Beer Flavor & Evaluation

Question 1

Discuss the effects that these adjunct grains have on beer: corn, rice, rye, oats, and wheat.

Answer 1

Corn and rice serve to lighten the body of a beer by adding lots of sugar, but little else. They are commonly used in industrial light lagers. Rye provides lots of spicy flavor and proteins that give the beer body and extra head. Oats provide a smooth nutty flavor and proteins that give the beer more viscosity and head. Wheat adds a bready flavor and extra protein for body and head

Question 2

What do brewers usually have to do to adjunct grains to prepare them for the mash?

Answer 2

Many adjunct grains used raw need to be separately gelatinized prior to being added to the mash. Gelatinizing the grains is like making hot cereal. The grain is swelled in hot water, which makes the starch in the grain accessible to enzymes in the mash that break them down into fermentable sugars.

Question 3

Discuss the use of peat smoked malt in Scottish beer.

Answer 3

Peat smoked malt is sometimes used to make Scottish style beers. It adds an earthy phenolic note. Note this is not appropriate as more than a very minor note for those styles. The Scots did not traditionally use peat smoked malt to make those beers, any peat character came from the yeast or from the water passing through peaty soil.

Question 4

Discuss the effect of using simple sugar to make beer?

Answer 4

Sugars lighten the body of beer because they are nearly 100% fermentable and do not add unfermentable proteins or starches to the beer. White sugars don’t add flavor, but many of the other darker sugars (maple syrup, agave syrup, molasses, treacle) will provide their own unique flavorings to the beer.

Question 5

Name some bacterium used in beer making. What flavors do they provide?

Answer 5

Acetobacter, Pediococcus, Enterobacter, and Lactobacillus. Lacto and Pedio typically provide a lactic tartness to the beer as well as some fruity aromas and flavors. Enterobacter is bilious (vomit-like). Acetobacter oxidizes alcohol into acetic acid, i.e. vinegar.

Question 6

Discuss the flavors that wood ageing commonly provides a beer.

Answer 6

Wood contributes woody or oaky flavor (oak is common for barrels), vanilla (from vanillins in wood), caramel, butterscotch, toasted bread or almonds (if the barrel was toasted), coffee, chocolate, cocoa (from charred wood), and flavors from any wine or liquor that was stored in it. Barrels are also used to age beer with souring organisms.

Question 7

Discuss the flavors that Brettanomyces commonly provides a beer.

Answer 7

There are many species of Brett, they can give beer very different qualities. Some of the characteristics associated with Brett include acetic tartness (if it has access to oxygen, i.e. aerobic fermentation rather than anaerobic fermentation), cherry pie flavor and earthy “barnyard” and “horse blanket” aromas. These beers are not always tart or sour.

Question 8

Our olfactory system is made up of two separate sensing systems, what are they and how do they work?

Answer 8

The orthonasal system smells aromas you sniff through your nose, while the retronasal system smells aromas in the back of your mouth, throat, and the space between the mouth and nose. The retronasal system experiences aromas more as taste than as smell.

Question 9

The flavor perception system is called?

Answer 9

The gustatory system.

Question 10

What are the five established flavors?

Answer 10

Sweet, salty, bitter, umami (glutamate), sour.

Question 11

What is mouthfeel and what is its major driver in beer?

Answer 11

Mouthfeel is the physical sensation of the beer. A major driver of mouthfeel is attenuation level, how much sugar did the yeast ferment vs. leave in the beer. Well attenuated beer is experienced as crisp and dry. Less attenuated beers are fuller, sweeter, and richer. The more residual sugar, proteins, and other compounds in the beer, the more full-bodied.

Question 12

Name the major factors involved in a beer’s mouthfeel.

Answer 12

Attenuation level of the beer/body, carbonation, temperature, astringency, creaminess, and alcoholic warming.

Question 13

What’s the best way to smell a beer?

Answer 13

Short quick sniffs are most effective for sensing aroma. Long inhalations dry out your mucus membranes and interfere with aroma sensors. Smelling yourself will reset tired aroma sensors.

Question 14

What are some common flavor and aroma descriptors for very pale beers?

Answer 14

Uncooked flour and bread dough.



Very pale beers are often made solely with very lightly kilned “base malts” such as pilsner malt.

Question 15

What are some common flavor and aroma descriptors for golden beers?

Answer 15

White bread, wheat bread, and cracker-like. 



Pale malt is used as the base malt for many of the world’s pale ales, especially those from England and the US. It is kilned just enough to have the aroma and flavor of baked bread rather than unbaked dough.

Question 16

What are some common flavor and aroma descriptors for light amber beers?

Answer 16

Bread crust, biscuity, and graham cracker-like.



These are made with either a darker base malt such as Vienna or Munich or with one of the paler base malts along with an addition of specialty malt that is more highly colored.

Question 17

What are some common flavor and aroma descriptors for amber beers?

Answer 17

Toast, caramel, and piecrust-like.



Deeply amber beer may be made with purely Munich base malt (the darkest base malt), but in most cases amber beers are made with a light base malt and smaller amounts of dark specialty malt.

Question 18

What are some common flavor and aroma descriptors for brown beers?

Answer 18

Nutty, toffee, chocolaty, and dark or dried fruit. 



Brown beers are made via the addition of dark roasted specialty malts or grains that give them loads of deep color and flavors and aromas of toffee, chocolate (milk or dark), or dried fruit.

Question 19

What are some common flavor and aroma descriptors for black beers?

Answer 19

Roasty, burnt, espresso, and coffee-like.



Black beers are always made with plenty of dark roasted specialty malts or grains.

Question 20

What is the primary compound in hops that adds bitterness to beer? What has to happen to it for it to dissolve into the wort?

Answer 20

The substances in hops that add the majority of bitterness to beer are Alpha Acids. They are not soluble in water under normal conditions, but are isomerized by boiling and become soluble in the sweet wort adding bitterness. Alpha Acid levels in hops range from 2-20% of the weight of the hop.

Question 21

What is the most aromatic element of hops?

Answer 21

Essential oils are the most aromatic components in hops. They are very volatile (that’s why we can smell them). Therefore, the longer you boil the hops the more of the aromatic and volatile essential oils you will drive off.

Question 22

What are Beta Acids?

Answer 22

Beta Acids in hops provide bitterness, but less so than Alpha Acids. Beta Acids do not isomerize in the boiling wort, rather they break down slowly over time during fermentation and storage adding low levels of bitterness to beer.

Question 23

What is Lupulin?

Answer 23

The Alpha Acids, Beta Acids, and other aromatic oils and bitter resins are found in waxy globules of Lupulin inside the hop cone.

Question 24

Besides adding bitterness and aroma/flavor, what do hops provide beer?

Answer 24

Alpha and Beta Acids possess anti-bacterial properties and prevent or retard contamination from common bacterial agents such as Pediococcus and Lactobacillus.

Question 25

What is a **Gruit**?

Answer 25

**Prior to using hops** as a bittering agent in beer, brewers used a **mix of bitter herb**s, **plants**, and **spices** as the **balancing agent**. That mixture was called *gruit*. It’s sale was **controlled by local authorities** as a way to **tax** brewers. Today, **unhopped beers** are called ***Gruits***.

Question 26

Where are most **US hops** grown?

Answer 26

**Yakima Valley**, WA

Question 27

Name six **American hops.**

Answer 27

Common *American hops* include **Cascade**, **Chinook**, and **Columbus**. Newer US varieties include **Amarillo**, **Simcoe**, and **Glacier**.

Question 28

Common descriptors for **British** grown hops include?

Answer 28

*English hops* are typically described as **herbal**, **woody**, and **earthy**.

Question 29

Common descriptors for **American** grown hops include?

Answer 29

*US hop* varieties are known for their **citrusy** (especially **grapefruit**), **piney**, and **resiny** (like cannabis) characteristics.

Question 30

What are the four **Noble Hops** and how are they typically described?

Answer 30

There are four hop varietals from this region that are referred to as “*Noble Hops*” – **Saaz**, **Hallertuer**, **Spalt**, and **Tettnanger**. They are known for their **low bitterness** and high levels of **aroma**. often described as **floral**, **perfumey**, **peppery**, **minty**, and **woody**.

Question 31

What two compounds does **yeast** turn **sugar** into, primarily?

Answer 31

**Ethanol** and **CO2**.

Question 32

Name three **British hops**.

Answer 32

Some famous *English aroma hop* varietals include **East Kent Goldings**, **Fuggles**, and **Northern Brewer**. These are commonly used native British beer styles.

Question 33

What are the **common uses** for **Noble Hops**?

Answer 33

They are the common hops used for **continental lager styles** and for **many Belgian ales**.

Question 34

What is the **scientific name** for **ale yeast** and what are some of its basic characteristics?

Answer 34

*Ale yeast* is **Saccharomyces cerevisiae**, it likes to **ferment at over 55° F**, and is "**top fermenting**." *Ale yeasts* tend to produce lots of **fruity esters** and in some cases also **spicy phenols**.

Question 35

What is the **scientific name** for **saison yeast** and what are some of its basic characteristics?

Answer 35

*Saison yeast* is **Saccharomyces cerevisiae**, **regular ale yeast**, but it likes to **ferment hot** and is a **low ester**, **high phenol** yeast that gives *Saison* its **spicy**, **black pepper phenol** character.

Question 36

Why are beers finished with **Brettanomyces** often **very dry**?

Answer 36

*Brett* will **metabolize longer chain sugars** that regular brewer’s yeast cannot. When *Brett* is added to a beer after primary fermentation is complete, the Brett will **slowly** **ferment** the **remaining sugar**, ultimately making the beer **very dry**. This **aging process** can take **many months** or even **years** and is often done in **wood barrels**.

Question 37

What is the **scientific name** for **lager yeast** and what are some of its basic characteristics?

Answer 37

*Lager yeast* is **Saccharomyces pastorianus**, it prefers **lower fermentation temperatures** of **40-45° F** and is considered "**bottom fermenting**." They create a very “**clean**” beer and allow the malt and hops to play the central role in the beer’s flavor profile.

Question 38

What is the **scientific name** for **weizen yeast** and what are some of its basic characteristics?

Answer 38

**Bavarian Weissbier** uses **special ale yeast** called **Saccharomyces delbrueckii**. These strains produce **clove-like phenols** and the **banana** and **bubble gum esters** that typify the **German wheat ales** styles.

Question 39

Discuss the effects of **diacetyl** on beer.

Answer 39

*Diacetyl* is a **buttery aroma** and **flavor**. At high levels it can lend a **slick mouthfeel** to beer. *Diacetyl* is typically described as similar to **movie theater popcorn butter**, in larger amounts it can be like **butterscotch**.

Question 40

What is **H2S** (**hydrogen sulfide**)?

Answer 40

*Hydrogen sulfide* is the classic **rotten egg sulfur** **smell** and flavor. It is **detectable by humans at very low levels**. A **very low aroma** of hydrogen sulfide is **acceptable for lagers** (especially when first opened) but generally is considered an **off-flavor** if detectable at any level in an **ale**. **Stressed yeast produce sulfur**.

Question 41

Where does **diacetyl** come from and how can it be avoided?

Answer 41

*Diacetyl* **leaks out of yeast cells** **during fermentation**, typically the yeast **reabsorb** it during the "**secondary fermentation**" stage and process it into flavorless compounds. Sometimes the **elimination of diacetyl** will **not** take place if the yeast are **stressed** or if the **temperature drops**, causing the yeast to stop working. **Infectious** **organisms** also produce *diacetyl*.

Question 42

What causes **band aid**, **clove**, and **peppery** flavors in beer?

Answer 42

These are all **phenols**. Some **yeast strains** produce more than others. *Band aid* is never an acceptable one, but **clove** and **spice** are **features of certain beer styles** (but unacceptable in others).

Question 43

Discuss **acetaldehyde**.

Answer 43

*Acetaldehyde* is an **aroma**, not a flavor. It is described as **green apple**, **apple skins**, and **green leaves**. *Acetaldehyde* is **never appropriate** in beer. When acetaldehyde remains in a beer it's a "**green beer**" that is either **too young** or in which the **yeast** was **not allowed to finish cleaning** up the beer.

Question 44

What is **4-Vinyl Guaiacol**?

Answer 44

*4-Vinyl Guaiacol* is a **phenol** that **smells** and **tastes** like **clove**. It is common in **German Weizen** beers and **some Belgian** beers.

Question 45

What **off flavors** are produced by **contaminant organisms**?

Answer 45

**Brettanomyces** or **wild yeast** or **bacteria** such as **Pediococcus**, **Lactobacillus**, or **Acetobacter** can create **diacetyl**, **bad phenols**, **vinegary acetic acid**, and **tart lactic acid** in beer. They can get into the beer at the brewery or in draft systems.

Question 46

What is a common combination of **off flavors** that occur from **poorly cleaned draft lines**?

Answer 46

**Acetic acid** (**vinegar**) and **diacetyl** (**buttery**).

Question 47

Discuss the flavors of **oxidation**.

Answer 47

Common flavors of *oxidation* range from **honey** (**2,3- pentanedione**), to **papery**, **stale**, or like **wet cardboard** (**Trans-2 Nonenal**). In a **pale beer** the **Trans-2 Nonenol** created by *oxidation* can lend the beer a **waxy** or **lipstick like** flavor. In **dark high alcohol beer** low levels of *oxidation* can be experienced as a pleasant **sherry- like** character.

Question 48

What is **Trans-2 Nonenol**?

Answer 48

*Trans-2 Nonenal* is both an **aroma** and a **flavor**. It comes across as **papery**, **stale**, or like **wet cardboard**. It is **never appropriate**, it is the sign of a **stale oxidized** beer.

Question 49

What **accelerates** **oxidation**?

Answer 49

The *oxidation* process is *accelerated* if beer is **stored** at **high temperatures** – **oxidation** and **heat** are **enemies** of **fresh** beer.

Question 50

What is **Mercaptan**?

Answer 50

*Mercaptan* is an **aroma** that smells like a **skunk’s spray**. It happens to beer that is “**light struck**” by **sunlight** or **indoor lighting**. It is common to beer sold in **green bottles**. To some people it smells **rubbery**.

Question 51

What causes a beer to **skunk**?

Answer 51

*Skunkiness* is formed by a **reaction** of **hop isohumulone compounds** with **high-energy light** wavelengths such as **UV light**. Those hop compounds turn into the compound that **skunks spray**. This can happen in just **seconds**. **Sunlight** & **fluorescent** **lights** in coolers can cause skunking,

Question 52

Beer is most likely to **skunk** in which **packaging**?

Answer 52

**Brown bottles** are **good**, but not perfect, protection for the beer. **Clear**, **blue**, and **green** bottles offer **very little protection** from skunking. **Miller** and possibly a few other industrial brewers **modify** their **hop bittering compounds** in labs to keep it from skunking in their clear and green bottles. **Kegs** and **cans** are **great protection**.

Question 53

Discuss **autolysis**.

Answer 53

*Autolysis* is a **soy sauce-like**/**umami** **flavor** and **aroma** created as **dying** **yeast** consumes each other for food. As **cell walls break** they pour **lipids** and **amino acids** into the beer. This typically occurs in **beer** **packaged** with **yeast** that has **aged**. Generally an **off-flavor**, but a small amount of **umami** in **strong aged beers** can be **pleasant**.

Question 54

What is **Isovaleric acid**?

Answer 54

*Isovaleric acid* is an **aroma**. It smells like **stinky cheese** or **feet**. It results from the **improper storage** of **hops** or use of **old hops** to make beer. It is **never appropriate**.

Question 55

What is **hydrogen sulfide**?

Answer 55

**Hydrogen** **sulfide** (**H2S**) is the **aroma** of **sulfuric rotten eggs**. **Sulfur** is a typical **byproduct** of **fermentation**, but it is **volatile** so most is blown off with the carbon dioxide emitted during fermentation. An **occasional whiff of sulfur** when first **opening a lager** is acceptable, but it is always a flaw in an ale.

Question 56

What is **dimethyl sulfide** and what does it **smell** and **taste** like?

Answer 56

*DMS* is a **sulfur compound**. It has the **flavor** and **aroma** of **cooked corn**, **creamed corn**, or **cooked vegetables**. In **dark beers** *DMS* can taste like **tomato juice**.

Question 57

Where does **DMS** come from?

Answer 57

*DMS* is created when a **precursor chemica**l, **SMM** (**S- Methyl Methionine**), which comes from **malt**, is **heated**. **SMM** turns into *DMS* in **hot wort**.

Question 58

How can a brewer **avoid** **DMS**?

Answer 58

*DMS* is **extremely volatile** and boils out of the wort if there is a good **rolling boil** and the brewer leaves the lid off the kettle. The brewer should also **cool the wort rapidly** to ensure very little DMS forms in the beer between the end of the boil and when the wort is cooled.

Question 59

Which **malt** is the most likely to create a beer with **DMS**?

Answer 59

**SMM** comes from *malt*. The **lighter** the kilning/roast, the more SMM remains in it. **Pilsner malt** is the lightest malt and therefore is a common cause of DMS off- flavor. When making beers that are largely **pilsner malt**, brewers can ensure they steam off the majority of DMS by during an **extra long boil**.

Question 60

What does **acetaldehyde** **smell** and **taste** like and what causes it?

Answer 60

The **apple** *acetaldehyde* aroma and flavor of "**green beer**" comes from the brewer not giving the yeast enough **time** to **complete** **fermentation** and **condition** the beer. Yeast always create **acetaldehyde** during **fermentation**, if allowed time to **clean** the beer up at the end of fermentation they **reabsorb** and process the acetaldehyde out of the beer.

Question 61

If there **DMS** character in a beer is **very strong**, what does that **smell** like and what may have **caused** it?

Answer 61

If the *DMS* **sulfur** character is very strong and **cabbage** like, it may be the result of **contamination** rather than the **heating** of **precursor** **chemicals** in **malt**.

Question 62

What are **tannins**?

Answer 62

*Tannins* are **astringent** **polyphenols** contained in the **husks** of **malt**. If the brewer used **improper** **milling** (**over** **milling**) or **mashing** (**too hot**) processes they can **leech** **tannins** from the **grain husk** into the beer. **Astringency** can also result from **over hopping** or from **spoilage organisms**.

Question 63

What is **astringency**?

Answer 63

*Astringency* is a **drying** **mouthfeel** **sensation** on the **palate**, like you experience from **overly steeped tea** or **tannic red wine**. **Astringency** is a **mouthfeel**, not a flavor or aroma.