Have you ever gone to your favorite bar, and ordered your favorite beer? You are so excited for that first sip when those flavors your love dance across your tongue. You put the beer to your mouth, tip it back, and let it slide over your lips. The cold liquid doesn’t even get to your taste buds before you realize, something is wrong. It just doesn’t taste right. There is a flavor in there that isn’t supposed to be, but you just can’t quite put your finger on it. Off-flavors happen sometimes in beer. There are so many different steps and ingredients in producing beer that occasionally something will go arwy, and will effect the out come of the beer.
Luckily, there are ways to learn how to identify these flavors in beer, without having to ruin a ton of home brew batches. But, if you ruin them anyway, knowing how to identify the flavor is a good way to find out what went wrong. One way to learn flavor attributes of beer is with the Seibel Institute Sensory Training Kit comes with 24 viles of pre-measured liquid meant to spike beer with a certain flavor. The kit runs $190, but you can often get a discount on the kit if you are a brewery or through your home brew club. When my homebrew club, Liquid Poets Society, offered a chance for us to participate in this program I jumped on it.
For 3 session, 15 of us will be meeting at the south location of Hops and Berries to taste some pretty awful tasting beer. I am actually really excited! The class is being taught by Joe, our fearless leader and president. He is very knowledgeable on many things beer. I learned so much in just one session. I even had to pull out some of my old biology knowledge when he was explaining exactly how those flavors show up. Think cell membrane permeation. Who knew I would need that phrase again.
Each class will be set up with 8 beers spiked with the liquids from Seibel. We used Coors Light, because of its neutrality, to spike. When we arrived for the first class we sat down with an unspiked Coors Light, to help set a standard and to help calibrate our pallet between flavors. A way to calibrate your sense of smell is to smell your arm or the back of your hand. Your scent will help bring your sensors back to neutral.
This first round we did many esthers and phenols. These compounds are an expression of the process of creating beer. We also did one taint this session, which is a flavor that is added by something other than the process of creating the beer. In addition to tasting the flavor, we also learned how the flavor is created and how to avoid it in brewing.
Here are my notes. I am sure there are some properties or causes that I missed and I would love any input from you if you know something I missed!
- Isoamyl Acetate: an esther that produces banana, bubble gum and cotton candy aromas. It is a fermentation by-product that is caused by the health of the yeast. It is caused by under pitching or stressing out your yeast, meaning not putting in enough yeast to turn the sugars into alcohol. It can often be found in wheat and Belgian beers. The minimum threshold (or the amount needed for humans to taste each flavor) is 1.6 milligram/liter, we tasted it at 4.5 milligram/liter
- Ethyl Hexanoate: An esther that produces red apple like aromas, sometimes also anis or black licorice. This is a fermentation by product caused by yeast health. This is caused by over pitching the yeast, and having not enough sugar for it to turn into alcohol. Common in British ales and can be found open in Scotch Ale yeasts. The minimum threshold is 225 microgram/liter, we tasted it at .6 milligram/liter
- Ethyl Acetate: Another esther that produce solvent like smells and flavors. Often like nail polish remover, acetone. This is caused by wort composition and yeast growth. Under pitching the yeast, acidic acid infections and exposure to oxygen can cause this defect. The minimum threshold is 33 milligram/liter, we tasted it at 90 milligram/liter
- Spicey: A phenol produces clove like flavors and smells. It is caused by the selection of yeast (such as wild yeasts), microbial contamination, pitching rate and temperature of fermentation. It is open found in wheat and Belgian beers, especially ones with wild yeast. The minimum threshold is 30-40 microgram/liter, we tasted it at 120 microgram/liter
- Hefeweizen: This flavor was a combination of the “spicey” and “isoamyl acetate” listed above a phenol and esther respectively. I thought it was interesting that in the mix I got bubble gum for isoamyl acetate, but banana when it was on its own.
- Mercaptain: Not an esther or a phenol, this attribute is often described as sulfur like, smelling of rotten vegetables or sewage. It is a volatile flavor, and will gas off as CO2 is released. It is caused by poor yeast health, and starved or dead yeast. The human threshold for this is 1 microgram/liter, we tasted it at 3.75 microgram/liter.
- Papery: A attribute that needs no real explanation, taste like wet cardboard or paper. It is caused by oxidation of the beer, and being stale. Both of which can be caused by aging a beer for too long.
- Metallic/Tin: The only taint in the group of 24, it tastes like metal, pennies, iron or blood. It is caused by not using the correct metal in your brew equipment, or ions in water. Can also be caused by equipment a beer is being served on. We tasted this one at 3.75 milligrams/liter
While all of the flavor attributes have a minimum threshold, everyone in the group had different flavors they were sensitive too and tasted different things in each flavor. I was wasn’t too sensitive to ethyl acetate, while one person wouldn’t drink more than a tiny of sip of it as it tasted like nail polish remover to him. I didn’t have to taste the papery or metallic spiked beer to be able to identify them. Ever since I had a concussion a few months ago, I have been very sensitive to metallic flavors.
Check back soon, to learn about the other 16 flavors.