Troubleshooting Homebrew & Avoiding Common Mistakes

In the early years as a rookie homebrewer, there were many times where I poured myself a beer from a newly readied batch and said, “You know, this didn’t turn out quite how I expected.” Most of these variations were fairly minor and the beer was still quite good, just different than anticipated.

Admittedly there were a few batches where saying a few words over a case of bottles before letting them flow down the drain crossed my mind. This was obviously a last resort of course, as it takes a pretty bad beer to make me want to commit such a dastardly act.

As with anything in life, practice only makes you better equipped to prevent these surprises and allows your liquid masterpiece to more closely mimic your artistic vision. In the hopes of helping the less than expert brewer avoid some of the most troublesome issues I encountered way back when, I am here to share a handful of tips to ensure your path to brewing success is as smooth as a cask conditioned stout.

Problem: Inconsistent Original Gravities (OG)

Other than watching a beer that is stuck in fermentation purgatory, having your hydrometer settle in at 10 or 20 gravity points off what you thought it was going to be can be pretty frustrating. Some people may say that is just part of homebrewing, but so much of what we do is about control and I feel this subject deserves a fair amount of attention.

Dialing in the efficiency of your individual equipment takes time and can be very trying if you allow other variables to come into play. Having the right amount of extraction has a huge impact on how your beer will taste and its eventual alcohol level. This is more of an issue for all-grain brewers than for those of you that use mostly extracts, but it is good information to have if you ever want to make that leap of faith.

The first culprit that I identified for variation in original gravity was how the malt was getting milled. Sometimes I would mill it myself using a Corona mill or have it milled at one of my favorite homebrew suppliers. There was an obvious difference between doing it myself, and the various roller mills from the guys I bought my malt from. Different gap sizes in these devices can have an impact on how much starch gets extracted during the mash. You need to make sure your grains are getting crushed the same way each time you brew. If you have an issue with wheat or rye based beers coming in at low gravity, adjusting the mill for a finer grind may help as their kernels are a little smaller than barley.
It should also be noted that there are small variations in brewing grains that are from the same category, which could have a small impact on your wort gravity. Don’t expect all 2-row base malts (pale, pale ale, Pilsner, etc.) to perform the same.

Your water to grist ratio should also be consistent and not range too far outside the norm of 1.0 to 1.5 quarts per gallon (1 to 3 L/kg). Mash thickness has a direct impact on wort fermentability and extraction levels and should be tailored to beer style. Keep it the same when brewing a particular recipe multiple times, unless you are looking for different results. Mash and sparging temperature will also have an impact on how much carbohydrate is pulled from the grain, so keep an eye on that as well.

This may seem like a no brainer, but when you conduct the boil, be sure that the starting boil volume, boiling time and the heat source output are consistent each time you brew. Variations in these factors will either concentrate or dilute your wort.

One of the most exciting days as a homebrewer is when you get some new equipment to add to your arsenal. But when you upgrade from that little 3-gallon (11-L) pot on your stove to that Blichmann stainless steel 10-gallon (38-L) pot with a 50,000 BTU burner, there will be a big difference in how your wort turns out. Just be aware of that and consider your first batch on any new equipment as a test run, then adjust accordingly.

When it comes to measuring your OG, also be sure to follow the guidelines on your hydrometer in terms of temperature correction. It is always best to cool your wort down if possible to the baseline level when taking a reading. If you want the ability to make any adjustments to your wort’s gravity, I would suggest taking a reading with about 15 minutes left in your boil and add a small amount of malt extract or sugar to get it right if it looks like it will finish a bit low. If it’s on the high side, you can always boil a measured amount of water and add it to the kettle just before cooling (although this will dilute the hop character).

If you are like me and you are the type of person that likes to create their own recipes rather than follow the path of others, then you may only have to look in the mirror for your gravity woes. Being off on your calculations when formulating a recipe just a little bit can have a big impact on your OG. My recommendation is to make use of any of the great beer recipe programs out there. This will severely reduce the chance of human error and it’s a heck of a lot easier to boot!

Bottom Line: Consistency in all areas you have control over during the mash and the boil is key for an accurate original gravity.

Problem: All of Your Beers Have Signature Harshness

My very first batch of beer was supposed to mimic the flavors of Sierra Nevada’s Celebration Ale. It had all the right ingredients in terms of malt, hop varieties and yeast. But when I took that first sip, I noticed this taste that I couldn’t quite put my finger on. I just knew that whatever it was, it was the complete opposite of smooth. If you’ve entered your beer into a contest and have gotten a BJCP scoresheet back with the “astringent” box checked or comments about it having a strange/harsh bitterness, you know what I’m talking about. Let’s look at the potential causes for this all too common flaw.

Most of the reasons for why this undesirable flavor occurs can be found in the mash tun or boiling pot. The grain or extract itself is very rarely the problem unless you are only brewing really dark beers with copious amounts of roasted malts. If you are experiencing harshness across a large spectrum of beer styles, it is most likely your water that is to blame.

For all-grain recipes, you should try to keep your sparge water temperatures at a maximum of 170 °F (77 °C), especially near the end of wort collection, to avoid pulling excessive amounts of tannins from the husks. You also want to quit sparging before the pH of your runoff rises above 5.8 (or the specific gravity of the final runnings drops below 1.008).

The composition of your brewing water could have a number of factors working against you, so getting a water report is highly recommended if you think this could be the root of your problem. You should be able to get a copy of this information if you are on a municipal water supply. If you are on a well, you could have a sample analyzed at a lab for around $25-50.

Having this information is great, but you’ll need to know how to use it. Without diving too much into water chemistry, an excessive amount or lack of balance between any number of ions or compounds are common contributors to harsh flavors. I have personally done battle with very alkaline water carrying high levels of bicarbonates and way too much magnesium. My tap water was wreaking havoc on my beers for about a month until I figured out what the issue was. Water that has a high alkalinity keeps your mash pH high and is another way to extract harsh tannins from the grains. Treating the mash with brewing salts is one way to combat this, but only to a certain extent.

Other sources of harshness could be high levels of sulfate, calcium chloride and sodium. If you are looking for a quick solution to this problem, you could always dilute your water with bottled drinking water (which is what I did), use it entirely to brew with, or get a reverse osmosis (RO) system. If you choose to go the RO route, you may want to consider using brewing salts to add some calcium and other beer friendly ions back in to it.

Last but not least are the variety and amount of hops you are using. Most brewers believe that hops with high amounts of the alpha acid cohumulone contribute a more harsh bitterness than those with lower levels. Be sure you are not adding too much hops early on in the boil. If you are dry hopping a beer with pellets, you may also want to give it extra time to let the particles settle out or filter the beer with a sanitized, fine mesh bag before kegging or bottling. Those little hop pieces can be a little tough on the pallet.

Bitterness (a flavor) and astringency (a mouthfeel) are difficult to distinguish for some people and a problem with one can be compounded by a problem with the other. If your beers are “harsh,” examine everything in your brewing process that would affect either of these.

Bottom Line: Keep your temperature, pH and hopping rates in check and try using bottled water if you think your tap water is the problem.

Problem: Carbonation Too Lengthy and Variable

If you are bottling your beer and are frustrated with the turnaround time, I would highly recommend switching to kegs if you have the means to do it. It’s really not as hard as you think. All you have to do is get a CO2 tank, a pressure regulator, some food grade tubing, the proper connectors, a Corny keg, a refrigerator to put it in and a finger tap. Using physics to carbonate rather than relying on a biochemical reaction is much quicker and more exact. Using a carbonation chart, you can dial in the pressure and temperature to get the carbonation level you want in 7–10 days. Trust me, you’ll never go back once you do.

If that is still too long to wait and you are in a pinch to get some beer to your buddy’s bachelor party, there is another way. I’m not an advocate for the “crank and shake” method, but I’ve had good results with a slightly less crude version of this. Once your beer has been adequately cold conditioned at around 34–40 °F (1.1–4.4 °C), you could easily be sipping on it by that same afternoon by doing this without any adverse effects to the beer.

When filling your keg, be sure to leave about 10–15% head space. Connect the CO2 tank and purge the air out of it a couple times. Turn the pressure up to 20 PSI and lay the keg sideways on a flat surface with the CO2 connector facing up. Grab a chair a place it right in front of the keg. Gently rock the keg back and forth with your feet for about 10 minutes. Turn off the gas pressure at the regulator and place the keg in the refrigerator for a few hours. Come back and relieve the head pressure and then turn it to 1–2 PSI (if your serving tube isn’t more than a couple feet). I have used this method dozens of times and have never been disappointed. It hits the sweet spot of around 2.5 volumes of CO2, which is good for most ales. If you desire more or less carbonation, you can change the pressure setting or rock the keg for more or less time. You’ll get the hang of it.

Bottom Line: You don’t have to wait 2–3 weeks for complete carbonation of your beer if you don’t want to.

Problem: Accurately Predicting Perceived Bitterness

Have you ever had a pale ale that turns out more like an IPA? Or perhaps a brown ale that ends up tasting a bit Scottish? Any significant deviation from the intended bitterness of your recipe can completely change the eventual style of your beer even with all else being equal. In my opinion, the play between sweet and bitter is probably the most basic and critical factor in how your beer will end up tasting.

When we are just getting started creating recipes on your own, many of us think that outright estimated IBU’s will give us all we need to know, but that is only half the story. Right now the shelves at our favorite local stores carry bottles with various IBU ratings that are supposed to represent the level of iso-alpha acids in the beer that were contributed by various hop additions during brewing. Those numbers mean very little without knowing how much sweetness is left in the beer.

For example, if I told you a beer only had 20 IBUs, you’d think it wasn’t going to be bitter at all right? Well if that beer had a starting gravity of 1.025 and finished at 1.005, you might be singing a different tune after tasting it. The reason a 10% barleywine can have 60 IBUs and actually taste somewhat balanced is because there is a ton of residual sugars left behind.

I have found that the best indicator to use when putting a beer recipe together is the BU:GU ratio (where BU and GU stand for bitterness units and gravity units). All you have to do is take the estimated IBUs and divide them by the last few digits of the estimated OG like so: 40 IBU and 1.080 OG would be 40/80 or a 0.50 ratio. Most people would consider this to be a balanced beer. As you go above this number, the perceived bitterness increases with the opposite being true as you go lower.

I’m sure someone out there is wondering why the final gravity reading isn’t used in this formula instead. My guess is because the OG not only has a fairly direct correlation to the residual sugars, but also actually takes into account other flavor compounds yet to be produced by the yeast, which will be vying for influence over your taste buds along with the alpha-acids.

As mentioned earlier in this article, your water could also have something to contribute to bitterness in addition to any highly-kilned malts you’ve got in your grain bill. There’s no numerical way to measure their affect on your beers flavor or an individuals personal sensitivity to iso-alpha acids for that matter. That being said, the BU:GU ratio will get you on the right track to having better control over what you eventually taste and your own recipes as a whole.

Bottom Line: Bitterness is a function not only of the number of IBUs, but of what else is in your beer. This includes the grain bill and water chemistry.

Problem: Stuck Fermentation or High Final Gravity (FG)

Almost every homebrewer has faced this situation. Your fermentation has slowed to a stop. You go to take a hydrometer reading and it is way too high. You spin the hydrometer to dislodge any bubbles clinging to the glass, but the reading doesn’t change. What went wrong (and can it be fixed)?
An overly high final gravity can have several negative impacts on your beer. First, the beer will likely be too sweet, compared to what you expect. In addition, residual sugars left behind could become a food source for contaminating bacteria.

So where do you start when your fermentation has stopped too soon. The first thing you should do is to double check your expectations — what final gravity (FG) did you expect to reach and why?
For most homebrews, the expected apparent attenuation (the degree of attenuation you measure with your hydrometer) is around 75%. Yeast suppliers will give the range of apparent attenuations for each yeast strain, but the 75% figure is worthwhile to remember for quick reality checks. If you think your FG is too high, take the OG (in “gravity points”) and divide by 4 to get an estimated FG. (For example, if your OG was 1.080, your expected FG would be 1.020, because 80 divided by 4 is 20.) There are many factors that influence your FG, so the above is just a quick check that works best for all-malt beers that aren’t brewed to be overly sweet or overly dry. Sometimes homebrewers are expecting an FG lower than is realistic, especially those new to brewing beers that start at a high OG.

If you consistently deal with higher than expected FGs, you can get an accurate idea of what your final gravity should be by performing a forced wort test. On brew day, take a small sample of your chilled wort (perhaps in a small jar), aerate it well and pitch an abundance of yeast (many times your actual pitching rate). Keep the sample warm (preferably around 80 °F/27 °C) until fermentation stops, then take a hydrometer reading.

This reading — from “overpitched,” well-aerated wort, fermented warm — will tell you days ahead of time what your actual FG should be. If the FG of your full batch of beer is higher, you have an actual problem with your fermentation.

Another thing to check is the accuracy of your hydrometer. If your hydrometer were reading high, your beer would be fine, but the measurement would be off. For starters, do a quick calibration by floating your hydrometer in water. In pure water, it should read 1.000 — and even in most tap waters, the deviation due to dissolved minerals would be negligible. If you think your hydrometer is reading wrong, you will need to calibrate it.

If you think that you are consistently getting great extract efficiency (from your high OG readings), but poor attenuation (from the FG readings), yet your beer does not taste inappropriately sweet, your hydrometer is a likely culprit.

But what if your expectations are realistic and your hydrometer is accurate? In other words, what if something is actually wrong and your fermentation stopped short?

The reason that stuck fermentations are common in homebrewing is that there are many different factors that lead to them. In some cases, the fermentation can easily be restarted; in others, there is no easy remedy.

One reason that some fermentations stick is that the temperature in the fermenter drops too low. This is the easiest type of stuck fermentation to fix. Simply stir the yeast back into suspension (without aerating the wort) and warm the fermentation up. This can be done by moving buckets or carboys to warmer locations or with a heating blanket. Fermentations stopped by the cold can almost always be restarted when a proper temperature is re-established.

Another reason fermentations can stick is due to poor yeast performance, and there are many causes of this. If your wort was lacking in nutrients, not sufficiently aerated prior to pitching or you pitched an inadequate amount of yeast, they can perform sluggishly and stop fermenting early. And unfortunately, most often this cannot be corrected after the fact. Adding yeast nutrients when a fermentation is mostly completed may revive the yeast, but residual nutrients will leave you with very biologically unstable beer. Likewise, adding oxygen to mostly fermented beer will definitely reinvigorate the yeast, but it will also cause them to excrete an excessive amount of diacetyl into your beer. It will also accelerate staling.

In these cases, you may be able to salvage the beer by making a yeast starter and repitching some healthy yeast to the batch. If you try this, do not aerate the main batch or add yeast nutrients. For a 5-gallon (19-L) batch, make a 1⁄2-quart (1⁄2-L) starter, aerate well and pitch it at high kräusen.
You should know, however, that this procedure is not guaranteed to work. When yeast are stressed, they secrete certain proteins into their environment that suppress growth. So, if you try to revive a stressed fermentation by adding active yeast, they may simply shut down when they encounter the “stress proteins” in the wort. If you are really determined to rescue a batch, you can fine the beer with something that removes proteins (such as silica gel), and then try repitching with fresh, actively-fermenting yeast.

In all of the above cases — inadequate nutrition, underaeration and underpitching — it is much easier to take care of the potential problem on brew day than to try to compensate for it later. And remember, you can add yeast nutrients to your yeast starter as well as giving the starter periodic shots of oxygen.

A final potential cause for an overly high final gravity may be the fermentability of your wort. Some worts may contain an overabundance of non-fermentable carbohydrates. Even with an adequate amount of nutrients, oxygen and yeast cells, the fermentation will stop when all of the fermentable sugars are gone. The non-fermentables may come from large additions of some malt extracts, lactose or crystal malts, or they could result from a “short, high” mash (a mash where the saccharification rest temperature was at the high end of the range and the overall duration was short).

There is a possible remedy to this problem, but it is tricky. You can add Beano® (the dietary supplement that helps people digest beans more agreeably) to your beer and convert some of the non-fermentable carbohydrates to fermentable sugars. However, there is no way to know how much Beano® to add. Beano® is an enzyme and keeps working until it breaks down. There is no formula for how much of this to add because its action is unpredictable. Hombrewers who have tried this frequently report that overly sweet batches of beer were transformed into “rocket fuel” — dry, highly alcoholic tasting beverages.

Bottom Line: A stuck fermentation or overly high FG are two of the most common problems in homebrewing. There are many possible causes for this and in every case it is easier to avoid the problem by using proper brewing techniques than to remedy the situation afterwards.

Problem: Overly Dark Extract Beers

Brewing using malt extract is a convenient way to brew and most popular beer styles can be made using extract. One of the biggest problems extract brewers face, however, is beers that turn out darker than expected.

There are basically three reasons that extract beers sometimes have too much color — stale extract, scorching or Maillard reactions.

Malt extract is a food product made from grains and, as with anything made from grains, it will eventually go stale. When it does so, its color darkens. Since liquid malt extract contains water, it goes stale more quickly than dried malt extract. As such, if you use liquid malt extract, find a source that gets it fresh and use the extract within a couple months. Dried extract will store longer, but is not immune from staling (especially if it is not stored in an airtight container).

When brewing with extracts, it is easy for clumps of incompletely dissolved extract to fall to the bottom of your brewpot. There, with a thick sugary solution next to the hot metal surface, malt sugars will caramelize (a reaction between sugars) and scorch. Whenever stirring malt extract into your brewpot, turn off the heat briefly. Also, continue stirring longer than you think is necessary before turning the heat back on.

Extract brewing frequently involves making very thick worts in your brewpot, then diluting them to working strength in the fermenter. Unfortunately, at higher concentrations of wort solids, reactions between sugars and amino acids (Maillard reactions) are more favored and these reactions will darken a wort. If you can’t boil your full wort volume, try adding as much of the malt extract as is feasible late in the boil (for the final 5–15 minutes). Malt extract does not need to be boiled for longer than the amount of time it takes to sanitize it.

Finally, extract brewers should also know that malt extract makes wort that is slightly darker than the equivalent wort made from grains. This is because malt extract picks up some color as it is concentrated. For all but the lightest beers, you can adjust the darkest specialty grains downward a bit, if color matters to you.

Bottom Line: Use fresh malt extract, stir well and minimize the amount of time you boil the wort when it is at its thickest (i.e. add the extract late).

Problems & Causes

Key: “X”: For beers made with malt extract, “AG”: For all-grain beers

Fermentation does not start

• Inadequate amount of yeast pitched
• Wort too hot (yeast stunned/killed)
• Wort too cold (yeast dormant)
• Fermentation fine, but bucket not sealed (so you can’t see bubbles in airlock)
• Fermentation already complete (look for ring of “crud” around inside of fermenter)

Stuck fermentation

• Not enough yeast pitched
• Inadequate aeration
• Wort temperature too low
• Yeast strain flocculated early (rousing yeast may help)
• Fermentation is finished, not stuck (take specific gravity to check)

A puckering, tea-like quality; sometimes confused with bitterness (astringency)

• X: steeped grains in too much water (over 3 quarts water per pound of grain)
• X: steeping water too hot (over 170 °F)
• AG: excessive volume of sparge water (collected wort less than SG 1.008 or above a pH of 5.8)
• AG: excessively hot sparge water (over 170 °F)

Sour or tart beer

• Contamination
• Tart ingredients (like raspberries or cranberries)
• AG: mash sat overnight and temperature dropped to 120 °F (or below)

A buttery or butterscotch-like flavor or aroma (diacetyl)

• Yeast did not absorb diacetyl (a diacetyl rest is required for some lager yeast strains)
• Contamination
• Racked beer too early
• Yeast strain

Overly fruity aromas, especially banana (estery)

• High fermentation temperatures
• Inadequate pitching rate
• Yeast strain (some British and Belgian ale strains are supposed to be very fruity)

Chloraseptic-like or Band-aid-like aroma or flavor (phenolic)

• Contamination

Vinegar flavor or aroma (acetic)

• Contamination, especially in conjunction with exposure to oxygen

Wort darker than expected

• X: concentrated wort boil
• X: scorching of malt extract (stir in thoroughly)

Stuck mash

• Running off wort too quickly
• Grains crushed too finely
• High percentage of wheat or rye

Low extract efficiency

• Crush too coarse
• Collecting wort too fast
• Collecting too little volume of wort per unit of grain • Poor lauter tun design
• Water chemistry not conducive to good mash (check calcium levels first)
• pH outside of 5.2-5.6 range

Overly high final gravity (FG)

• Maybe the beer was supposed to have a high FG
• High percentage of specialty malt in recipe
• Yeast strain
• Any of causes listed under “stuck fermentation” on page 42

Chill haze

• Use Irish moss (at rate of 1 tsp. per 5 gallons)
• Boil too short or not vigorous enough

Poor foam

• Glassware dirty
• Weak fermentation
• Too little protein in wort (esp. when high amounts of adjunct are used)
• AG: overly-long rest at 122-131 °F

Mold on surface of beer

• It may be yeast, not mold (different yeast strains behave differently)
• Wort is exposed to oxygen, which encourages surface growths

Bottle-conditioned beer is flat

• Move bottles to warmer location for conditioning
• Give beer more time to condition
• Beer and priming sugar not adequately mixed in bottling bucket
• You forgot the priming sugar
• Not enough yeast left in beer to bottle condition (rarely happens)

Bottle-conditioned beer is overcarbonated

• Contamination
• Beer and priming sugar not adequately mixed in bottling bucket
• Too much priming sugar

Beer’s original gravity (OG) too low

• X: wort and topping up water not mixed thoroughly
• AG: poor extract efficiency

Cheesy aroma or flavor

• Hops are old and stale

Corn-like aroma or flavor (DMS)

• Wort cooled too slowly when certain very pale malts used
• Contamination

Solvent-like or nail polish aromas

• Fermentation temperature too high (higher alcohols, fusel oils)• Inadequate aeration
• High original gravity

Skunk-like aroma

• Beer exposed to light (especially due to bottling in clear or green bottles)

Wet cardboard aromas and flavors (oxidation)

• Beer exposed to oxygen during late fermentation or conditioning

Sherry-like aromas or flavor (oxidation)

• Beer exposed to oxygen during late fermentation or conditioning
• Long aging of high-alcohol beers (appropriate in some cases)

Excessive sediment in bottle conditioned beer

• Some sediment is always present
• Let beer fall clear before bottling

Water, wort or beer on floor

• Be sure all valves are closed before transferring liquid to a vessel

Beer on ceiling

• Fermentation lock clogged (use blow-off tube next time)

Issue: September 2012