1. Troubleshooting & Quality Analysis
Brewing Science
Troubleshooting & Quality Analysis

2. Why Evaluate Beer Quality control and Consistency
To be able to describe beer
To score and/or judge a competition
To define styles
To detect problems and improve your own or someone else’s beer
Provided by Terafan Greydragon

3. Flavor Profile Appearance (Visual examination)
Aroma/Bouquet (Olfactory examination)
Taste (In the mouth examination)
Overall impression (General quality)

4. Use all six senses Sight Hearing Smell Taste Touch and feel “Pleasure”
Many of these go hand-in-hand with the flavor profile, i.e.
Appearance with sight
Aroma/Bouquet with Smell
Taste with Taste
Overall impression with Pleasure

5. Sight Head space in the bottle Surface deposit inside the bottle neck
Gushing
Haze
‘Legs’
Foam stability/Head retention
Clarity
Excessive headspace is an indication that air content may be high. Oxidized flavor and aroma may follow.
Surface deposits indicate bacterial or wild yeast contamination
Haze may be an indication of bacterial contamination or just protein-tannin compound
Legs (when pouring a barley or doppelbock) will be indicated on the sides of the glass
Lack of foam stability indicates old, stale, and oxidized beer. Head retention is largely a matter of preference. Generally speaking, NO HEAD or EXCESSIVE HEAD (to interfere with drinking) are equally undesirable.
Brews with all barley malt and lots of hops (esp fresh) ten to have creamier heads.
Some beers are not meant to be clear. If a bottle conditioned beer is being considered for clarity, it must be poured carefully to not disturb the sediment.

6. Hearing
Level of carbonation
Specific tones for specific levels of CO2

7. Smell - (Aroma/Bouquet)
Volatiles/Aromatics
Diacetyls
Phenolic character
Esters
Aroma from malt, grain, and fermentation
Bouquet directly attributable to hops
Odor - (Sulfur based compounds/oxidation)
The most sensitive and telling sense is the sense of smell. However, our smell detectors quickly become anesthitized to whatever we are smelling.
The aroma should be quickly assessed. Swirl the beer in the glass so volatiles and aromatics will change from liquid to gas, carried by molecules of carbon dioxide.
Some aspects are so volatile that they disappear very quickly, esp sulfur based compounds, like DMS.
The aroma of beer can be defined as the smell of beer relative to the malt, grain, and fermentation byproducts. The most common aromas are those of malty sweetness, caramel, toffee, roasted, toasted, or chocolate. Malt contributes indirectly to may other aromas that are the result of fermentation.
The bouquet of beer can be defined as the aromatics that hops contribute to beer. The bouquet of beer will vary to a great degree. When present it can be described as flowery, spicy, pungent, etc.
Odors may be attributed to defects in the beer. Defective beer can be the result of mishandling (extreme temperature changes or agitiation), bacterial contamination, oxidation or being ‘light struck’.

8. Taste Bitterness - Hops, Tannins, Malt, Minerals
How beer affects the sensation of taste
Bitterness - Hops, Tannins, Malt, Minerals
Sweetness- Malt, Hops, Esters, Diacetyl
Sourness- Carbonation, Contamination
Saltiness - Minerals
Bitterness - The degree of bitterness can be influenced by:
Hops - The most assertive influence on bitterness in beer. A dry bitterness
Tannins - Tannins from husks and grains can contribute an astringency taste
Malt - Roasted malts can contribute to bitterness
Minerals - Mineral salts can influence the extraction of bitterness from hops and malt, influencing flavor.
Sweetness - The degree of sweetness can be influenced by:
Malt - Malt has the most influence on the percetion of sweetness. It can contribute unfermented sugars and unfermentable dextrins. The dextrins give beer a fuller body that can help perception of sweetness.
Hops - The flowery and floral nature of hops can sometimes be interpreted as a sweetness.
Esters - Esters are by-products of fermentation, are fruity in nature and can lend to the perception of sweetness.
Diacetyl - Diacetyl, a by-product of fermentation, is butter-scotch flavored in nature and can lend to the perception of sweetness.
Sourness - The degree of sourness is proportional to the acidity of the beer and can be influenced by
Carbonation - Carbon dioxide when dissolved in beer takes the form of carbonic acid. An excessive amount of carbonation will contribute an acidic flavor to the beer
Contamination - Bacterial and wild yeasts can produce acids such ans acetic acid (vinegar) and lactic acid.
Saltiness - The degree of saltiness is influenced by
Minerals - An excessive amount of certain minerals can contribute to a salt flavor in beer. Calcium, magnesium and sodium are usually the culprits.

9. Touch and Feel Texture - creamy, over/under carbonated
Body - full bodied or thin...
Astringency - Dry, puckery feeling (Not really a flavor)
Others - Oily, menthol-like, burning, etc
The tactile feel of bubbles in the mouth perceptibly determines the degree of carbonation. The feel of bubbles can also vary with the ingredient used.
A big and explosive bubble feeling in the mouth is due to the use of fermentable ingredients other than barley malt. A beer made with all barley malt will tend to have a smaller bubble feeling (almost a creamy sensation) in your mouth.
Literally how a beer feels in your mouth, FULL or LIGHT. The unfermented sugars and dextrins contribute to the degree of fullness.
DEXTRINS -Unfermentable carbohydrates that add to body. Technically 4 or more glucose molecules linked together.

10. Pleasure Overall impression Close your eyes- Is it memorable?
Would you want another one?
This is the most personal and subjective category, but probably the most important to consider
Your own genetic make up can have a distinct impact on this, as well as the time of day, time of year, activity level After biking several miles, who wants a heavy rich stout, or on a cold evening are you really in the mood for a light pils?
Even if you don’t like a stout or pilsener, you can still appreciate it for what it is meant to be for others.

11. Maximizing Flavor Perception
Begin with lighter styles and progress to darker, more full bodied beer
Don’t smoke or be in a smoky room
Do not eat salty or greasy food while tasting
Do not wear lipstick or Chapstick
Eat french bread or saltless crackers to cleanse palate
Use clean glassware
As your taste buds become used, it is harder and harder to identify light weak flavors
Smoking deadens your taste buds
Greasy lips will devastate head retention
The waxes in lipstick and Chapstick will destroy head retention
Soap and oils left on glass will destroy head retention and ‘legs’

12. Evaluating Beer Appearance Odor Examine bottle for sediment
Pour the beer
Quickly sniff the beer
Examine the beer in the glass
Odor
Aroma (non-hop odors from raw materials)
Bouquet (odor from fermented elements)
Hop nose (hop aroma of beer)
Appearance - Certain beers should have sediment, others should not. Export class should NOT have ANY sediment.
- Pour about 4-6 oz of beer to create a 3/4 in. thick head. Do not fill the glass more than 2/3 full.
- Volatile aromatics (e.g. dry hopping nose) do not linger and must be caught right after pouring. Take 2-3 quick whiffs, swirl the beer, and take several more short sniffs.
- For a period of approximately one minute, examine the beer for color, clarity, gas release and head condition and stability.
- Gas bubbles should be small, compact, and continue to be released. If the room is quiet, you can listen for the sound of foam disintegration, which should be a series of clicks, not a steady buzz
- Head condition and stability. After a one minute period, the head should have collapsed less than 50%.
Aroma - Low hopped American beers and dark lagers and brown ales will have the greater aromatic intensities.
Bouquet -
Hop nose - Should have a distinct or neutral hop character, and you should be able to detect it.
Negative odors should not be present.

13. Evaluating Beer - cont’d
Taste in the mouth
Take a good sip
Swirl and slosh around your whole mouth
“Swizzle” (suck in air through beer in your mouth)
Small sip to check 4 tastes
Check Astringency
Check after-taste or tail
General Quality
Memorableness or “come hither appeal”
A good sip is about 1 tablespoon, 15 ml. “Swizzle’ by opening your mouth and inhaling some air. This aerates the beer and excites the olfactory at the base of the nose.
Use the small picture of the tongue to record the basic tastes IN ORDER on your tongue. Sweet, salt, sour, and bitter.
Pass a small sip along the inside of your lower lip (to check astringency).
One more sip to evaluate the aftertaste or tail.
General quality - Does the beer make you want to have another?
Close your eyes. How does it make you feel?

14. The ‘taste’ of beer Hop quality Hop intensity Sweet/dry balance
Beer character
Aftertaste or tail
Body and Palatefullness
Flavor balance
Hop Quality - There should be a good varietal taste, smell, and aftertaste. Pronounced, moderate, lacking as appropriate
Hop Intensity - should be correct for the type of beer
Sweet/dry balance - Balance should be appropriate.
Beer character -Sum of the non-hop, non-sweet/dry characteristics of beer. Malt and grain character, fruit flavors, special nuances, and spices. Excessive bitterness, astringency, harsh flavors?
Aftertaste or tail - Some hop character may linger along with other flavors. Should be pleasant and disappear fairly soon. Lingering bitterness, off-tastes, etc ?
Body and palatefullness - alcohol character and richness of the beer. Vinous, neutral, sweet, bland, rough, smooth, etc
Flavor balance - How is the beer “supposed” to taste compared to how it DOES taste?

15. Summary Becoming a knowledgeable beer drinker takes practice
Taste, smell, feel, and look at your product during every step
Evaluate the beer as it ages
What sulfur characters come and go?
Which phenolic characters get worse with age?
How does bitterness and diacetyl rise and fall?

16. Troubleshooting

17. Introduction
Many problems with our brews can be attributed to poor ingredients, poor brewing techniques, or poor sanitation. Fortunately, many of these issues can be identified and resolved.
Provided by Ken Woodson & the North Texas Home Brewers Association

18. Fault Examples Off flavors: fruity, harsh, sweet, or bitter
Haze: level of particles in suspension
Lack of body – level of non-fermentable sugars and polyphenols
Poor head retention or formation

19. Gram Negative/ Gram Positive Bacteria Contamination
Acetic Acid Bacteria
Pectinatus cervisiiphilus
Enterobacteriaceae
Zymomonas
Pectinatus frisingensis
Selenomonas Lacticifex
Zymophilus raffinosivorans
Zymophilus paucivorans
Megaspaera
Gram Positive 
Lactobacillus
Lactic Acid bacteria
Pediococcus
Leuconostoc
Homofermentative cocci
Kocuria, Micrococcus and Staphylococcus
Endospore-forming bacteria

20. Alcoholic
By alcoholic, we mean the aroma, flavor, and warming effect of ethanol and higher alcohols. It can be described as hot.
High levels of fusel alcohols can lead to an alcoholic characteristic in beer. Fusel alcohols have a more complex molecular structure than ethyl alcohol.
Typically, fusel alcohols:
provide an initial sweetness followed by a harsh after taste.
are formed by the metabolism of amino acids, so over modification during malting or mashing can lead to higher fusel alcohol levels.
increase with fermentation temperature, level of amino acids, and wort gravity.
Wild yeast can produce very high levels of fusel alcohols, so use proper sanitation techniques during brewing.
Provided by Ken Woodson & the North Texas Home Brewers Association

21. Astringency By astringent we mean a mouth puckering sensation
Common causes of astringency in beer include:
Extraction of tannins from grain due to over crushing or over sparging.
If the pH of the sparge water exceeds 6 or if the sparge water temperature exceeds 168 °F, then tannins may leak into your wort causing astringency.
Acetic acid bacteria, like acetobacter, can cause sour or vinegary flavors and aromas. Use good sanitation to avoid bacterial contamination.
Provided by Ken Woodson & the North Texas Home Brewers Association

22. Beer Haze
Chill Haze
Haze occurs when the beer is chilled but disappears as the beer warms.
Chill haze is from high molecular weight proteins and polyphenols forming weak bonds. The bonds are broken as the temperature of the beer increases.
To avoid use properly malted grains and use a protein rest.
Also, fining agents can be used to control chill haze. Polyvinylpolypyrrolidone (PVPP) removes polyphenols and silica gels and Irish moss remove proteins.
Provided by Ken Woodson & the North Texas Home Brewers Association

23. Beer Haze
Starch Haze
A permanent haze in beer from large molecular weight carbohydrates, including β-glucans.
Caused by poor mashing and sparging.
To avoid starch haze in beer:
Allow proper starch conversion during mashing
Reduce sparge temperature
Use quality malts that do not have high amount of β-glucans .
Provided by Ken Woodson & the North Texas Home Brewers Association

24. Beer Haze Biological Haze
Bacteria and wild yeast can cause haze in your beer.
To avoid biological haze:
always use proper sanitation during brewing
Pitch proper amount of healthy yeast cells
Use well flocculating yeast strain.
Provided by Ken Woodson & the North Texas Home Brewers Association

25. Beer Haze Oxidation Haze
Over time oxidized compounds in beer can cause protein and polyphenol haze.
This haze will eventually occur in all beers
To control oxidation haze, avoid introducing oxygen into wort and beer, except to aerate yeast at pitching.
Provided by Ken Woodson & the North Texas Home Brewers Association

26. Body
Body means fullness of flavor and mouthfeel. Examples range from watery for Lite American Lager to thick and chewy for a Strong Scotch Ale.
The body of a beer is determined by the amount of dextrins and medium level proteins.
Provided by Ken Woodson & the North Texas Home Brewers Association

27. Body Light beer body is caused by:
Lack of dextrins from low starch conversion temperatures during mashing.
Excessive use of adjuncts.
Using high attenuating yeast strains.
Lack of medium level proteins from long protein rest.
Adding large amounts of fermentable sugars
Using too many fining agents.
Provided by Ken Woodson & the North Texas Home Brewers Association

28. Dimethyl-Sulfide (DMS)
DMS may create an aroma and flavor of cooked vegetables like corn, celery, or cabbage. Low levels are common in Pils malt.
The precursor to DMS is S-methyl methionine (SMM) which is formed during malting. SMM levels are controlled by the maltster.
The brewer can also control SMM by performing a vigorous open rolling boil for at least one hour. The strong open boil will evaporate the SMM.
Provided by Ken Woodson & the North Texas Home Brewers Association

29. Dimethyl-Sulfide (DMS)
After boiling, cool the wort as quick as possible because cooling the wort too slowly can lead to higher levels of DMS.
A vigorous fermentation can reduce DMS levels because CO2 bubbles can carry away DMS.
Wild yeast can also produce high levels of DMS, so make sure you use proper sanitation to avoid these unwanted bacteria.
Provided by Ken Woodson & the North Texas Home Brewers Association

30. Head Retention
For good heat retention, beer needs an adequate supply of polypeptides, with molecular weight between 500 to 12,000. Under modified malts require a protein rest to reduce the higher molecular weight proteins to lower molecular weight proteins.
Another requirement for good head retention is proper carbonation levels.
Fatty acids from wort trub and unclean glassware can reduce head retention by decreasing the surface tension of the beer foam.
Provided by Ken Woodson & the North Texas Home Brewers Association