacking Haze in the Glass
The agents that are effective against yeast are generally ineffective against chill haze, because the particles that form chill haze are naturally positive in charge. To get them to clump and settle — or to filter better — brewers add negatively charged finings. These compounds include silica gel (Chillguard is a common brand) and a fine powder of PVPP plastic, known as Polyclar.
Polyclar works by latching on to tannins in the protein-tannin reaction. Silica gel achieves the same effect by latching on to the protein side. Polyclar is a favorite among both professionals and homebrewers who use it. Brett Pacheco, head brewer of the Concord Junction Brewery in Concord, Mass., says Polyclar rescued his beer from a nasty haze problem. "Over time our pale ale was setting a slight haze, even after filtering," he says. "We were not sure what was going on but decided to run some Polyclar to see what would happen. It made a big difference immediately, and we have not had any problems since we began using it."
Pacheco says that subsequent analysis indicated that the brewery’s water supply had a high level of tannin compounds, feeding the tannin-protein formula needed for haze formation. "The tannin level of our beer after being treated with Polyclar is near zero. And the beer stands up to forcing tests for both chill and permanent haze," he says. Pacheco was a homebrewer for years before going pro in 1994, but he never used Polyclar at home. He says he would seriously consider it. "It gets rid of haze-forming particles but does not seem to take anything good out of the beer. It’s expensive, but in homebrew quantities that’s not much of an issue. As long as it settles enough for removal, I can’t see any reason not to use it," he says.
Homebrewer Doug King of Calgary, Canada, uses Polyclar to help clear his award-winning American-style light lager, a style that demands clarity for proper presentation. "I do not filter any more. I have tried it with success, but decent filter cartridges cost too much. I fine with Polyclar to eliminate chill haze. This is done in the secondary fermenter, after lagering," King says.
King says the beer should be chilled to near freezing to form the haze before fining. To treat five gallons of beer, he uses three heaping tablespoons stirred well into two cups of boiling water. "I do not stir or shake the beer, but rather allow the Polyclar solution to settle from the top. Use plenty of water (when mixing your Polyclar); otherwise, it can sink directly to the bottom when poured in," he says. "I have not had any success with other fining agents. I feel that polyphenols are the only haze-forming compounds that require fining. Other haze-producing things such as yeast and proteins will naturally settle out. I am a very patient brewer and try to never rush the natural processes," he adds.
Rita Liotta of Buffalo, N.Y., is also a Polyclar fan. "I hate haze because I believe there is anaesthetic aspect to the beer’s appearance. Haze distracts me from the enjoyment of the beer. "Polyclar is easy to use and effective. I’ve used it for years. I use one tablespoon for five gallons of beer. You can add it at racking, if you’re sure fermentation is over, or later on in secondary. I’ve done both. I also cold-condition my beers in the bottle in the fridge for several weeks. That helps drop out the haze, too," says Liotta.
Del Lansing of Pittsburgh warns homebrewers to be careful when adding Polyclar to beer with a fair amount of dissolved C02. "Polyclar provides perfect bubble nucleation sites. If you dump it in too fast, the result is bubbles — and a lot of them. Can you say volcano? What a mess," Lansing says. It’s important to rack the beer off the Polyclar before you keg or bottle. Although it’s inert plastic, the FDA approval is contingent on its removal before packaging. In fact because it’s safe and does not damage foam stability, Polyclar is one of the few agents permitted under the German Reinheitsgebot brewing purity law.
The procedure for using silica gel is very similar. For a double-barrel approach, professional brewers use a combination of silica gel and Polyclar. However, silica gel is less widely available than Polyclar, which is the chill-proofing agent of choice for homebrewers.
Gelatin — the same stuff used to make gelatin dessert — is a collagen protein derived from bones, hooves, and other meat byproducts. It dissolves more readily than isinglass in hot liquid. It works by the same action, but at a less effective rate. Most homebrew supply stores sell it, but unflavored gelatin from the grocery store is just as effective. About a teaspoon, or one packet of supermarket gelatin, will treat five gallons of beer. Before adding to beer chilled below serving temperature, mix it into a cup of room temperature water or beer in a small pot. Gradually increase the heat until it dissolves. Avoid boiling it, which will break it down and reduce its effectiveness.
Bentonite is a traditional wine fining made from a mineral clay, the same material from which kitty litter is made. Bentonite is not well suited to beer, because it can take up to several weeks to work and settle out.
Sparkalloid is a wine fining combining a polysaccharide sugar with diatomaceous earth. It carries a strong positive charge, working similarly to isinglass or gelatin to allow particles to precipitate (clump and sink) better before filtering. It’s not ideal for unfiltered beer but has been reported as an excellent fining agent for mead.
Papain is an enzyme derived from papaya, also used as meat tenderizer. Papain works by breaking down proteins in a very narrow temperature range. Its use was perfected by commercial breweries during the pasteurization process. It has little value in the homebrewery.