Brewl Sensory Analysis

7/30/2019 Brewl Sensory Analysis

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Sensory Analysis

Lyn Kruger

Siebel Institute of Technology

The Importance of Aromasand Flavors on Beer


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Sensory Analysis: The Importance of Aromas and Flavors on BeerLyn Kruger, Siebel Institute of Technology

The sensory analyst is considered an instrument

Senses are used to:

perceive and react

to characteristics of

food and beverages

Sensory Analysis


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The sensory analyst is considered an instrument:

Measure

Analyze

Interpret

Sensory Analysis


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Humans as instruments

cognitive and cultural bias

individual acuity differences

Sensory Analysis


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Sensory analysts may vary from one test to the next:

Fatigue

Adaptation

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Ability to discriminate between harmful and benign stimuli

Health and age play a role

Ability to improve with practice

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Can taste many flavor compounds

Basic tastes

sweet, salty, sour, bitter, umami

Acute sense of smell

Trigeminal sensations:

burning, cooling, tingling

> 1,000 odors and flavors in beer

Sensory Evaluation: What we know


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Olfactory System


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Trigeminal Sensation


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Establish memory for aromas and flavors

recognize and identify aromas and flavors

choose correct descriptors

Sensory Evaluation: Training objectives


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Flavor Wheel


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Aroma impressions first, drive by then 2-3 short sniffs

Small sips

Allow sample to sit on tongue for a moment, then swallow

Basic Tastes: Sensory procedure


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Avoid oversaturation and sensory fatigue

Allow 15 - 60 seconds between samples to readapt receptors

Less flavored samples before highly flavored samples

Basic Tastes: Sensory procedure


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Beer sample quickly moderates towards 37C in the mouth

Immediate (in some individuals copious) secretion of saliva inresponse to oral stimulation

This is promoted in beer by its acidity, alcohol content and highlevel of carbonation.

Saliva is a well-buffered, high pH (7.0) diluent, and influencesthe sensory perception of beer

Basic Tastes: What happens


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Sensory Analysis

Lyn Kruger


BREWHOUSE ASSOCIATED

FLAVORS


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Positive Flavors

Malty

Hoppy

Bitter

Off flavors Dimethyl sulfide (DMS)

Isovaleric acid

Flavors Associated with Brewhouse


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Standard Malts

Cereal

Grain

Sweet

Nutty

Malty

Caramel/Color Malts

Caramel

Toffee Nutty

Slightly burnt

Roasted Malts

Burnt

Bitter

Coffee

Malty: Typical Flavors


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Hoppy

Use Aroma hop varieties

Aroma Associated with Hop Oils :

Floral Compounds

Citrus Compounds

Noble aroma-herbal, spicy - oxidation products

Bitter

Use Bittering hop varieties

Bitter flavor associated with resins

Hoppy & Bitter


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Flavor

creamed corn, vegetable, oysters, tomato juice

Formation

Precursor (S-methyl methionine [SMM])

formed in the barley Some SMM remains in the malt

During wort boiling SMM is converted to DMSand lost by volatilization

Dimethyl Sulfide (DMS)


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Flavor

cheesy, sweat socks

Production

Formed in old hops

Organic acid

Isovaleric Acid


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Sensory Analysis

Lyn Kruger


FERMENTATION RELATED

FLAVORS


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Flavors

fruity, banana, apples, perfumy, solvent,nail varnish remover

Production

Reaction of alcohol group and acid groupin the yeast cell

Iso amyl acetate (Fruity)

Ethyl Acetate (Solvent)

Esters


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Flavor

buttery, butterscotch

Production

During yeast growth in fermentation

When the yeast has to make a specific amino acid - valine

Diacetyl


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Flavor

sulfury, rotten eggs, burnt rubber, strikinga match

Production

Intermediates in amino acid metabolism When yeast needs to make sulfur

containing amino acids

Sulfur Compounds


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Sensory Analysis

Lyn Kruger


STORAGE ASSOCIATED

FLAVORS


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Any flavor changes after maturation - generally negative(off-flavors)

Few exceptions (e.g. barley wines)

Flavors normally associated with staling of the beer

Papery

Bready/Cooked

Skunky

Aldehydic

Flavors associated with Product Storage


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Flavor

papery, wet cardboard, stale.

Formation

Oxidation of linoleic acid

Forms trans-2-nonenal (an aldehyde) Very low flavor threshold (1 ppb)

Oxygen /light promotes reaction

Papery

B d / C k d


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Flavor

cooked breakfast cereal, oxidized, cooked

Formation

Overpasteurization( particularly in the presence of air)

Oxidation reactions

Bready / Cooked

Ald h di


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Flavor

Nutty, toffee, honey, green apples, aldehydic

Formation

Degradation of amino acids

Oxidation of higher alcohols Oxidation of isohumulones

Oxidation of lipids

Oxidation of ethanol (acetaldehyde)

Aldehydic


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Sensory Analysis

Lyn Kruger


CONTAMINATION RELATED

FLAVORS

Fl i t d ith C t i ti


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These flavors are generally off-flavors

Can be microbial or non-microbial

Microbial

Variety - depending on microorganism

Cloves (eugenol, 4-vinylguaicol) Acidic (lactic, acetic acid)

Diacetyl

DMS

Sulfur

Flavors associated with Contamination

Microbial: Cloves / Spicy


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Flavor

phenolic, cloves, spicy

Formation

Associated primarily with wild yeast

In some beer styles - deliberate

Microbial: Cloves / Spicy

Acidic


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Flavor

sour, vinegar, sour milk, acetic, lactic acid, acidic

Formation

Beer spoilage bacteria

Lactic acid bacteria -Lactobacillus

&Pediococcus

Produce lactic acid and acetic acid (only Lactobacillus)

Acidic

Diacetyl


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Flavor

buttery, butterscotch

Formation


Lactobacillus &Pediococcus Wort spoiling bacteria

Enterobacteriacea

Diacetyl

DMS


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Flavor

cooked vegetable, corn, olives, oysters

Formation

Wort spoiling bacteria

Often grow in plate heat exchangers

DMS

Sulfury


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Sensory Analysis: The Importance of Aromas and Flavors on Beer

Flavor

sulfur, rotten eggs, mercaptan

Formation

Wort spoiling bacteria


Sulfury

Brewl Sensory Analysis

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