Nick Carr on March 2, 2016 10 Comments Crystal clear beer is a much desired and sometimes very elusive thing for the everyday homebrewer. Like the unicorn it can be a vague and a seemingly mysterious creature. But unlike the unicorn of myth, this one does not have to remain uncaptured. Clear beer is within any homebrewer’s grasp. Table of Contents Causes of Haze Brewing Practices for Clear Beer Additives Kettle Fining Fermentation Fining Stabilizing Aids Granted, beyond a pride-driven need for presentation, clear beer isn’t truly necessary for the homebrewer, at least not in the same sense it is for a working brewery trying to peddle its wares to a discerning and picky public. Though not crucial to creating a great brew, it is something to aspire toward, for it speaks to a higher understanding and more precise manipulation of the brewer’s craft. This article will hopefully help you wrangle this brewing unicorn. First, I will present the entire brewing process step by step, from ingredient selections that can make a marked difference, to the serving of your finished beer. Some of the changes are quick tweaks to a basic brewing practice through better understanding of why and how haze forms. Others, such as using a filter are more costly, both in time and money. Which tips you choose to employ in your personal search for the “brewing unicorn” is completely up to you. Afterwards, I will present, in detail, what finings do and what types of fining agents are available. CAUSES OF HAZE Biological particles — This includes both the brewers yeast you put in and any wild yeast that might find your beer, and bacteria. These can either form a permanent haze or a temperature dependent haze and they will affect flavor and aroma. Bacteria and wild yeast are the result of poor sanitation practices. There is not a whole lot to be done about them, but to learn, and try again. Non-biological particles — This can include particulate matter, protein-polyphenol complexes, carbohydrates like starch, and calcium oxalate. These produce a temperature dependent temporary haze. The biggest contributor of the bunch is protein-polyphenol complexes. Reactants Another way to break down the sources of beer haze, especially non-biological, is by the reactants (particles) and the facilitators of the reactions. Proteins — From the malt. Polyphenols (tannins) — Both flavanoids and tannoids are polyphenols. But it is only the larger tannoids that form haze. Flavanoids protect your beer from oxidation giving it some flavor stability, but over time these flavanoids, through their reaction with oxygen form bonds with one-an-other and become tannoids. Tannoids can then form bonds to, and between, proteins, becoming a bridge, and creating particles whose molecular weight can jump exponentially, until light reflects, and… you have a haze. Other Particulate Matter — From yeast, malt and adjunct carbohydrates, and bacteria. Facilitators Oxygen — Is a catalyst for the bonding of flavanoids, which make tannoids. Heat — Speeds polyphenol reactions, but they only become visible upon cooling. Light — Thought to speed polyphenol reactions. Time — The longer a beer is stored the more time reactions have to take place. Transition metal ions (Cu, Fe) — Sometimes found in old brewing equipment or even filter elements, copper and iron are catalysts that can shuttle between oxidation states essentially feeding oxygen to the polyphenols, speeding up the reaction. Stoke’s Law The clarity of your beer is governed by Stoke’s Law, which describes the settling rate of particulate matter in a medium. Stoke’s Law: v = velocity of settlement ρp = density of the particles ρr = density of the fluid r = radius of the particle g = acceleration due to gravity η η = viscosity of the fluid Looking at this equation we can see: The larger the particle’s radius (size) the faster it will settle. The greater the difference between the particles density and the fluids density, the faster particles will settle. The greater the pull of gravity the faster particles will settle. So, really what this equation tells us is exactly what we can manipulate to make particles settle faster. You can manipulate gravity, by putting your beer in a centrifuge (not really an option for most homebrewers) or you can make the particles bigger. So, how do we minimize particulates and then make those particulates left bigger? We can do this by “gearing” our brewing practices toward clarity. These tweaks to our brewing practice also have the added advantage of helping us create a higher quality brew. We can also add fining agents and other additives to assist us in the clarification process (more details on different additives down below). BREWING PRACTICES FOR CLEAR BEER Choose Your Ingredients Wisely: Before we get into specific ingredients it is worth mentioning that aspirations of a crystal clear beer should not dictate complete changes to your recipes. Clarifying should always take a backseat to a style’s authenticity and your own creativity. Grain: Much of the polyphenols and proteins that cause haze comes from the malt. The higher the protein content of the malts you use the more likely it will create haze. Use well-modified malts with protein contents under 12 percent. Low polyphenol or polyphenol free malts are available and using them can increase clarity, but care should be taken here. Some polyphenols are needed in both your wort and finished beer. During the mash and boil polyphenols help to precipitate out proteins by bonding with them and creating larger particles; and in finished beer flavanoids give some oxidation protection. Hops: Though the hops may only contribute 30% of the polyphenols this is a disproportionately large percent when comparing how much hops (a few ounces) to how much malt (9 to 12 pounds) you use in making a 5 gallon batch of beer. Because polyphenols are found in hop’s vegetative material you may come to the conclusion that exclusively using hop oils and extracts is the way to go. Dropping your polyphenol load by 30% percent in a single stroke sounds pretty good, doesn’t it? But the same concern arises as with using polyphenol free malt. You want some polyphenols in your boiling wort to help pull out proteins and create that nice mound of trub at the bottom of your kettle. So, care must be taken and some experimentation might be the order of the day. Yeast: Choose yeast based on it flocculating characteristics as long as it doesn’t contradict the beer style. Medium to high flocculating yeast will eliminate a lot of the particulate matter stemming from this ingredient. However, you also don’t want a yeast that’s gonna settle out too quickly leaving you to roust it back into action. Adjuncts: High nitrogen adjuncts such as wheat, unmalted barley, and flaked grains increase the concentration of protein in your beer. Brewing: Milling: If you happen to do your own grain milling, look to your setting. The grain husk carries a large part of the malts polyphenol load. If set too fine the mill will smash the husk making it easier for the polyphenols to be released. You want to crack the husk not pulverize it. The Mash: Controlling you mash temperature is vitally important for correct enzyme activity, but also helps break down large gelatinous proteins. If using well-modified malt and few adjuncts you can often use a single step mash to the saccharification rest temperature of 148–158°F. But a two-step mash is recommended for those using under-modified malt or more than 25 percent wheat, oatmeal, unmalted grain, flaked barley, or rye. The first rest would be at a temperature of 113–133°F for 15 to 30 minutes. Called a protein rest, this step may give the enzyme proteinase time to break up long chain proteins and make the starches more accessible for conversion. Sparging: If doing an all-grain brew sparging is a moment of truth. You are looking to get a certain amount of fermentables and you don’t want to waste any of that precious liquid, so near the end of the sparge you might be tempted to start messing with your grain bed, pressing on it, trying to get every drop you can out of it (this becomes even more true if you realize you’re not hitting the gravity or volume you want). Don’t! Remember, polyphenols come from the grain husk. When you “wring” your grain bed a flood of polyphenols make it into your wort; and even without pressing the bed there is an astounding leap in the polyphenol content between the first runnings and last runnings of a sparge. So, take this into account when you build a recipe. Adjust the grain bill so that you can stop sparging earlier. A lot of brewers stop their sparge when the runnings have dropped to say, 2° Plato (about 1.008 SG). Another couple things to keep in mind when sparging are your grain bed pH and the water temperature. If pH is above 8 or the water temperature is too hot (above 180°F) more polyphenols will leach out of the grain bed and into your wort. The Boil: Let it roll. When you boil don’t be afraid to let it boil. A vigorous rolling boil is optimal for denaturing proteins and creating a good trub pile. At the last 15 minutes of the boil adding copper finings, such as Irish moss (explained in detail down below) can help proteins bind together and drop out of suspension. Cold Break (The Big Chill): Once you are done with the boil it is very important you quickly, and with sanitation in mind, lower it to yeast pitching temperature. This is another chance to bind proteins and polyphenols together and get them out of your beer. To do this you will need a wort chiller if you don’t have one yet. They are well worth the investment to either build, if you’re handy, or buy outright. Also stirring your kettle, giving a whirlpool effect, as the wort chiller runs helps it cool faster. Fermentation Dry Hopping: Dry hopping will create a hazy beer. That’s just the way it is. And if you’ve dry hopped, and have the capacity to filter… Don’t. Filtering will strip much of the aromas and flavors you’ve just worked so hard to get into your beer. It’s going to be hazy… let it. Yeast: Again try to use medium to high flocculating yeast to ensure it settles out as much as possible. After Fermentation Cold storage: Transfer your beer to another container and cold condition your beer at around 30°F for at least 3 weeks. A week prior to bottling you might throw in a post-fermentation fining agent to help more particulates drop out of suspension. Keep your racking cane well clear of the bottom of the fermenter. As you get closer to the bottom mark these last bottles somehow and keep them for your own enjoyment. Try to keep your beer stored in a relatively cool place. Realize that cyclic warming and cooling of finished beer will create a permanent haze and the longer you store it the more time reactions have to take place. This also is where filtering would come into play. I don’t know too many home brewers who have taken the leap to filtering and there are enough online resources about filtering that I don’t feel the need to go into much detail here. A couple good tips though. If you are going to filter, do it while your beer is cold. This allows all the cold haze that has formed to be filtered out. If you do it warm much of the haze will be absorbed and end up in your finished beer. Also, along the same lines, ensure that your filter is cold. If you’ve just sanitized your filter with scolding hot water, then you send cold beer through, it has the same affect. Many of the polyphenols and proteins will be reabsorbed before the beer even hits the filter. Serving: If serving from a keg pour yourself the first glass. More particulates will have precipitated out and will likely come out in the first pour. Drink it don’t throw it away. After all, it’s still good beer. If you bottle, pour carefully, leaving the last quarter inch or so in the bottle. This keeps any particulate matter out of your glass. Using just a few of these techniques will go a long way in creating clear beer. Some require thought and perhaps some experimentation (amounts of non-polyphenol malt to use), others require patience (cold storage), some require extra funds and time (filtering), and some only require you drop an addition into the beer (clarifying additives: discussed further below). Find what works best for you and decide how far you’re willing to go to capture that unicorn. ADDITIVES We’ve already discussed brewing practices that will go a long way in allowing you to create crystal clear beer. Now, let’s talk about forced clarification, that is, additives that speed and increase clarification, and can decrease aging time. It is important to point out here that these finings should not be thought of as a shortcut replacement to the brewing practices already discussed. It is always good to operate under the “less is more” idiom. The fewer things you can get away with putting in your beer and the fewer ways you have to manipulate it… the better. How Additives Work If we look again at Stokes Law (the law that describes the settling rate of particles in a liquid medium). As mentioned in the first part the main way a homebrewer can clarify beer is by increasing particle size and that’s what finings do. They increase the (r) radius variable of this equation by having an electrostatic attraction to particles in the beer. As these particles combine their molecular weight increases and they fall out of suspension faster. Finings can be broken into two main categories, dependent on when they are added to the wort. Kettle finings, also called copper finings (a name coming from when copper kettles were used extensively in England) are added 10 to 15 minutes before the end of the boil. The other category is those finings added at the end of fermentation. There is also a third — we’ll call it subclass — of finings. Auxiliary finings make it possible for fermentation finings to “grab” more particles then they otherwise could. KETTLE FINING Really there is only one kettle fining, but it comes in three different forms. Traditionally Irish moss or Chondrus crispus was used for kettle fining. It is a species of red seaweed found off the coast of much of Europe and along some of the Atlantic coast. It is said that Irish moss was first added to the wort to prevent witches from spoiling the brew. This is partially true, Irish moss does keep beer stable longer by removing proteins, though we are pretty sure, these days, that those proteins come from malt and not witches. Today another red seaweed Euchema cottonii is often used because it has a higher level of K-carrageenan, the ingredient that actually binds up proteins. Chondrus crispus contains only about 30% K-carrageenan while Euchema cottonii contains almost 70%. The same action that binds protein to this K-carrageenan has been put to use in much of the food industry as a thickener and stabilizer (think yogurt). How Irish Moss Works K-carrageenan disassembles from a helix shape when heated. This allows its negatively charged sulfate groups to latch on to the positively charged proteins and as the wort cools they reassemble creating large particles that drop out of suspension faster. The ability of the K-carrageenan to neutralize the positive charge of proteins is called the zeta potential. This becomes important when looking at dosing. You are trying to get as close to a neutral zeta potential as possible; using too little of the product will not neutralize all the positively charged proteins, but using too much can actually create a negative zeta potential. This will create sediment that is unpacked and fluffy, making racking a drag, and loss of quality beer likely. Forms of Irish Moss Irish moss is offered in three forms — powder, granular, and tablet. Powder — The powder form is probably the least favorable for the homebrewer and is often recommended for breweries larger than 30 barrels. Potential measuring discrepancies at doses small enough for homebrew batch sizes make it tricky to use. It also needs to be mixed into cold water prior to use. It is not often sold at homebrew supply stores though there are places to purchase it on the internet. Granular — The granular or flaked form is often available at homebrew shops. It is cheaper than the powder because there is less processing involved and it is easier to use then the powder requiring no slurry preparation before casting. Follow the manufactures instructions, usually something like one teaspoon per 5 gallons, and add 10 to 20 minutes before the end of the boil. Tablets — Tablets are probably the most convenient for the small brewer. You will pay a bit more for the convenience but it can be worth it. Probably the best known product in this form is Whirlfloc, which combines Irish moss and a purified form of carrageenan into an easy to use tablet. Though a bottle’s instructions may say to use one tablet for a 5 gallon batch, half a tablet should be plenty and allows you stretch your supply a bit. FERMINTATION FINING Isinglass and gelatin can both be used to fine beer during the fermentation. Isinglass is effective against yeast and when combined with an auxiliary fining can be effective against proteins and polyphenols also. Gelatin is effective against both proteins and polyphenols. Isinglass Isinglass is a very pure gelatin made from the swim bladders of certain fish, traditionally sturgeon; though today other fish, such as Nile perch and cod often supply the bladders. We may wonder what made brewers put fish parts in their beer in the first place, but it actually is quite easy to make a guess at how this came about. Animal bladders were extensively used to carry water, wine, and probably beer. Beer pH could have dissolved some of the collegian and when it was poured some astute brewer noticed his beer was magically clearer. How Isinglass Works Isinglass has a triple helix form with positively charged edges allowing it to interact with negatively charged yeast cells and increase the size of fluc. Often other particles get trapped in the matrix of isinglass and yeast adding their weight to the fluc and this larger fluc settles more rapidly (as described by Stokes Law). Isinglass will not react directly with any neutral or positively charged particles. So, if used by its self, many particles will be left behind. Here is where the auxiliary finings come into play. Gum acacia, also called gum Arabic, and silicic acid prepare the way for Isinglass. They label everything with a negative charge so that more particles interact with the positive charge of Isinglass. Probably the best known silicic acid product is Biofine Clear and gum Arabic is in several head retention aids or can be purchased on its own. These products can also be used on their own, like Isinglass, they will not perform quite as well by themselves, but they area an option for vegan brewers. Forms of Isinglass Isinglass can be found in four forms — liquid, milled, powdered or freeze dried, and paste. Powdered or Freeze Dried — The most common, especially where homebrewing is concerned is powdered or freeze dried. This form is easy to use, dissolves quickly and gives reasonable clarity, works really well if you are going to filter. Liquid — The liquid form is more common in England, has a very short shelf life, and is hard to find as an export. Paste — The paste is very expensive, has a 6 month shelf life, and gives excellent clarity, but may be hard to find. Milled — The milled and blended form may also be hard to find. This form dissolves slowly but gives very good clarity, and is great for those who are not in a hurry. Tips For Using Isinglass Follow the directions on your particular isinglass product. Once in liquid form the helix will start to unzip, rendering it useless, around 68°F. So it must be kept below this temperature, though just to be safe I’d even try to keep it below 50°F. Liquid isinglass will degrade rapidly even if kept cool. Use it within 3 weeks. Make sure the beer is cold when you use it. Isinglass can only remove insoluble material and remember that the amount of particles dissolved in your beer is temperature dependent. To work properly it must be well mixed into the beer. STABILIZING AIDS Stabilizing aids are those agents that deal with proteins, polyphenols, or both, during the maturation stage. This means adding them to the keg, if you keg, or into a secondary or tertiary carboy if you’re going to bottle. Gelatin I’m putting gelatin down here with the stabilizing agents, but it can be used, much like isinglass, at the end of the fermentation. It is an easy and cheap fining agent. Common unflavored gelatin can be purchased at the grocery store. Derived from the hooves of some animals, this collegian based fining agent works much like isinglass, and will help precipitate out both proteins and polyphenols. Carefully follow the instructions when adding this to your beer, if too much is used it can stripe away flavanoids and even color. Enzymes These can be applied at the end of the fermentation stage also. The most common may be papain which is derived from papayas, but there is also ficin (figs) and bromelain (pineapples). How well any of these enzymes work depend on the purity of the product, but they basically chop up proteins (they do not have any effect on polyphenols). They will remain in the beer and can affect its flavor. Enzymes also do not discern between the hydrophilic proteins and the head forming hydrophobic proteins, so head retention may be adversely affected. Tannic Acid Made from oak gules, tannic acid reacts with proteins, but not polyphenols. Correct dosing is important because too much can give your beer a tannic taste. It forms a defuse sediment that can be hard to rack around or filter through. It is not used much anymore. Silica Gel Silica gel is the same stuff that makes up desiccant packages, found in food, clothes, etc., but don’t use these! Two common silica gel brewing products are Chillgaurd and Kielelsol. Silica gel is negatively charged so proteins adhere to pores in the silica. But it only “grabs” the hydrophilic proteins, meaning head retention is not affected. But, high dosage is required for it to be effective if used one its own, which can affect foam and flavor. It also completely settles out of the beer so as long as your rack carefully, none of it will end up in your bottles. PVPP (Polyvinylpolypyrrolidone) Commonly found under the product name Polyclar this is a fining agent made of powdered PVPP plastic. This is an effective additive against polyphenols while itself, being completely insoluble, so it will completely settle out. It can be expensive but creates good stabilization, though overuse can affect flavor stability. A combination of PVPP and Silica gel at lower dosing rates may give an overall good result on both the polyphenol and protein front, but some dosing experimentation would be needed need to find that happy middle ground. Takeaways I know there is a lot of information throughout this article. Take what you want from it. Start small. Ask yourself some questions. Do you want to use only natural additives? How much are you willing to spend? Are you willing to take some time and experiment? The answers will effect which options you may want to look into. I’d always suggest getting brewing practices down cold before starting to use additives, just because it is easy to fall into using fining agents to compensate for less than optimal brewing practices. There is also no way you need all the finings listed in this second part. Find the ones that suit you, experiment a bit, and you will come to a regimen that works best for you and your individual brewing setup. And, remember, if it comes out less than pure crystal, clarity does not affect the drinkability of an otherwise well-crafted beer. Cheers!