Home Brew Beer Kits – Solutions to Common Problems – Part Three: A-Z Off Flavours and What They Mean

First time and even experienced home brewers can be plagued with problems with beer made with home brew beer kits. The beer quality made from these beer kits can be can be outstanding. However, its just as easy to brew beer that is merely average or even undrinkable. Often these middle of the road or terrible beers have off flavours produced from simple mistakes somewhere along the brewing process. Luckily, what off taste has been produced will help you trouble shoot where in the brewing process you went wrong so you can correct it for next time. Read through the list below to identify your taste or smell to help identify what went wrong. In some cases, you can still rescue your beer, If you can’t, at least you won’t make the same mistake next time.

May we present: My beer tastes like… Clues as to what went wrong.

Acetaldehyde – This flavor or aroma reminiscent of green apples or freshly cut pumpkin. In small amounts this can be a good thing in pale lager beers as it can add that “refreshing” taste. In moderate amounts however it can result in apple, emulsion paint, wine or sherry flavours. In large amounts it adds harshness and may make beer undrinkable.

  • Cause: Acetaldehydes are intermediate compounds in the production of alcohol (ethanol). The presence of this flavour then usually means the beer is too young and needed either more time to ferment or to condition. It may also be indicative of bacterial infection. It can be more evident when using either cane or corn sugar.
  • Solution: Ensure good sanitation procedures are followed to avoid infection. Let the beer ferment a week longer, or use a hydrometer to know when fermentation is finished. If your beer is bottled, let it condition another week or two.

Alcohol – A sharp flavour that can taste harsh and detract from the overall beer depth and flavour. It is also sometimes described as having a hot mouth-taste. Some alcoholic taste is desired in strong beers but too much will make is taste like cheap tequila.

  • Cause: Fermentation temperature is too high, or not enough oxygen dissolved in the wort.
  • Solution: Research the temperature that is ideal for your yeast strain and keep your fermenter below the upper limit. Ensure good oxygenation of the wort by aerating thoroughly before pitching (adding) the yeast.

Astringent – You will know this flavour as it makes your mouth pucker! Often described as the same as sucking on a tea bag (who does that?) or eating grape skins. It is not the same as bitterness.

  • Cause: oxidation of the wort, bacterial infection.
  • Solution: Good sanitation, prevent oxidation of the wort (don’t add hot wort to your cold water)

Cidery – Smells like, tastes like apple cider. Nuff said.

  • Cause: adding too much cane or corn sugar. Not letting the beer ferment or condition long enough (acetaldehyde flavour), encouraged by warm temperatures. Contamination.
  • Solution: Good sanitation. Depending on what style of beer you are brewing, eliminate or reduce sugar content. In heavier, darker beers, use more malt extract instead. Keep fermentation temperatures ideal.

Diacetyl – A buttery or butterscotch flavour. Can be desired in pale ales but generally is not appreciated in lagers and can even taste rancid.

  • Cause: Bacterial infection. Poor oxygenation of the wort. Poor yeast growth (weak yeast). Not letting the beer ferment long enough. Fermentation temperatures too high especially in the first stages.
  • Solution: Good sanitation. Good aeration of the wort. Let the beer ferment another week or two or use a hydrometer to know when fermentation is finished. Condition the beer a week or two longer, ensure you don’t condition in the fridge. For ales, keep the fermenter on the cooler side (63 degrees) for the first couple of weeks then bring temperature up to about 68 for the final stages. For lagers, try a diacetyl rest: once fermentation is complete, warm up the beer to the low sixties for 48 hours. Bottle then leave at room temperature for a couple of weeks, then cool condition.

Dimethyl Sulfides (DMS)/ Cooked Cabbage Flavor

  • Cause: infection
  • Solution: Good sanitation

Estery / Fruity – Primarily banana, but other flavours include pear, strawberry, raspberry, grapefruit. Sounds delicious to me, but in large concentrations it will taste very odd.

  • Cause: high fermentation temperatures, poor wort oxygenation.
  • Solution: lower fermentation temperatures, or what is idea for your yeast strain. Proper wort aeration.

Medicinal/Phenols – Described as Band-Aid smells, medicine like or cloves. Chlorophenols can taste like that with a bleach undertone.

  • Cause: Infection, sanitation with chlorine bleach and inadequate rinsing.
  • Solution: Good sanitation and thorough rinsing with boiled water if using a chlorine or bleach based sanitizer.

Metallic – A taste like pennies or blood, primary from iron.

  • Cause: High iron content of water, boiling very alkaline water in an aluminum pot, steel pots (not stainless steel)
  • Solution: use stainless steel equipment, avoid water containing high levels of  iron.

Moldy– Tastes and smells like mold.

  • Cause: contamination during fermentation especially when stored in a damp or musty area.
  • Solution: Store your fermenter in a dry, dark area.

Oxidized/Wet Cardboard/Sherry-like flavours – Tastes like cardboard, paper, pineapple, decaying vegetables, bitterness and harshness.

  • Cause: oxidation of the wort
  • Solution: care when adding the wort to the fermentation water. Do not add hot wort to cold water. Aerate the water first, not after the wort is added.

Skunky – Tastes and smells like it says! Generally not a problem in home brew kits.

  • Cause: reactions between light waves and isomerized hop ingredients. These wavelengths are screened out by brown colours.
  • Solution: Don’t store your fermenter or bottled beer in direct sunlight. Use brown bottles.

Soapy

  • Cause: incomplete rinsing of equipment after cleaning. Leaving the beer in the fermenter too long allows for breakdown of fatty acids which cause a soapy taste.
  • Solution: rinse equipment well after using soap. Don’t leave the beer in the fermenter too long. Long is relative as we have heard of beer sitting in the fermenter for up to 6 months and it being ok. It will eventually happen.

Solvent like – much like the same taste as esters or alcohols but much harsher, like nail polish, paint thinner.

  • Cause: They can occur with the combination of high fermentation temperatures with oxidation. Leached from cheap plastic PVC equipment, especially if exposed to high temperatures.
  • Solution: Control the fermentation temperature and avoid oxidation of the wort. Use only food grade plastics for brewing and ensure that these plastics can still be used at high temperatures (some will leach toxins at high temperatures).

Sour – Tastes like vinegar, acid

  • Cause: Almost always an infection with bacteria or wild yeast. Can be inhabiting scratches in your brew keg or will drift in during brewing or fermentation.
  • Solution: Take care to not scratch your keg and clean thoroughly. Replace your keg if needed. Brew and ferment in a clean, dry area and ensure your keg is well capped. Only open the fermenter when absolutely necessary.

Sulphur – like rotten eggs, a burning match or raw sewage

  • Cause: A natural by-product of fermentation. Infection. Yeast autolysis (death and breakdown).
  • Solution: If a normal by-product, the smell will go away as fermentation proceeds. Good sanitation. Don’t leave the brew in the fermenter for a long time. Again, “long” is relative as we have heard of beer sitting in the fermenter for up to 6 months and it being ok. It will eventually happen.

Sweet – overly sugary, cloying, sweet. Final gravity will be high and alcohol content will be low.

  • Cause: the yeast hasn’t fermented all its sugar – stuck yeast (wont ferment), temperature too low for fermentation. Or it may be unbalanced sweetness; not enough bitterness to counter the sweet so sugary flavours predominate. This may happen with the addition of too much fruit flavour.
  • Solution: Research and keep fermenter at proper temperature for your style of yeast. Add less fruit (you can always add more next batch if your first batch is too subtle). Pitch more yeast.

Thin – poor body, no complexity, boring beer.

  • Cause: The beer has been allowed to ferment too long, the alcohol content is high and final gravity is low. Beer hasn’t carbonated long enough or is over-carbonated.
  • Solution: Do not allow beer to ferment too long, use a hydrometer to determine when to bottle it. Wait another week or 2 for carbonation to occur during conditioning.

Yeasty – tastes or smells like yeast, bread.

  • Cause: Produced from the death and breakdown of yeast (leaving the beer in the fermented too long), or the presence of yeast (beer is too young and yeast hasn’t had a chance to settle out).
  • Solution: Don’t leave beer in the fermenter too long. Allow young beer to condition another week or two.

By now, you are probably bored with how much we talk about sanitation, but it cannot be over emphasized. Almost any of the flavours above can be caused by contamination of the wort by bacteria or a wild yeast strain. If you have off flavours that cannot be explained by any of the troubleshooting tips above, then it’s likely an infection. Have a think about your process and ensure absolutely everything that comes into contact with the beer is sanitized. Don’t give up, and soon you too will create something amazing!

If you don’t understand a term or process talked about here, we suggest you read Part One : Understanding the Process for a refresher.

 

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