Transcript The Science of Brewing - STEM Carib Conference

THE CAYMAN ISLANDS BREWERY
The Science of Brewing
Cecilia Cruz Palma
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Content overview
• Company Introduction
• Brewing step by step
– Raw Materials
• Malt
• Hops
– Wort Production
• Mashing
• Lautering
• Boiling
– Fermentation
• Yeast
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
CIB
• The Cayman Islands Brewery was launched in
2007
• The brewery was designed and modernized
with help of Brewtech specialists, a German
brewing consultant company
• The brewery now produces 4 lager beers and
one bock beer
• Go to: www.cib.ky
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Raw Materials
• Three major raw materials:
Water
Malt
Hops
Beer
According to the German purity law of 1516
• In many countries also syrups, sugar, rice used
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Malt
• Germinated grains
• For beer production mostly barley malt is used
Hordeum vulgare
Source: www.freefoto.com
Source: www.crc.dk
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Malting overview
Source: Rath
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Malting overview
Source: Rath
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Germination
1. Water uptake during steeping
2. Hormones called gyberilic acid released
3. Enzyme production activated
Aleurone layer
Embryo
Endosperm
Source: Methner
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Enzymes
• Enzymes are active proteins which catalyze reactions
Source:
www.biologyguide.net
• Enzymes are substrate specific and their activity
depends mainly on:
– Temperature
– pH
– Substrate concentration
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Barley enzymes
• Germination enzymes in barley make possible
the degradation of higher molecules
• There are three major modification processes
during malting and brewing
Modification
Cytolysis
Cell wall
Amylolysis
Starch
Proteolysis
Proteins
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Cytolysis and Proteolysis
• Breakdown of starch
granule’s cell wall and
protein matrix
• Most important
processes of malting as
path needs to be clear
for further breakdown
enzymes
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Cell wall structure
• Cell wall is built by different components
Protein middle lamella
Source: Bamforth
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Proteins
• Proteins are chains of amino acids folded together
into stable 3D structures
• Proteinases breakdown proteins into short peptides
• These peptides are further
degraded by peptidases
into free amino acids
• Amino acids are “Free
amino nitrogen” (FAN) a
very important nutrient
for the yeast during the
fermentation
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Cell wall structure
• Cell wall is built by different components
Hemicelluloses
Source: Bamforth
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Short reminder
• Sugars act as building unit for many polymers
• Two different structures, here in example of
glucose:
α-Glucose
β-Glucose
• Leads to two different glycosidic bonds
α-glycosidic bond
β-glycosidic bond
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Hemicelluloses
• Are the major component of the cell wall and
give to it its stable hard structure
• Hemicelluloses in barley are:
– β-glucans
– Pentosanes
• Breakdown of hemicelluloses is done by many
different enzymes formed through
germination
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
β-Glucans
• Unbranched chain of cellobiose and laminaribiose
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Pentosanes
• Branched chain of xylan with arabinose
• Ferulic acid can bind to arabinose and creates a more
stable structure
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Amylolysis
• Starch is built by most plants as an energy
reservoir
• Amylolysis is low during germination and takes
place mainly during mashing
• There are two main
enzymes doing this
process
– α-Amylase
– β-Amylase
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Starch
• Starch consists of two chains of glucose units
– Amylose
• Unbranched
• α(14) Glucose
– Amylopectin
• Branched
• α(14) Glucose
• α(16) Glucose
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Amylolysis
• Both enzymes cleave α(14) glycosidic bonds
• α-Amylase is an endoenzyme, works within the
starch chain forming short oligosaccharides
• β-Amylase is an exoenzyme, works only from the
ends and forms
α-amylase
Maltose, Glucose
& other simple β-amylase
sugars
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Malting overview
Source: Rath
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Kilning
• The process of drying the malt with hot air
• High moisture content leads to fast spoilage of the
grains
• The heat causes:
– Water evaporation
– Formation of color and
aroma compounds
– Temporary inactivation
of enzymes
Source:
www.weyermann.de
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Malting overview
Source: Rath
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Malt quality control
• Several parameters have to be controlled at the
brewery before accepting the malt
– Hand bonitierung
• Insects, moulds
• Color, smell
– Water content
– Cell wall modification
• Friabilimeter
• Calcofluor staining
– Protein content
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Hops
• Plant giving beer its bitter profile
Source: Barth
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Hops components
Lupulin
β-acids
Humulin
α-acids
Resins
Humulus
Lupulus
Hops oils
Polyphenols
Xanthohumol
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Hops products
• Nowadays cones are processed into different
products
Hops cones
Hops extracts
Hops pellets
• Worldwide mostly pellets are used
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Brewing overview
Source: Rath
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Mashing
• Milled malt is combined with warm water so that
malt enzymes are reactivated
• Temperature of the
mash must be set
according to the
optimal working
temperature of the
enzymes
Amylolysis
Proteolysis
and cytolisis
Source: Kunze
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Mashing
• Nowadays malts are so well modified that starch
degradation is the main aim of mashing
• Phases of starch degradation:
– Water uptake of starch granules
– Swelling of granules until bursting
• Viscous solution formed
– Gelatinization of starch
• Stable starch molecules disintegrate
– Enzyme attack begins
– Saccharification
• Fermentable sugars formed
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Brewing overview
Source: Rath
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Lautering
• Filtration process to separate the soluble malt
liquid called wort and the rest of solid grains
• The fraction of fermentable sugars in the wort
is called extract
• Filter agent are the husks of the
malt
• More water can be added to
increase the extraction
Source: Huppman
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Brewing overview
Source: Rath
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Boiling
• Boiling assures:
– Evaporation of water thus extract increase
– Coagulation of unwanted proteins
– Formation of color and aroma substances
– Isomerization of α-acids into soluble iso-α-acids
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Brewing overview
Source: Rath
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Fermentation
• The cold wort is transferred to the
fermentation cellar
• The wort is then called young beer once the
yeast is “pitched” and the fermentation
process starts
• Yeast are eukaryotic unicellular fungi used in
the industry for brewing and baking
• The yeast used for brewing beer is from the
Saccharomyces family
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Yeast metabolism
• Yeast is able to do both respiration and
alcoholic fermentation
• Wort aeration is done
at the beginning to
assure yeast growth
• After oxygen is
consumed yeast starts
forming ethanol
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Yeast metabolism
• Ethanol and CO2 are the main products of
alcoholic fermentation
• Other by-products IMPORTANT for the flavor
and aroma profile of the beer are also formed
mostly during lagering
• Such as:
• Aldehydes
• Higher alcohols
• Esters
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Yeast metabolism
• It is important to check the actual state of the
yeast
• For this two parameters are controlled:
– Vitality: physiological state of the yeast
how active is my yeast?
– Viability: rate of dead cells in the mixture
 how alive is my yeast?
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Brewing Yeast
• Two types of brewing yeast
– Top Fermenting
• Top fermentig brewing yeast
is from the species
Saccharomyces cerevisiae
• Can both reproduce sexual
and asexually
•Wanted in the brewing
process is a diploid asexual
reproduction
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Brewing yeast
– Bottom fermenting
•Species S. carlbergensis is an
hybrid of S. cerevisiae and S.
monascensis
• Is aneuploid, has a complex
and unusual chromosome
number
• Lost the capability to do
meiosis thus reproduce sexually
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Budding
• Sporulation has to be repressed so that no
mutants and no unwanted products are
formed
• To do so yeast has to grow
under normal optimal
conditions
• Yeast then multiplies by
budding
Source: www.braulots.de
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
Fermentation types
• Top fermenting
 Fermentation follows
more rapidly at higher
Temp. 13-19°C
 High content of
fermentation byproducts so stronger
flavors
Ales, Stout, Kölsch,
Wheat beer
• Bottom fermenting
 Fermentation follows
slowly at lower Temp.
10-14°C
 Lower content of
fermentation byproducts so plainer
flavor
Pilsener, Lager, Bock beer
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012
The Cayman Islands Brewery
Thank you for your
attention…
Cheers!
© The Cayman Islands Brewery, Cecilia Cruz Palma
“The Science of Brewing” STEM Carib 2012