Rx for Brewing Problems
In a classic scene from a “Three Stooges” episode, Larry, Moe and Curly discover what has caused their freshly brewed beer to wildly churn and froth. As the amateur brewmasters were distracted by phone calls and other diversions, they each, in turn, added more yeast to the brew. These tripled efforts eventually caused their 185 bottles of Panther Pilsner to erupt with volcanic fury, dousing them with bazooka blasts of beer and foam. Woob! Woob! Woob! Woob!
Since these hijinks were simply for our viewing pleasure, we can forgive the madcap trio their lack of technical accuracy when it comes to making beer (since when do you brew, ferment and bottle all in the same day?). After all, their blunders are meant to be entertaining. But it’s not so amusing when these blunders happen to you.
Making beer at home is fairly simple; making good beer on a consistent basis is a bit more difficult. The process is fraught with potential problems all the way from brewing to bottling. In this article we will identify the most common mistakes made during the brewing process, along with straightforward corrections and suggestions on avoiding these mistakes in the future.
Recipe For Disaster?
A handful of problems in brewing begins with the recipe, with weights and measures being among the most prevalent. It’s not just a matter of the “correct” ingredients, but using the proper quantities of ingredients. Novice brewers sometimes fail to note the relationship between the amount of malt extract (or base grain) and the resulting specific gravity. Also important is the relationship between the amount of malt extract and the quantity of hops required to properly balance the flavor of the beer. Specialty grains can easily be misused, with the “if a little is good, a lot is better” mindset. Judicious use of specialty grains — especially dark roasted grains — is important. Additives are often used with little knowledge of their effect on the beer. And adjunct sugar content should be kept to a minimum (the effects of these sugars on the taste of your beer will be covered later).
Time and temperature are also important measurements to consider. Specialty grains should be steeped —note that this is done at sub-boiling temperatures of 170° F or so — for about 20 to 30 minutes in order to maximize the yield of their color, flavor and scant sugars. For most brews, a good 60-minute rolling boil is considered standard practice. This time is sufficient to create “hot break” (precipitated proteins that separate from the rest of the wort) as well as complete isomerization (dissolving) of hop alpha acids which imbue the beer with bitterness. DMS (dimethyl sulfide) removal is another important feature of the boiling phase.
Time and temperature also represent two of the three most important variables in mashing (pH level is the third). On the opposite end of the thermometer are the cool temperatures required to properly ferment and age lagers — not to mention the doubled length of time required for the traditional lagering process.
There are plenty of good resources for beer recipes out there, in print and online; use them to your brewing advantage. Always remember to pay attention to weights and measures, times and temps.
Mashing and Sparging Problems
Mashing and sparging procedures often cause all-grain brewers — even experienced ones — to suffer conniptions. This is due to the number of procedures required to brew beer from grain, multiplied by the number of variables involved.
The ultimate goal of most grain brewers is to achieve high efficiency levels, that is, to derive the greatest possible amount of soluble sugars from their grain. When minimum efficiency levels are not reached, the resulting beer will either be thin and lifeless or the wort may have to be condensed into a smaller volume.
Here are some ways to improve your mash efficiency. Start by using more highly modified malt, which offers a greater quantity of fermentable sugars right from the start. British malts are typically more highly modified. Correct milling of grain is also important; proper milling requires that the husk be cracked open to expose the starchy interior without reducing the grain to dust that will later cause sparging problems. Make sure you have the correct mash consistency, i.e. water-to-grain ratio. A good ratio is one and one-third quarts of water per pound of grain in your recipe (9 lbs. grain = 12 quarts water).
Now pay close attention to the three important mash variables of time, temperature and pH level of your mash water. Once the grain and water are mixed in your mash tun, you need to set the proper pH; measuring can be done with pH test papers or an electronic pH meter. A pH reading of 5.0 to 5.5 (slightly acidic) is considered optimum for most beer styles. You can adjust the pH of your mash by adding a tablespoon of gypsum to lower the pH (or acidify the mash) or by adding calcium carbonate or sodium bicarbonate to raise pH (or make the mash less acidic). Precise mash temperature is important because key enzymes, which are needed to make the grain’s endosperm (where the maltose sugars are stored) soluble, perform differently at various temperatures. Proper temperature and timing is needed to break down and extract the maltose sugars during mashing procedures.
After mashing has been completed, you need to drain the syrupy wort away from the grain bed. In doing so, you want to leave behind as much of the particulate matter as possible and you want to recover as much of the sugary liquid from the grain bed as possible. The grain bed itself is a practical filter, so re-circulating the wort back through the grain bed will allow you to clear the wort of a lot of particulate matter. In order to do this efficiently you have to keep the sparge water and the grain bed at the proper temperature to allow the thick wort to flow better. Remember to maintain proper pH levels in the sparge water, and not to over-circulate the wort. Otherwise you risk extracting harsh tannins from the grain.
Most all-grain brewers would agree that there’s no frustration in brewing worse than a stuck sparge. This means the grain bed becomes compacted and will not allow the sparge water to pass through it. This problem can be avoided or minimized by employing a couple simple methods. First, always sparge at a steady rate; add fresh sparge water at the same rate that the wort is being drained. Never let the water “channel” down through the grain. Always keep a shallow pool of sparge water at the top of the grain bed as well as an “underlet” or pool of water below or at the bottom of the grain bed. Finally, when brewing any beer style whose recipe calls for a large quantity of huskless grains, such as wheat or rye, consider adding yeast hulls to the grist. These flavorless hulls work to keep the grain bed porous.
Taking another tack, you might want to give “no-sparge” mashing a try and simply drain off the “first runnings” of the mash. Should you choose this method to brew a full-volume beer, you’ll want to modify your recipe: Because you are not sparging the grain bed, you won’t be achieving the full potential of your mash and, therefore, you won’t reach the target gravity. Increase the base grain by a couple of pounds per 5-gallon batch. Whether you sparge or not, re-circulating your wort to clarify it is still a good idea. (For more on this technique, see “Skip the Sparge” in the May-June BYO.)
Lag Time
As most of us know, yeast quality and quantity is of great importance, the lack of which can lead to some common problems. First up is a problem referred to as long lag time. This is the amount of time elapsed between pitching the yeast and visible signs of active fermentation. The golden rule is simple: the shorter, the better. In other words, the sooner the yeast kicks in and begins fermentation, the healthier and better-tasting your beer is likely to be. A lag time of 12 hours or less would be considered good; a lag time of 24 hours or more may be inviting a host of problems. It’s during lag time that any bacteria present in your wort or on your brewing equipment is likely to begin contaminating your beer.
So, how can a brewer reduce lag time? There are a number of ways. First, make sure the wort is properly prepared for fermentation. This means chilling the wort down to room temperature (typically between 65–75° F). Chilling hot wort can be done with cold sink baths (placing the brewpot in a sink filled with cold water), by using a wort chiller (either the simple immersion type or the more effective counterflow type) or by adding cold top-up water in the fermenter. If you really want to chill your wort quickly, you can do all three.
Also be sure your wort is aerated — after it has been chilled. Yeast requires oxygen for reproduction, which is an important opening phase of fermentation. You can aerate wort by vigorously pouring the cooled wort into the fermenter (the least efficient method), by adding aerated top-up water or by using a sanitized “beer stone” which, when hooked up to a canister of oxygen or to an air pump, diffuses air bubbles into the wort.
Now make sure you have the proper quantity of yeast on hand for pitching. When using sachets of dried yeast, always opt for larger sizes or double up on packets, and always “proof” or re-hydrate the dried yeast in water before pitching. When using liquid yeast strains, consider making what is commonly called a “yeast starter.” This is highly advisable at all times, especially when the yeast is old or the beer has a gravity of 1.060 or higher. Making yeast starters for lager beers is standard practice; doubling the typical amount of bottom-fermenting yeast is considered crucial to making good lager beer. When it comes to yeast, more is generally better.
Before pitching the yeast into the wort, it’s a good practice to make sure both are at a similar temperature.
Over- and Under-Attenuation
Along with fermentation, brewers are sure to acquaint themselves with the concept of attenuation. Attenuation refers to the yeast’s consumption of fermentable sugars in the wort and their transformation into carbon dioxide and alcohol. The attenuation process essentially thins out the beer. Beer can be rendered both under-attenuated (thick and sweet) or over-attenuated (thin and dry), depending on a number of factors.
Under-attenuation occurs when fermentation is not completed; this may be a yeast problem or it may be a brewer problem. Yeast that fails to complete fermentation may have been affected by residual sanitizer still in solution due to poor rinsing, by lack of dissolved oxygen in the wort, by cold temperatures, by extremely high or low pH levels in the wort, or the yeast itself may have been old and fatigued and incapable of multiplying in numbers great enough to complete fermentation. Also, certain liquid yeast strains are known to have low attenuation rates and may have to be roused during the fermentation cycle — consult the manufacturer’s data regarding yeast attenuation. Sometimes, for many of the same reasons mentioned above, fermentation may become “stuck” and the process slows way down or stops. Should this happen, the brewer should take immediate action. Typical remedies include agitating the yeast by shaking or stirring the wort (making sure that anything that comes in contact with the wort has been sanitized), moving the fermentation vessel to a warmer location, or adding more yeast or yeast nutrients to the wort.
The brewer may also be at fault for interrupting fermentation before it is complete. The results can be disastrous, from sweet, cloying beer to exploding bottles. This often happens when a brewer relies on “airlock watching” or “bubble counting.” Although vigorous fermentation may subside within a few days of pitching the yeast, an average-gravity brew should still be given a minimum 5- to 7-day primary fermentation, followed by an extended secondary fermentation in a separate vessel before bottling. Complete fermentation should always be verified with a hydrometer. (If the specific gravity reading remains constant for three days, you’re probably safe.) Malt sugars are approximately 70–80 percent fermentable by beer yeast, so by rule of thumb your beer’s final gravity reading should be about 20–30 percent or less of the original gravity reading.
Over-attenuation is a problem of a different sort. When over-attenuation occurs, your wort is left with very little residual sugar and the resulting beer is dry, tart and noticeably alcoholic. The causes of over-attenuation are many, from long, warm fermentations to alien bacterias. Over-attenuation can also be due to wild yeast, the so-called “super attenuators.”
If over-attenuation is a recurring problem in your beer, start with impeccable sanitation. If any uninvited bacteria are allowed to breed in your wort, they may consume a lot of the sugars not normally fermented by beer yeast. This will leave your beer considerably drier and “throat-warming” due to elevated alcohol levels. Make sure the temperature of the fermentation does not exceed 70° F (remember that fermentation itself is capable of raising wort temperature).
For most ales of average gravity, three weeks’ combined fermentation (primary and secondary) is sufficient time for the yeast to do its job. Allowing your beer to ferment and age beyond this length of time has diminishing effects on your beer (lagers not included). Unless your brew is a barleywine or similar high-gravity style, the longer it sits, the more likely it is to suffer even slight over-attenuation.
Yeast autolysis is a fermentation problem that goes beyond over-attenuation. It refers to the self-digestion of yeast cells by their own enzymes. This slow disintegration and breakdown of the cell membrane releases nitrogen into the wort. The effect of autolysis manifests itself in the aroma and flavor of the beer. At low levels it gives beer a “yeasty” smell and taste; at high levels it is experienced as a rubbery stench.
Since autolysis occurs when fermented beer is left sitting on a sedimented yeast bed for long periods of time, this problem can be avoided by bottling a beer at the appropriate time, or by racking the beer over to another vessel when bottling procedures must be delayed. Racking should be considered a short-term avoidance of the problem and not first-choice fix.
Judgment Day
So your beer has been in the bottle for two weeks and you’re dying to taste it. You chill a bottle, crack it open, pour it in your favorite beer glass and … hmmm, not quite you expected. What’s that funky smell? What’s that taste? Where’s the carbonation? This beer was supposed to be amber! What the $#@!! happened!?
Relax, you’re not the first homebrewer to blow a batch. But now is the time for reflective evaluation. Before corrections can be made, the problem needs to be properly identified. This calls for sharp senses (sight, smell, taste) and, where necessary, an appropriate vernacular to describe what you see, smell and taste. Fortunately for us brewers, one exists. For a quick guide, see the sidebar on page 39.
Over- or Under-Carbonated Beer and Poor Head Retention
Your beer is as flat as central Illinois or it gushes with the ferocity of a Yellowstone geyser. Carbonation, or the lack thereof, is clearly the problem.
Over-Carbonation. If you failed to properly sanitize your bottles, resident bacteria may have continued to gobble up the sugars that the beer yeast left behind, thus giving your beer an extra-heavy dose of fizz. If your beer was not fully fermented (see under-attenuation, above), most likely residual sugar was left in the brew. By adding priming sugar prior to bottling, you unwittingly created a small carbon-dioxide bomb. Even if your beer was fully fermented, adding too much priming sugar can create the same problem; make sure you use the appropriate amount of priming sugar for the volume of beer you are bottling.
Under-Carbonation. If you allowed your beer to ferment for an extended period of time, the vast majority of available sugars were likely consumed (see over-attenuation). Accordingly, the yeast in the beer dropped out of solution, sedimented, and fell back into a dormant state. If too few of these dozing yeast cells are still in your beer when you bottle it, it may take extra time for what little yeast remains to provide the requisite amount of carbon dioxide. Before blaming the yeast, however, double-check to make sure you used enough priming sugar. Furthermore, if you failed to properly rinse your bottles, residue from the sanitizer may have killed off the yeast, or at least kept them from doing their job. Temperature is also a consideration — allow your freshly bottled beer to condition at room temp for a week or two before refrigerating it.
Poor Head Retention. With regards to head retention in your beer, the problem may start with lack of carbonation. Without the minimum amount of CO2 in your beer, your beer may have difficulty mustering a frothy head. But even with plenty of carbonation, your beer may not sport a good rocky cap for long. This problem can be twofold: Either your beer is lacking in proteins that hold the head together and create the “Belgian lace” on the sides of your beer glass, or a contaminant is prematurely breaking down the head. Adding more proteins to your beer is a simple fix; head-building proteins come from grain, and wheat malt is an excellent source. Simply steep 1/2 pound of wheat malt in water and add it to your wort. Head-destroying contaminants may be in your beer or in your beer glass. Review cleaning and sanitizing techniques or inspect your glassware before using. Dust, lint, cleanser residue, body oils and lip balms may stunt an otherwise normal head. Autolyzed yeast is also a very potent foam killer.
Over- or Under-Bittered Beer
In all my years of evaluating beer, I recall very few instances when I noted too much malt content in a beer. More often than not, when a beer’s flavor leaned heavily in favor of the malt, it had more to do with the lack of hop balance than anything.
Hop bittering varies a great deal across the spectrum of beer styles and often requires a bit of finesse (good information also helps). Remember that bitterness from hops can be regulated in at least three different ways.
Hop variety. Each type comes with its own alpha acid (bittering) content, so choose wisely.
Hop quantity. Using more hops usually means getting more bitterness, depending on…
Hopping schedule. This refers to when the hops are added to the boiling beer. The longer hops are boiled, the more the alpha acids are dissolved (isomerized) in the brew; the less time hops are boiled, the less acid that is dissolved. Conversely, the less time hops are boiled, the less bitterness that is extracted and the more hop flavor and aroma is retained. The best hopping schedule addresses the bitterness, flavor and aroma of beer.
Three additional observations on under- and over-hopped beers. First, a beer that tastes over-hopped on the day it’s bottled may not seem as aggressive a month down the road. Hop bitterness tends to fade as a beer ages, so if you’re patient you may be pleasantly surprised. Secondly, pay as much attention to alpha-acid content as you do to hop variety when buying ingredients. Alpha-acid contents are not constant; they often change from one growing season to the next. Finally, untrained palates are quick to detect bitterness in beer, but are rarely able to identify its specific source. Hops are often blamed for bitterness that is actually grain-based astringency. If your low-hopped beer still tastes excessively sharp or bitter, you may want to review your grain bill, mill settings and mashing and sparging technique. Any or all of these variables may contribute a harsh, grainy or tannic bitterness to your beer.
Beer Clarity
To the average beer drinker, beer is supposed to be crystal clear. For the average homebrewer, expectations are different: Homebrew, by its nature, tends to be hazy. This haze is due to particulate matter still in suspension, most often yeast cells that are necessary for bottle conditioning. Even if you are unwilling to spend the time and money on filtering and carbonating equipment and procedures, there’s still hope for a clear beer. (For a complete rundown, see “How Clear is Your Beer” in the July-August issue of BYO.)
Clear beer starts with clear wort and clarifying the wort can be done in a number of ways. Start by adding an ounce of Irish moss to the brew in the last 15 minutes of the boil. This flaky dried seaweed, once re-hydrated, becomes a coagulant that causes proteins and other organic solids to clump together. These clumps will fall out of suspension with the help of gravity. Using Irish moss is especially effective in conjunction with “whirlpooling.” When the boil is done and the wort has been cooled, vigorously stir the wort in a circle. The resulting whirlpool will cause any particulate matter in the brewpot to collect in the relative calm in the center of the pot. By gently siphoning the cooled wort from the brewpot into a fermentation vessel, you can leave most of the hot break (precipitated proteins), grain silt and hop solids behind.
Clarification can also be done during secondary fermentation by adding a clarifying agent to the carboy; there are a couple of products available. Isinglass, gelatin, Polyclar and bentonite can all be mixed with water and added directly to the carboy. Simply follow package directions.
Occasionally, following the refrigeration of homebrew, a haze appears where before there was none. This is called “chill haze” and it’s caused by a drop in liquid temperature; chill haze usually appears around 36° F and disappears around 64° F. Since this temporary cloudiness is the result of precipitation of protein and tannin molecules during secondary fermentation, protein can be removed with Polyclar and tannin with silica gel.
Body and Mouthfeel
One thing I’ve found lacking in many homebrews is sufficient body and mouthfeel. Body refers to the thickness or viscosity of the beer and mouthfeel refers to its texture. This problem is especially prevalent in brews made from 100 percent malt extract. The fix is to add a pound of two of specialty grains, especially crystal malts.
Lack of body can be attributed to lack of dextrin, a bodybuilding component derived from grain. If your beers suffer from lack of body, mash a pound or two of dextrin malt with your base grain. Extract brewers can steep a pound or two of Carapils malt prior to boiling, or add a few ounces of malto-dextrin powder to the wort as it boils.
Mouthfeel is the term used to describe the tactile qualities of beer on your palate and in your throat. Texture is the part of this tactile quality (along with viscosity, carbonation, alcohol warmth, etc.) that is often attributed to the malt content, including specialty grains. Oats, flaked barley and roasted grains add a “chewy” quality to beer.
Finally, in the interest of improving your beer’s body and mouthfeel, reduce or remove any simple sugars that may be included in the recipe. Refined sugars such as dextrose (corn sugar) and sucrose (beet or cane sugar) are about 99 percent fermentable and rob your beer of body while adding little in the way of flavor. Limiting other flavoring sugars such as brown sugar, honey or maple syrup to 20 percent or less of the total amount of fermentable material in your beer is advised.
A Matter of Taste
Here are some terms to aid in beer evaluation techniques.
Acetaldehyde: Acetaldehyde can be identified by the smell or taste of green apples. Often this problem can be attributed to refined sugars, which, when fermented, taste cidery or tart. Disregard extract brewing instructions that call for refined sugar.
Astringency: Astringency is a “huskiness” or dryness from tannin in the grain husk. Tannin may be extracted from the grain in several ways: over-milling, high steeping or sparging temperatures (over 170° F) and high pH levels in mash and sparge water.
Diacetyl: Buttery or butterscotch aromas and flavors indicate diacetyl. Diacetyl occurs naturally during fermentation and it also naturally dissipates in a normal fermentation cycle. Obvious diacetyl character may indicate overly warm fermentation temperatures, unhealthy yeast, under-
oxygenated wort or contamination. Allow a “diacetyl rest” at the end of primary fermentation. Simply wait 2 to 3 days before racking to secondary, so the yeast can metabolize the diacetyl.
Enteric: An enteric is a bacterial contamination that makes beer smell like a soiled diaper! Sanitize, sanitize.
Fusel alcohol: Occasionally, a beer may have a hot or solventy flavor. This is due to fusel alcohol, which is produced at warm fermentation temperatures (above 75° F). It may smell and taste like paint thinner. Keep your fermentation temperature under 70° F.
Harshness: Some beers have a generic harshness; the sources can be varied. Over-hopping, especially when high-alpha hops are used, can often be the culprit. Beer made with hard (minerally) or chalky water can be blamed for harsh beer; if you can taste minerals in your water, consider buying distilled. Contaminated and over-carbonated beer may taste harsh and prickly. Review your sanitation and priming procedure.
Hydrogen Sulfide: Some sulfury odors emanate from the yeast, while others can be traced to bacteria. These odors can smell like rotten eggs or rubber. Move your beer through each stage of fermentation as is appropriate, and review sanitation procedures.
Oxidized: When wort or beer is exposed to oxygen it becomes oxidized, a condition that leads to premature staling. When mildly oxidized, beer can smell or taste papery; when heavily oxidized, beer can smell or taste like cardboard. Oxidized beer stored long-term takes on a sherry-like character. Minimize your beer’s exposure to oxygen, especially while the wort is still warm. Avoid splashing the wort or beer during racking and consider using oxygen-absorbing caps when bottling.
Phenol: This class of compounds is identified by aromas and flavors that seem medicinal or plastic. Most phenols are produced by wild yeast. Chlorophenol is a byproduct of chlorine, which suggests poor rinsing following bleach-sanitizing.
Sour or Tart: Spoilage bacteria often produce lactic or acetic acids which range from a mild grapefruit-like tartness to the mouthpuckering sourness of lemons or even vinegar. Assuming your beer is not one of the beer styles for which tartness is intentional (gueuze, lambic, Berliner Weiss), chances are it is irreparably damaged.
Vegetal: Vegetal aromas and flavors (cabbage, cauliflower) are the result of bacterial contamination during lag time. Dimethyl sulfide (DMS) is a compound whose aroma and flavor is associated with cooked or creamed corn. DMS originates in malt; when you boil the wort, DMS is created. Typically, DMS is driven out during the boiling process, but the hot wort can continue to create DMS even after the heat is turned off. So cool your wort quickly and minimize lag time. One note: Some DMS is part of the flavor profile of lagers, due to the fact that lager malts produce larger amounts of DMS.
Nyuk, nyuk, nyuk: That’s the unmistakable sound of a dimwitted doofus with a propensity for gumming up the works. Don’t be a stooge — practice good homebrewing habits!
