Brewing FAQs

Whites Party Store Homebrewing FAQs

How do I get started with Homebrewing?

The first thing I’d recommend is to pick up a good book and start to read about the process. It’s best if you go into it with a little bit of knowledge about what kind of equipment you should buy and the different ways you can go about brewing your recipes. Charlie Papazian’s “The Joy of Homebrewing” is a great book to get you excited about brewing. It takes the approach of keeping brewing fun and isn’t to technical.

Another great read is John Palmer’s “How to Brew”. I think this is one of the most valuable resources a homebrewer could own. You can actually read the book for free on his website It covers almost every topic there is when it comes to learning how to brew beer. I have been a homebrewer for 13+ years and I still use this book quite regularly.

The next thing you will need to do is get set up with a starter kit. Most of these do not come with a boil kettle. A 7 gallon kettle is ideal to do 5 gallon batches of beer. A lot of people use a smaller pot to start with because kettles are expensive. If you don’t want to spring for a large kettle right away, be sure to find one big enough that will allow you to at least boil half of the volume of your batch. You can top up with water once in the fermenter.

Full boil vs Partial boil?

If you have the ability to do a full boil, go for it. It is the optimal way to do it. If you don’t have a kettle that will allow you to do a full boil you will have a few issues to work through.

  • Your hop utilization will be lower due to the increased starting gravity of your beer.
  • Your beer may finish a bit darker than intended because of an increase in Maillard reaction that occurs in higher viscosity worts.

Solutions: One option to take care of your hop utilization is to simply use more hops. There are many online recipe calculators that will tell exactly how much to add once you plug in your boil size. Another option is to only add half of your Malt Extract to your boil kettle to keep your gravity down. You would just add the second half of the extract with 15 minutes left in the boil.

Stuck Fermentation, what should I do?

This happens from time to time for a number of reasons. Things that can cause a fermentation to stop: Temperature swings, unhealthy yeast, alcohol tolerance (to much alcohol for the yeast to handle), not enough yeast for the amount of fermentables.

The first thing you should do is take a hydrometer reading at 60F and get an accurate gravity reading. If you know some things about your yeast like what sort of attenuation it has or what temp does it perform best at – that can help too.

Some yeast don’t attenuate as much as others. Attenuation is just the percentage of sugar that is eaten by the yeast. If you have a beer that starts at a gravity of 1.100 and finishes at 1.025 then you know your attenuation is 75%. Most yeast provide this info on the packaging or on their website.

Yeast also likes for the temperature to remain consistent or slowly ramping up in temp. When fermentation temps drop all of a sudden, it is a shock to the yeast and they can stop performing and flocculate out. Making a yeast starter is a good way to make sure that you have enough yeast for higher gravity beers. Ideally a yeast starter is make with wort with an O.G. of 1.040. Do NOT make a yeast starter in high gravity wort to prepare it for a high gravity fermentation. This just stresses the yeast out and you end up starting with a beat up batch of yeast.

If you find your fermentation has come to a halt prematurely and you have a hydrometer reading that shows that you should still have some fermentable sugar left given the attenuation range of your yeast strain, you should make sure that your fermenter is someplace that is around 70F and see if warming it up helps. You can gently try and rouse some yeast from the bottom by gently swirling the fermenter but you want to do this carefully and try not to aerate the wort too much. If still you see no activity some yeast nutrient and additional yeast may be needed. Most times it is hard to get activity going again. Pitching fresh yeast into a stuck beer is taxing on the new yeast because of the low gravity and alcohol presence. A lot of people like to use a Champagne yeast due to its high alcohol tolerance and good attenuation.

Added yeast but no signs of Fermentation.

This seems to be a common problem with new brewers. Usually this is caused when yeast is added before the wort is cooled down to the proper temperature. If you pitch your yeast while it is still too hot you will kill your yeast and fermentation won’t start. It is best to cool your wort down to about 68-70F. Remember that once fermentation starts the temp will rise in your fermenter by a couple of degrees do to the exothermic qualities of the yeast. When yeast is added to the wort it takes some time to acclimate to its new environment. It is gearing up to get started with fermentation but during this time (lag phase) there is no apparent activity going on. Usually you will start to see activity around 24 hours but sometimes it can take closer to 48-72 hrs. If it is taking longer than that than there may be some other issues.

If you are planning on using a yeast (liquid) that has been sitting around for a long time, you may need to make a yeast starter to rejuvenate it. There is no point in making a yeast starter if you are using dry yeast. It is not that expensive to just buy an extra packet of dry yeast where as it is cost prohibitive to do that with liquid yeast strains. Pitching yeast that is old can also cause a lack of activity in the fermenter.

What kind of cleaner/sanitizer should I use?

It is important to realize that there is a difference between sanitizer and cleaning agents that you use to do the initial cleaning. When you have equipment that has lots of visible gunk like a fermentation bucket, it is best to get as much of that stuff off using hot water and a non-abrasive rag so you don’t put scratches in your buckets. Once most of the visible matter is gone, using a product like PBW works great to get it really clean. It has to be CLEAN before it can be SANITIZED. Once it is clean you can use an iodophor solution or StarSan for your sanitizing step. There are other products available on the market too. Just make sure you know whether it can be used cleaning, sanitizing or both. Also be sure to follow the guidelines listed on products like: “rinse or no rinse”, contact times, dilution ratios etc.

What kind of hops should I use and how much?

There are so many hop varieties available to homebrewers it is hard to decide on which ones you should use. Truth be told, it comes down to a mixture of knowing what types of hops are found in different beer styles as well as just using some of your own creativity. The best place to find info on this would be the BJCP (Beer Judge Certification Program) website. They give in depth descriptions of all of the beer styles aside from those beers that just really don’t fall into any category. They provide information on what types of hops you might typically find in a certain style and they also give ranges for acceptable IBUs (International Bittering Units) for each style. This comes in really handy if you know what style of beer you want to make. And if you are using some form of a recipe calculator you can really dial in your hops to fit your beer just right. A lot of this knowledge just comes from reading and trying different hops to see what you like and don’t like.

How do I know how much hops I should use if I am substituting for an unavailable variety?

Substituting one hop variety for another isn’t always as easy as just using 1oz of “this” for 1oz of “that”. Hops usually come labeled with their own specific AA Units or Alpha Acid units. AA units are indicative of the bittering potential of that hop when the oils have been fully broken down in the boil. For example if you wanted to substitute an ounce of Cascade that has an AA Unit of 6% for an ounce of a higher Alpha hop that has an Alpha Acid unit of 12%, you would need to use twice as much in order to get the same bittering quality.

Figuring out your hops without any brewing software.

Yes, it can be done. Bust out your calculator.

Hop Bittering Calculations –John Palmer “How to Brew”

For those of you who dislike math, I will make this as straightforward as possible. We will use the following example:

Example Ale
6 lbs. of Amber DME
1.5 oz of 6.4% AA Perle hops (60 minutes)
1 oz of 4.6% AA Liberty hops (15 minutes)

For a 5 gallon recipe, we will boil 1.5 oz of Perle hops for 60 minutes for Bittering and 1 oz of Liberty for 15 minutes for Finishing. The recipe calls for 6 lbs. of dry malt extract and it will be boiled in 3 gallons of water because of the pot size. The remaining water will be added in the fermenter.

The first step is to calculate the Alpha Acid Units (AAUs).
AAU = Weight (oz) x % Alpha Acids (whole number)
AAU (60) = 1.5 oz x 6.4 = 9.6 AAUs of Perle and AAU (15) = 1 oz x 4.6 = 4.6 AAUs of Liberty

Whenever a brewer is using AAUs in a recipe to describe the quantity of hops, it is important to specify how long each addition is boiled. The boiling time has the largest influence on how bitter a hop addition makes the beer. If no times are specified, then the rule of thumb is that bittering hops are boiled for an hour and finishing hops are boiled for the last 10-15 minutes. Many brewers add hops at 15 or 20 minute intervals and usually in multiples of a half ounce (for ease of measurement).

To calculate how much bitterness the final beer will have from these hop additions, we apply factors for the recipe volume (V), gravity of the boil and the boil time. The time and gravity of the boil are expressed as the utilization (U). The equation for IBUs is:
IBU = AAU x U x 75 / V

75 is a constant for the conversion of English units to Metric. The proper units for IBUs are milligrams per liter, so to convert from ounces per gallon a conversion factor of 75 (74.89) is needed. For the metric world, using grams and liters, the factor is 10. (For those of you paying attention to the units, the missing factor of 100 was taken up by the % in the AAU calculation.)

Gravity of the Boil

The recipe volume is 5 gallons. The gravity is figured by examining the amount and concentration of malt being used. As noted in the previous chapter, dry malt extract typically yields about 40 pts/lb./gal. Since this recipe calls for 6 lbs. of extract to be used in 5 gallons, the calculated OG = 6 x 40 / 5 = 48 or 1.048

But, since we are only boiling 3 of the 5 gallons due to of the size of the pot, we need to take into account the higher gravity of the boil. The boil gravity becomes 6 x 40 / 3 = 80 or 1.080

It is the gravity of the boil (1.080) that is used in figuring the Utilization. As you will see in the next section, hop utilization decreases with increasing wort gravity. The higher concentration of sugars makes it more difficult for the isomerized alpha acids to dissolve. I use the initial boil gravity in my utilization calculation; others have suggested that the average boil gravity should be used. (The average being a function of how much volume will be boiled away during the boiling time.) This gets rather complicated with multiple additions, so I just use the initial boil gravity to be conservative. The difference is small—overestimating the total bitterness by 1-3 IBUs.


The utilization is the most important factor. This number describes the efficiency of the isomerization of the alpha acids as a function of time. This is where a lot of experimentation is being conducted to get a better idea of how much of the hops are actually being isomerized during the boil. The utilization numbers that Tinseth published are shown in Table 7. To find the utilizations for boil gravities in-between the values given, simply interpolate the value based on the numbers for the bounding gravities at the given time.

For example, to calculate the utilization for a boil gravity of 1.057 at 30 minutes, look at the utilization values for 1.050 and 1.060. These are .177 and .162, respectively. There is a difference of 15 between the two, and 7/10ths of the difference is about 11, so the adjusted utilization for 1.057 would be .177 – .011 = 0.166.

The Utilizations for 60 minutes and 15 minutes at a Boil Gravity of 1.080 are 0.176 and .087, respectively. Inserting these values into the IBU equations gives:
IBU(60) = 9.6 x .176 x 75 / 5 = 25 (rounded to nearest whole number) and
IBU(15) = 4.6 x .087 x 75 / 5 = 6
Giving a grand total of 31 IBUs.

Chart for Utilization as a function of Boil Gravity and Time

Utilization numbers are really an approximation. Each brew is unique; the variables for individual conditions, i.e. vigor of the boil, wort chemistry, or for losses during fermentation, are just too hard to get a handle on from the meager amount of published data available. Then why do we bother, you ask? Because if we are all working from the same model and using roughly the same numbers, then we will all be in the same ballpark and can compare our beers without too much error. Plus, when the actual IBUs are measured in the lab, these models are shown to be pretty close.

Buckets vs. Carboys – John Palmer “How to Brew”

There are two types of fermenter commonly available: food grade plastic buckets (bins) and glass carboys. Each type has its own merits. The plastic buckets are slightly less expensive than the glass and much safer to handle. The buckets have the outstanding option of being fitted with spigots, which makes siphoning unnecessary; a real plus. The buckets are typically 6 gallons, giving 1 gallon of headspace for the fermentation, which is usually sufficient.

The spigot option eliminates siphoning and is practically a necessity at bottling time. A bottling bucket with a spigot allows greater control of the fill level. In my opinion, this is the only way to bottle.

Although you will need a siphon, glass has the advantage of letting you see your beer and be able to gauge the activity of the fermentation. There are two sizes commonly available, a 6 1/2 gallon size that is perfect for primary fermentations and a smaller 5 gallon size which is ideal for secondary fermentation. The large size typically has enough headspace to contain the krausen, while the 5 gallon size almost completely eliminates the headspace above the beer, preventing oxidation during the conditioning phase. You will need to shield the carboys from the light, but you can easily tell when fermentation is over and the yeast is settling out.

Airlocks vs. Blowoffs – John Palmer “How to Brew”

The decision to use an airlock or blowoff hose is determined by headspace. Usually the buckets and large carboys have enough headspace (at least 3 inches) that the foam does not enter the airlock. If the fermentation is so vigorous that the foam pops the airlock out of the lid, just rinse it out with sanitizer solution and wipe off the lid before replacing it. Contamination is not a big problem during the primary phase. With so much coming out of the fermenter, not much gets in. If the fermentation keeps filling the airlock with crud and popping it out, there is an alternative.

The alternative is called a blowoff hose and it allows foam and hop remnants to be carried out of the fermenter. A blowoff is a necessity if you are using a 5 gallon carboy as your main fermenter. Get a 1 inch diameter plastic hose and fit this snugly inside the mouth in the carboy or enlarge the hole in the bucket lid if necessary. Run the hose down the side and submerge the end in a bucket of sanitizer/water. It is important to use a large diameter hose to prevent clogging. If the tube gets clogged, the fermenter can get pressurized and blow goo all over the ceiling, or worse – burst.

Fermentation temperatures

Normal ale fermentation temperatures range from 68 to 72 °F (20 to 22 °C) and lager fermentation temperatures from 45 to 55 °F (7 to 13 °C). Also keep in mind that the heat generated by an active fermentation can warm a typical 5-gallon (19-L) batch of beer by 10 to 15 degrees Fahrenheit (5.5 to 8.3 degrees Celsius). Even though a basement in a northern climate may be cool enough to keep ale fermentation from overheating, it is often not cool enough to properly conduct lager fermentation. On the other hand, fermenting below the normal temperature range for a given yeast strain may result in a sluggish or incomplete fermentation.

Aeration is Good, Oxidation is Bad – John Palmer “How to Brew”

The yeast is the most significant factor in determining the quality of a fermentation. Oxygen can be the most significant factor in determining the quality of the yeast. Oxygen is both your friend and your enemy. It is important to understand when which is which.

You should not aerate when the wort is hot, or even warm. Aeration of hot wort will cause the oxygen to chemically bind to various wort compounds. Over time, these compounds will break down, freeing atomic oxygen back into the beer where it can oxidize the alcohols and hop compounds producing off-flavors and aromas like wet cardboard or sherry-like flavors. The generally accepted temperature cutoff for preventing hot wort oxidation is 80°F.

Oxidation of your wort can happen in several ways. The first is by splashing or aerating the wort while it is hot. Other beginning-brewing books advocate pouring the hot wort after the boil into cold water in the fermenter to cool it and add oxygen for the yeast. Unfortunately the wort may still be hot enough to oxidize when it picks up oxygen from the splashing. Pouring it down the side of the bucket to minimize splashing doesn’t really help either since this increases the surface area of the wort exposed to the air. Thus it is important to cool the wort rapidly to below 80°F to prevent oxidation, and then aerate it to provide the dissolved oxygen that the yeast need. Cooling rapidly between 90 and 140°F is important because this temperature region is ideal for bacterial growth to establish itself in the wort.

In addition, if oxygen is introduced after primary fermentation has started, it may cause the yeast to produce more of the early fermentation byproducts, like diacetyl. However, some strains of yeast respond very well to “open” fermentations (where the fermenter is open to the air) without producing off-flavors. But even for those yeast strains, aeration or even exposure to oxygen after fermentation is complete can lead to staling of the beer. During racking to a secondary fermenter or to the bottling bucket, it is very important to prevent gurgling or splashing. Keep the siphon flowing smoothly by placing the outlet of the siphon hose below the surface of the rising beer. Decrease the difference in height between the two containers when you begin. This will slow the siphon rate at first and prevent turbulence and aeration until the outlet is beneath the surface.

To summarize, you want to pitch a sufficient amount of healthy yeast, preferably grown in a starter that matches your intended fermentation conditions. You want to cool the wort to fermentation temperature and then aerate the wort to provide the oxygen that the yeast need to grow and reproduce. Then you want to protect the beer from oxygen once the fermentation is complete to prevent oxidation and staling.

Does it matter what kind of bottles are used for bottling?

Not all bottles are created equal. Be sure that when you are rounding up bottles to use for your homebrew that you only use bottles that are meant to take pry-off caps and not twist offs. I’ve seen beers that are threaded that have pry-off caps on them and sadly the beer inside is usually flat due to not being able to keep a tight seal. Flip-top bottles are nice to use because they save a lot of time and you don’t have to worry about purchasing caps. You do, however, have to make sure that the rubber gaskets are replaced from time to time as they wear out and may not keep a good seal.

Another thing to keep in mind when bottling is the amount of CO2 you are planning to achieve. If you are bottling a Belgian-style ale that typically has a higher amount of carbonation, you will want to make sure that you are using bottles that can hold up to that sort of pressure. You will notice that some bottles feel light in the hand while others have substantial weight to them. Exploding bottles can be dangerous so always use the right kind of bottle for the beer you are packaging.

Can I use any old plastic buckets for brewing?

No, You must use a food grade plastic for brewing. You can find them at your LHBS or online on any of the online homebrew supply stores. If you come across buckets that you are unsure of you can look on the bottom to see if there is any indicator of it being food grade plastic. Also be sure to inspect the inside of the bucket for scratches or any off odors. Do NOT use old pickle buckets for brewing. Even though they are food grade, they will most likely still have a strong pickle smell to them that will inevitably show up in your beer as well.

Carbonation issues:

Too much or not enough. Inconsistent-what happened?

Not Enough Carbonation can be caused by:

Not enough priming sugar.

This is not as common as over-carbonation but it does happen. Before carbonating your beer be sure to have a target volume of CO2 in mind. This will be very important when deciding on how much sugar to add. Not all beers should be primed the same, and not all sugars have the same fermentability. There are plenty of CO2 Calculators on the web. If you are using DME (Dry Malt Extract) as your source of sugar for priming, you will have to add more than if you are using Corn or Cane sugar. Malt Extract has a lower fermentability than regular sugar. Be sure to put the correct form of sugar into your CO2 Calculator.

Style & Volumes of CO2

  • American ales 2.2–3.0
  • British ales 1.5–2.2
  • German weizens 2.8–5.1
  • Belgian ales 2.0–4.5

  • European Lagers 2.4–2.6

  • American Lagers 2.5–2.8

Not enough yeast in suspension to eat priming sugar.

If you make a high gravity beer that needs to sit in a secondary fermentor for a long period of time like a Russian Imperial Stout or Barley Wine, you will probably want to add a little bit of fresh yeast to your beer right before bottling time. When beer sits for a long time the yeast will settle out and there may not be enough viable yeast in suspension to carbonate the beer. You may also want to do this with high gravity beers because the yeast has already taken a beating from having to chew through all of the fermentables in the beer. You will only need to pitch a small amount of sugar. A gram or two of a dry yeast should be plenty to handle a 5 gallon batch.

Storage Temperature

After you have bottled your beer it should be kept at room temp for about two weeks or until you have reached a sufficient carbonation level in your beer. Then you may store it cold if you’d like. If it is stored cold right after bottling, you will not achieve the desired carbonation levels.

Too much carbonation is caused by:

Too much sugar

Simply, too much carbonation is caused by adding too much priming sugar. Sometimes people assume that they are dealing with a full 5 gallons of beer and really it is less than that due to losses from transfer or blow-off in the fermenter. Racking beer into a bottling bucket with graduated volume markers is a good way to see exactly how much product you have to carbonate.

Inconsistent carbonation is caused by:

Stratification of sugar in the beer

Sometimes people will run into the problem where they will have some bottles that have lots of CO2 and others that are lacking. When adding priming sugar to your beer it is really important to make sure that the sugar is mixed in well. This is tricky because you want to mix it gently as not to aerate the beer but you need to mix it well enough to make sure the sugar is dispersed equally throughout the beer without stratification. Gently stirring the beer a little from time to time while bottling is helpful in preventing stratification as well. If you are looking for a quick and easy way to prime your beer, there are carbonation drops that you can add to your bottles that look like little candies. They are basically just sugar that dissolves and provides your yeast with the sugar it needs. The downside to these drops is that it may or may not be the ideal amount of sugar for the beer that you brewed as not all beers should be carbonated the same.

Is My Beer Ruined? Off Flavors in Beer


A flavor of green apples or freshly cut pumpkin; it is an intermediate compound in the formation of alcohol. Some yeast strains produce more than others, but generally it’s presence indicates that the beer is too young and needs more time to condition.


A sharp flavor that can be mild and pleasant or hot and bothersome. When an alcohol taste detracts from a beer’s flavor it can usually be traced to one of two causes. The first problem is often too high a fermentation temperature. At temperatures above 80°F, yeast can produce too much of the higher weight fusel alcohols which have lower taste thresholds than ethanol. These alcohols taste harsh to the tongue, not as bad as cheap tequila, but bad nonetheless.

Fusel alcohols can be produced by excessive amounts of yeast, or when the yeast sits too long on the trub. This is one reason to move the beer off of the hot and cold break when the beer is going to be spending a lot of time in the fermentor.


Astringency differs from bitterness by having a puckering quality, like sucking on a tea bag. It is dry, kind of powdery and is often the result of steeping grains too long or when the pH of the mash exceeds the range of 5.2 – 5.6. Oversparging the mash or using water that is too hot are common causes for exceeding the mash pH range. It can also be caused by over-hopping during either the bittering or finishing stages. Bacterial infections can also cause astringency, i.e. vinegar tones from aceto bacteria.
The brown scum that forms during fermentation and clings to the side of the fermentor is intensely bitter and if it is stirred back into the beer it will cause very astringent tastes. The scum should be removed from the beer, either by letting it cling undisturbed to the sides of an oversize fermentor, or by skimming it off the krausen, or blowing off the krausen itself from a 5 gallon carboy. I have never had any problems by simply letting it cling to the sides of the fermentor.


Cidery flavors can have several causes but are often the result of adding too much cane or corn sugar to a recipe. One component of a cidery flavor is acetaldehyde which has a green-apple character. It is a common fermentation byproduct and different yeasts will produce different levels of it depending on the recipe and temperature. Cidery flavors are encouraged by warmer than normal temperatures and can be decreased by lagering.

If it is caused by aceto bacteria, then there is nothing to be done about it. Keep the fruit flies away from the fermentor next time.


Diacetyl is most often described as a butter or butterscotch flavor. Smell an unpopped bag of butter flavor microwave popcorn for a good example. It is desired to a degree in many ales, but in some styles (mainly lagers) and circumstances it is unwanted and may even take on rancid overtones. Diacetyl can be the result of the normal fermentation process or the result of a bacterial infection. Diacetyl is produced early in the fermentation cycle by the yeast and is gradually reassimilated towards the end of the fermentation. A brew that experiences a long lag time due to weak yeast or insufficient aeration will produce a lot of diacetyl before the main fermentation begins. In this case there is often more diacetyl than the yeast can consume at the end of fermentation and it can dominate the flavor of the beer.

Dimethyl Sulfides (DMS)/ Cooked Vegetable Flavors

Like diacetyl in ales, DMS is common in many light lagers and is considered to be part of the character. DMS is produced in the wort during the boil by the reduction of another compound, S-methyl-methionine (SMM), which is itself produced during malting. When a malt is roasted or toasted, the SMM is reduced beforehand and does not manifest as DMS in the wort, which explains why it is more prevalent in pale lagers. In other styles, DMS is a common off-flavor, and can be caused by poor brewing practices or bacterial infections.

DMS is continuously produced in the wort while it is hot and is usually removed by vaporization during the boil. If the wort is cooled slowly these compounds will not be removed from the wort and will dissolve back in. Thus it is important to not completely cover the brewpot during the boil or allow condensate to drip back into the pot from the lid. The wort should also be cooled quickly after the boil, either by immersing in an ice bath or using a wort chiller.

When caused by bacterial infection, DMS has a more rancid character, more liked cooked cabbage than corn. It is usually the result of poor sanitation. Repitching the yeast from an infected batch of beer will perpetuate the problem.

Estery / Fruity

Ales are supposed to be slightly fruity, and Belgian and German wheat beers are expected to have banana flavor components, but sometimes a beer comes along that could flag down a troop of monkeys. Esters are produced by the yeast and different yeast strains will produce different amounts and types. In general, higher fermentation temperatures produce more esters. Next batch, contrive to lower the fermentation temperature by a few degrees.


Flavors reminiscent of chlorophyll and fresh cut grass occasionally occur and are most often linked to poorly stored ingredients. Poorly stored malt can pick up moisture and develop musty smells. Aldehydes can form in old malt and can contribute green grass flavors. Hops are another source of these green flavors. If the hops are poorly stored or not properly dried prior to storage, the chlorophyll compounds will become evident in the beer.

Husky / Grainy

These flavors are akin to the astringent flavors produced from the grain husks. These flavors are more evident in all-grain beers due to poor grain crushing or sparging practices. If the grain husks are shredded during crushing by the use of a Corona grain mill for instance, these husk flavors are more likely to be extracted during the sparge. Follow the same procedures recommended to prevent astringency to correct the problem.

Grainy flavors can also be contributed by highly toasted malts. If you are making your own toasted malts, allow them to age at least two weeks after crushing so the harsher aromatic compounds can dissipate. Cold conditioning the beer for a month or two will often cause these harsh compounds to settle out with the yeast.


These flavors are often described as mediciney, Band-Aid™ like, or can be spicy like cloves. The cause are various phenols which are initially produced by the yeast. Chlorophenols result from the reaction of chlorine-based sanitizers (bleach) with phenol compounds and have very low taste thresholds. Rinsing with boiled water after sanitizing is the best way to prevent these flavors.


Metallic flavors are usually caused by unprotected metals dissolving into the wort but can also be caused by the hydrolysis of lipids in poorly stored malts. Iron and aluminum can cause metallic flavors leaching into the wort during the boil. The small amount could be considered to be nutritional if it weren’t for the bad taste. Nicks and cracks ceramic coated steel pots are a common cause as are high iron levels in well water. Stainless steel pots will not contribute any metallic flavors. Aluminum pots usually won’t cause metallic flavors unless the brewing water is alkaline with a pH level greater than 9. Shiny new aluminum pots will sometimes turn black when boiling water due to chlorine and carbonates in the water.

The protective (grayish) oxides of aluminum can be enhanced by heating the clean pot in a dry oven at 250°F for about 6 hours.


Molds are quickly recognized by their smell and taste. Black bread molds and mildew can grow in both wort and beer. Contamination is likely if the wort or beer is exposed to musty or damp areas during fermentation. If the infection is caught early enough, it can often be removed by skimming or cleaning of the surface before it significantly contaminates the batch. Chances are though that the spores have contaminated the batch and it could crop up again.


Oxidation is probably the most common problem with beer including commercial beers. If the wort is exposed to oxygen at temperatures above 80°F, the beer will sooner or later develop wet cardboard or sherry-like flavors, depending on which compounds were oxidized. See the discussion of oxygen and the wort in Chapter 6 – Yeast.


Soapy flavors can caused by not washing your glass very well, but they can also be produced by the fermentation conditions. If you leave the beer in the primary fermentor for a relatively long period of time after primary fermentation is over (“long” depends on the style and other fermentation factors), soapy flavors can result from the breakdown of fatty acids in the trub. Soap is, by definition, the salt of a fatty acid; so you are literally tasting soap.


This group of flavors is very similar to the alcohol and ester flavors, but are harsher to the tongue. These flavors often result from a combination of high fermentation temperatures and oxidation. They can also be leached from cheap plastic brewing equipment or if PVC tubing is used as a lautering manifold material. The solvents in some plastics like PVC can be leached by high temperatures.


Skunky or cat-musk aromas in beer are caused by photochemical reactions of the isomerized hop compounds. The wavelengths of light that cause the skunky smell are the blue wavelengths and the ultraviolet. Brown glass bottles effectively screen out these wavelengths, but green bottles do not. Skunkiness will result in beers if the beer is left in direct sunlight or stored under fluorescent lights as in supermarkets. In beers which use pre-isomerized hop extract and very little flavoring hop additions, the beer will be fairly immune to damage from ultraviolet light.


The cause of this flavor is pretty easy to understand. If the yeast is unhealthy and begins autolyzing it will release compounds that can only be described as yeasty. Also if the beer is green, too young, and the yeast has not had time to settle out, it will have a yeasty taste. Watch your pouring method too, keep the yeast layer on the bottom of the bottle.

How do I know when my beer is done fermenting?

The only sure way to know when a beer is done fermenting is by taking hydrometer readings after you see that fermentation has visibly come to a halt. Most beers are done fermenting after a few days. Some can take longer depending on the amount of fermentable sugar, yeast strain and temperature. If your hydrometer readings show that your beer is around the same gravity for a few days in a row than it has stopped.

Even more importantly, you should take a starting gravity so you have an idea of what alcohol by volume your beer finishes with. Knowing your starting gravity should also clue you in on what your finishing gravity should be given you know what sort of attenuation your yeast strain is capable of achieving.

Making a Yeast Starter

What You’ll Need:

  • A clean container to hold your wort. Needs to be big enough to have some headspace.
  • Aluminum Foil
  • Light Dry Malt Extract (DME)
  • Yeast Nutrient
  • Water

When making a yeast starter it is important to start with an original gravity that is going to promote the health of the yeast as well as growth. If your O.G. is to low you won’t get a lot of growth. This would require you to step up your volume via another starter wich means more handling of the yeast which is an increased risk for contamination.

On the other side of the equation, you don’t ever want to make a yeast starter with too high of an O.G. There is never a scenario where this is beneficial. It wears the yeast down. Ideally, you want to make your yeast starters around 1.030 – 1.040 O.G.

If you are just trying to revive some yeast that may have been sitting for a while you can do a low gravity starter, usually around 1.020 and that will re-energize the yeast but won’t promote a lot of growth. The easiest way to get your wort into the correct range for optimal health and growth is to use the 10 to 1 rule. For every 10 mL or wort, add 1 gram of DME. So if you want to make a 1L yeast starter you would use 100g of DME. A 500mL starter would require 50g of DME.

If making a yeast starter is something you want to get in the habit of doing regularly, I suggest buying an Erlenmeyer flask that is made out of Borosilicate glass. Using these flasks, you can add your water, DME and yeast nutrient and put the flask right on the burner of your stove for 15 minutes. DO NOT, I repeat, DO NOT leave your Erlenmeyer flask unattended on the stovetop. You will have a boil over. It is tricky trying to achieve a gentle rolling boil and not having it get out of control. Be on stand-by with some oven mits in case you need to pull your flask off of the heat when the wort starts to creep up towards the top.

Once you have boiled your wort for 15 minutes, take it off the burner and put it in a water bath to cool it down to a pitchable temperature. It is crucial to put a piece of sanitized tin foil over the top of it at this time also to prevent any spoilers from settling on top of your sanitized wort.

Once cooled, add your yeast and cover it back up. If you have a stir plate, sanitize your stir bar and add it to the starter. If you aren’t using a stir plate, you can simply keep your starter someplace that you walk by frequently. Every time you walk passed it, pick it up and give it a swirl. This will help to promote growth by working oxygen into the wort. Oxygen is also important to the yeast because they need it to build up sterols and to synthesize unsaturated fatty acids which help to promote healthy cell membranes and growth.

When your starter is done fermenting, you can put it in the fridge so that all of the yeast will flocculate out. Before you pitch it into your wort you should let it warm up at room temperature. You can pitch the whole starter or decant the beer off of the top of the yeast cake and then pitch. I prefer to pour the beer off and swirl the yeast to get it all mixed together and then pour it into the fermenter. Good luck with this process, it can really help make a better beer.

A great book to read for a homebrewer looking to learn more about yeast is “Yeast: The Practical Guide to Beer Fermentation”. By Jamil Zainasheff and Chris White.