Contrary to it’s reputation as a simple, easy alcoholic drink, beer is very complex in regard to smell and taste. There are a lot of things in a beer that give each one it’s unique aroma and taste. This is a 2 part series on the aroma and tastes in a beer. In this post, we will look at the specifics that make a beer taste how it does. This post will get a little science-y, but power through and you will hopefully be able to enjoy your beer even more when you know what it is you are tasting. Combined with the next post on aroma, and you’ll be a pro.
There are five basic flavors that people can taste. Those are:
- Savory (umami)
Sweetness In Beer
As we talked about earlier, beer is created when grain is cooked and sugar is extracted. This sugar is eaten by yeast and alcohol is produced. One would think that this would remove the sugar from the beer, but that would be wrong. There are two main types of sugars in beer, fermentable and not fermentable.
The fermentable ones get eaten by yeast. The sweetness comes from those sugars that yeast cannot digest. Here’s a quick reference, taken from Randy Mosher’s Radical Brewing.
|Compound||Description||Will It Ferment?|
|Glucose||Single Molecule. Found in small quantities in wort||Fermentable|
|Maltose||2 Glucose molecules linked. This is the primary fermentable sugar in beer. Sweet.||Fermentable|
|Maltotriose||3 glucose molecules linked. Barely sweet||Variably Fermentable|
|Maltotetraose||4 glucose molecules linked. Not sweet.||Not Fermentable|
|Dextrins||Between 4 and 25 glucose units. Not Sweet||Not Fermentable|
|Starch||Branching structures of glucose units, around 1,000.||Not Fermentable|
All The Other Flavors
As we stated above, and you probably know, bitterness in beer comes primarily from hops. Other bittering agents have been used, but hops are the primary source. Many other factors play into the taste of a beer, including the water used, the other flavoring ingredients, and the alcohol content. All this adds to the flavor. But, as important as flavor is, aroma plays an equal part in this, as we stated in the post on Tasting Beer.
Let’s Get Specific
With the simpler terms and ideas behind us, let’s take a deeper look at what makes up the taste of beer. It’s these specific tastes that really help you to understand the beer.
- Characteristics: This has the flavor of green apples, as well as the aroma. It can taste cidery or acidic.
- Chemistry: It is formed as a precursor to alcohol by the yeast. Also, as a product of oxidation.
- Causes: This is formed during the process of alcohol production. In this case, it has a crisp flavor, if cause by oxidation, it has a less pleasant acidic flavor. A good yeast strain can fix this issue. Also, oxygenating the wort when pitching (adding) the yeast can help limit this flavor.
- Characteristics: This can be classified as both a smell and a taste. Alcohol gives a specific mouth feel when tasting. This is generally shown in a warm sensation on the tongue and in the back of the throat.
- Chemistry: We have gone over how alcohol is created, but again, it is the result of glucose being turned into alcohol and CO2.
- Causes: Alcohol is caused by yeast consuming fermentable sugars, and is generally the desired result of brewing.
- Characteristics: This is noticed as nerve endings in the mouth are stimulated, and as such, is solely a taste and not an aroma. Think grape skins.
- Causes: The main cause of this is contamination by wild yeast or bacteria.
- Process: Caused by:
- lack of proper cleaning practices
- letting grains boil too long
- over-crushing of grain
- sparging at too high of a temperature
- excessively high acidity in water.
Bitterness in beer, since it is generally a welcome flavor, is measured with IBUs, or International Bitterness Units. Check out this chart for some more information on IBUs.
- Characteristics: As hops are a key ingredient, bitterness is generally a desired characteristic. As we stated above, this is one of the 5 basic flavors.
- Causes: Bittering agents like hops or other herbs. Some grains can also add a level of bitterness as well.
- Characteristics: Butterscotch aroma and flavor. Mouthfeel can be almost slick and oily.
- Causes: Diacetyl is a by-product of yeast during fermentation. This is usually absorbed during secondary fermentation. Weak yeast, or mutated strains can cause this to not be re-absorbed as it should. Lactic acid bacteria in the beer can cause this as well.
- Process: Underpitching yeast is a cause of this, as well as letting wort cool for too long. One of the biggest reasons for this is contamination of brewing equipment, or removing yeast before it is complete.
- Prevention: The easiest way to prevent this is to make sure everything being used is sanitized. Cooling wort quickly can help as well. Using all malt and no adjuncts in brewing will help to stave this off as well.
- Characteristics: Just as the name states, this is characterized by a flavor of fresh cut grass or hay
- Cause: This can be caused by a sub-par malt quality, or the malt being stored incorrectly. The grain being cracked too far in advance of being brewed can be a cause as well.
- Prevention: Storing malt in an air-tight container and not cracking the grain until you are ready to brew are both excellent preventative measures.
DMS and Related Compounds
Cause: The biggest cause of this bad taste is bacteria in the wort. Cooling your wort slowly can also bring this taste forward.
Prevention: The biggest thing you can do to stave off these bad tastes is to properly sanitize. Also, boiling the wort for at least an hour helps to cut down on the bacteria as well. Over-sparging with cooler water, high-moisture malt, and contaminated yeast can all cause this too.
- Characteristics: This is shown with an acetone-like pungent aroma and harsh similar taste.
- Cause: The presence of ethyl acetate in high quantities. Other compounds can give this effect, but this is the major culprit. This can come from wild yeast contamination, poor sanitation, and the use of non-food grade plastic containers.
- Prevention: Some of the ways to prevent this very undesirable taste trait are to first make sure everything is sanitized. This is always the first place to start. If using plastic, use only food-grade, make sure fermentation is at a cooler temperature, and that your fermenter is closed.
- Characteristics: This is one of the basic tastes as we talked about above. Depending on how sour the taste, this will be experience on the tongue and at higher levels, in the throat. Tartness and possibly a vinegar-like taste can be the impression given in beer. Sourness in beer can be a purposeful thing, or a sure sign of contamination and/or spoilage. A future post will talk all about sour beers, a style all their own.
- Cause: The bacteria lactobacillus, acetobacter, and pediococcus can all cause this, as well as some strains of yeast, like Brettanomyces, or Brett.
- Prevention: Proper sanitation, glass carboys, and cool beer storage can all cut down on sour tastes in beer that are not meant to have them.
- Characteristics: Wet paper, cardboard, and rotten fruit tastes and smells can be signs of oxidation. A nutty flavor can also be imparted to the beer.
- Causes: Oxidation of beer can be caused by aeration of the beer when transferring to keg or bottle, too much headspace in bottles, bad airlock, adding tab water to finished beer without boiling.
- Prevention: The best way to prevent this is to disturb the beer as little as possible when transferring. An auto-siphon helps with this. Filling bottles correctly with little headspace, using oxygen-barrier caps, as well as making sure your airlock works are all great ways to prevent this off and unwelcome taste.
Whew! That was a lot of technical stuff. I hope you made it through the list, since knowing these different tastes can help you to know what is wrong with your home brew, and how to fix the next batch. There’s nothing worse than ruining a batch of beer and not knowing how to fix the next one.
It can be said there is no bad batch of beer if you learned at least one thing from it.
There are many other flavors that can show up in beer, but these are the most common. Have a suggestion for more information here or another important taste we didn’t mention? Leave it in the comments below and I’ll keep this updated. Thanks for reading!