INTRODUCTION TO BREWING AT FULLERS docx

THE BREWING PROCESSBREWING LIQUOR MASH TUN COPPER / WHIRL POOL MILL SWEET WORT CONDITIONING TANKS PARAFLOW BRIGHT BEER TANKS... Preparation of grist for the mash tun Keep husk material

INTRODUCTION TO

BREWING AT

FULLERS

• Bright Beer Tank 36

• Small Pack Quality

THE BREWING PROCESS

BREWING LIQUOR

MASH TUN

COPPER / WHIRL POOL MILL

SWEET WORT

CONDITIONING TANKS

PARAFLOW

BRIGHT BEER TANKS

The Brewing Process

• MILLING - malted barley is crushed to form a coarse

flour called grist

• MASHING - grist is added to liquor to form a porridge-like

mash This activates the enzymes, thus enabling them to solubilise the protein and starch fractions of the

endosperm

is separated from the spent solids using a mash tun

hops which impart bitterness and aroma Boiling sterilises the wort, coagulates some proteins and causes formation

of colour compounds The spent hop material along with some protein, known as trub, is removed by whirlpool

action

transported to the fermentation vessel The wort is

aerated & pitched with yeast Fermentation proceeds

until much of the carbohydrate is converted to alcohol and carbon dioxide Higher alcohols and other yeast

metabolites (for example esters) contribute to beer

flavour and aroma

BREWHOUSE

Brewing Liquor

• Water Treatment - removal of hardness by heating & acid

addition

• Direct Flavour Effects - Na + sweet (salty in excess) / Mg 2+

bitter, sour / Fe 3+ metallic / Cl - fullness / S04 2- astringency / K+ salty

• Indirect flavour effects - yeast requirements / pH / enzymes during mashing Keep calcium >150ppm Four times more

calcium than malt oxalate required

Raw Materials

Pale Ale Malt

• Malted barley

• Concentrated source of starch

• Starch consists of unbranched helical amylose

[200-400 D-glucose units linked via α−1,4-positions] AND branched amylopectin [D-glucose units linked via α-1,6 and α -1,4 links Up to 6000 glucose units]

molecules

• Barley starch granules : large granules supply most of the brewers extract (20 - 25µ) and small starch

granules (1 - 5µ)

• Barley protein : 30% glutelin (dissolves in weak

alkali)+ 37% hordein (dissolves in 80% alcohol)+ 11% albumin (dissolves in water)

• High molecular weight proteins : improve head

retention

Raw Materials

Coloured Malts & Adjuncts

• Crystal Malt - contributes colour (150° EBC colourunits)and malty / nutty / toffee / fruity notes to

London Pride, Chiswick Bitter & ESB

• Chocolate Malt - contributes colour & flavour to

London Porter

• Amber Malt - contirbutes colour (45°EBC colour

units) and sweetness and dryness to 1845

• Malted Wheat - contributes fullness and fruity notes

to Summer Ale along with more protein for head formation

Mechanical breakdown of dry goods to produce grist.

Preparation of grist for the mash tun

Keep husk material in-tact to act as filter bed during

wort recovery

• Endosperm material into small particles, grits,

which readily hydrate during mashing to reactivate the malt enzymes giving us maximum extract

• Dry milling - 4 roller mills with 2 pairs of

contra-rotating rollers

• Proportions of coarse grits (0.3mm-0.6mm

diameter):fine grits (0.15mm - 0.3mm): flour

(<0.15mm) ratios vary from 27:35:38 to 24:35:41

• Gypsum (calcium sulphate) is added to the grist as

it is produced (see liquor treatment page)

• Grist transferred via conveyor to grist hoppers

Hydrate grist and activate enzymes to form

soluble substances for fermentation

• Hot liquor (69°-71°C) comes into contact with the grist in the ‘Steels Masher’ to achieve a

mash temperature of 65°C in the mash tun

• A porridge-like mash is formed with a bed

depth of 1.5-2.0m in the mash tun

• The mash tun has a false / slotted floor 5mm from the base of the vessel and the mash sits

on this for 55mins The false floor is flooded with hot liquor before mashing starts to

remove the air

• During this period starch is degraded by

amyloytic enzymes forming sugars (primarily

5.4 62°C

Alpha –

Amylase

Random hydrolysis ofstarch to form

dextrins

5.7 67°C

Extract -L°/Kg and %

w/w

• EXTRACT - amount of substances in solution from raw materials under controlled conditions (IOB L°/Kg or EBC %w/w)

• %w/w sucrose = °Plato or °Brix (approximately

Starch Degradation

• Gelatinisation - starch granules swell with water

and finally burst viscous/sticky solution which can

be directly attacked by enzymes

• Liquefication - rapid reduction of viscosity by amylase attacking gelatinised amylose and

α-amylopectin

attacks and β-amylase attacks new non-reducing ends to form maltose

IODINE TEST

• Blue = gelatinised starch / large dextrin's

• Violet / Red = Medium size dextrins

• Iodine normal = small dextrins / maltotriose /

maltose / glucose

Wort Separation

The sugar solution, wort, is separated from the grains

• Filtration process with the husk as the filter bed

• Recirculation - bed settling and wort clarification

• 1st stage - first wort or strong wort collection (high in extract)

• 2nd stage - sparging the spent grain with liquor to remove extract

• Last runnings - 1004° (0.5°P) Leave polyphenolic & tannin material from husks

• Spent grains - 70% water[28% protein; 8.2% fat; 41% N-free extract; 17.5% cellulose; 5.3% inorganic material]

• Extract recovery 98-100%

• Turn around time 3 hours

Hops - Humulus lupulus

The Hop Plant

• Perennial, dioecious climbing plant belonging to the Cannabis family; only female plant bears hop cones

• Grown in temperate climates eg UK, NZ, North USA

• Hop cone (or flower) contains 14 - 21% hop resin which houses the α-acids (humulone; cohumulone;adhumulone) which are needed by the brewer

• Hop cone contains 0.5-1.5% essential hop oils

which give beer its characteristic hoppy aroma

• Hop pellets are concentrated from hop cones and used at Fullers

• Different hop varieties offer different characteristics

to the beer eg floral, spicy, woody, citrus notes

• Some varieties used at Fullers include Target,

Hop Chemistry

• The α-acids are isomerised (chemically changed) during wort boiling to give iso-α-acids (isohumulone;isocohumulone; isoadhumulone)

Use Of Hops

• Kettle hopping - added at the start of the boil to

covert the non-bitter α-acids to bitter iso-α-acids

• Late Hopping - aroma hops added late to boil /

remaining oils give late hop characters

• Dry hopping - addition of hop cones directly to the cask during racking

Wort Boiling

• Traditionally a copper vessel used

• Now we have two 520 HL stainless steel coppers where the wort is boiled

• The wort is continuously pumped from the vessel to

an external calandria (called the EWB=external wortboiler) for heating & returned to the vessel

tangenitially (at 90°)

Chemisty

• Formation of bitter compounds

• Wort sterilisation

• Precipitation of calcium phosphate & proteins

causing the pH to drop from 5.4 to pH 5.2

• Evaporation and hence concentrate the wort

• Inactivation of enzymes

• Formation of flavour active compounds

• The wort pumping is stopped, and the wort is

allowed to spin freely for 20 minute

• As it loosses momentum the heavier ‘trub’ material settles in the trough at the base of the copper

• Trub material is composed of hop materail which protein, polyphenol & tannins have become adhered

• When the wort is run-off for cooling and pumping to fermentaion vessel it is drawn through a pipe above the trough so the trub is left as a waste material

• Longer stands allow more SMM (sulphur methyl

methionine) from malt to be converted to DMS

Wort Cooling

Quick cooling of the wort via a paraflow

• This cooling removes the cold break (small

particles (<0.5um) of protein/ polyphenol / hop) and prepares the wort ready for yeast addition

• The paraflow is a heat exchanger made up of 100 plates with chilled liquor (<10°C) on one side and hot wort on the other

• This large surface area allows the heat from the wort to heat up the liquor (thus cooling the wort

itself) which returns to the liquor tanks for the next day brewing

• The wort is cooled to 17°C ‘en route’ to the

fermentation vessel

FERMENTATION

Conversion of wort sugars to form alcohol & other

flavour components

100 g Maltose + 0.5 g Amino acid 5 g Yeast +48.8 g

Ethanol +46.8 g CO 2 + 50kCal Energy

• Wort is made up of 70% Maltose; Maltotriose 18%;

Sucrose 5%; Glucose 5%; Fructose 2%

• Pitching (adding) viable yeast at 10 million cells per ml is added to the wort from the paraflow to the fermentation vessel

• Air is added in-line or directly into fermentation vessel at the start of fermentation this is so the yeast can for

materials needed for new cell membranes & walls

• The air is switched off and anaerobic metabolism by the yeast of the wort sugars continues to form alcohol &

carbon dioxide

• Initial lag phase then exponential growth until alcohol &

Carbohydrate Metabolism

• Sequence of sugar uptake :(a) glucose, fructose, sucrose (b) maltose (c) maltotriose

• Anaerobic respiration via the glycolytic or Embden

-Meyerhof Parnas pathway

• A small proportion of acetyl Coenzyme A is formed

during the fermentation from pyruvate via the TCA cycle TCA cycle also yields oxo acids & NAD Acetyl Co A is important in production of fats & esters and amino acid synthesis

• Without oxygen, fatty acids & sterols can not be

synthesised to form membranes & yeast can not tolerate the ethanol concentration so growth ceases

• Acetyl CoA + alcohol ester + Co A

e.g Acetyl CoA + ethanol ethyl acetate + Co A

Nitrogen Metabolism

• Amino acids in wort used for protein synthesis / DNA & other cellular structures

• Arginine; aspartic acid; asparagine; glutamic acid;

glutamine, lysine; serine; threonine can be used only at start of fermentation Other amino acids are made by the yeast cell During this production the equivalent amount of oxo acid is made by the glycoltic pathway to accept NH2.

• Nitrogen deficiency but oxo acid production continues Reduced to alcohol.

• Production Of Flavour Compounds

• Amino acid deamination (removal of amino NH2 group) and decarboxylation (removal of CO2) higher alcohols are formed

e.g leucine pentanol + ammonia + CO2

• intermediate products are aldehydes which are also

flavour active

e.g valine oxovalerate isobutyraldehyde

isobutanol

SUGARS

PYRUVATE

ACETYL CoA ACETOLACTATE

DIACETYL ISO BUTANOL

KETO ACIDS

PENTANE DIONE

SO 2 & H 2 S

ACETALDEHYDE

ETOH

GLUCOSE-6- PHOSPHATE

FRUCTOSE-1,6-PHOSPHOENOL PYRUVATE

Beer Maturation /

Conditioning

Natural refinement of beer flavours

• After fermentation all Fullers beers are centrifuged to remove any excess yeast

• Beers for kegging, canning or bottling go to

CONDITIONING at 10°C

• Beers for cask go to MATURATION at 6°C

• En route to these individual departments a small

amount of yeast is re-introduced in to the beer stream

• A period (5-7 days) of warm conditioning or secondary fermentation is allowed in which the yeast reduces

buttery flavours (due to the compound diacetyl) and modifies green, grainy flavours to more rounded malty notes along with production of carbon dioxide

• Beers from maturation are then ready for cask racking

• Beers in conditioning tanks are then cooled rapidly to

END PROCESSING

End Processing

4 BBT

3 FILTRATION

1 CONDITIONING TANK / RACKING TANK

Cask Racking

Beer from maturation tanks is pumped to the racking

tank for filling into cask

• Fermentable extract remains in this beer (or honey

primimgs for HoneyDew is added) and yeast (0.25 - 2.0 million cells / ml)

• Run into racking tank (auxiliary finings for protein

removal is added)

• Casks filled directly or via racker under counterpressure from a smaller tank, the Jack Back

• Chiswick Bitter & ESB are dry hopped (a nugget of

compressed hop flowers is added to each container)

• Isinglass finings - collagen net which traps the

negatively charged yeast and brings it into the belly of the cask after 24-28 hours is added as the cask is filled

• Cellar - 13°C for secondary fermentation to proceed which conditions’ the beer (3-5 days) CO2 escapes via soft spile

• Filter sheets:

– Coarse 2.5 - 5 µm

– Medium 2.5 - 3.5 µm

– Fine 1.2 - 1.8 µm

3 Filtration

Aim : to clarify the beer by removing yeast cells,

non-biological haze particles and non-biological particles in some cases

Basic Principles : unfiltered liquid enters the filter with

a higher pressure than the clear filtrate on the outlet side which drives the process

• Filter Mass - cellulose pads on a hollow frame

structure through which beer is forced

• Powder filtration - slurry of kiesulguhr pumped onto filter mesh as precoat then beer + kieselguhr

pumped through under pressure & recycled until clear Then beer + ‘bodyfeed kieselguhr’ pumped through filter

• Filter sheets - cellulose, cotton, kieselguhr or perlite sheets on a hollow framework Depth filtration &

Adsorption filtration

• Membrane filtration -filtrate passes via pores

0.01-Plate & Frame

4 B.B.T (Bright Beer

Tank)

QUALITY CONTROL

• Alcohol - blend or use deaerated liquor

• Colour - caramel & malt extracts

• pH

• Sensory perception

• Bitterness - blend or iso-/ tetra hop additions

• Flavourings - fruit essences for example

• Carbonation / Nitrogenation - direct injection / hydrophobic membrane technology

• Propylene glycol alginate (PGA) - 30-50 g/Hl protects beer foam from lipid damage &

enhances foam stability

Small Pack Quality

-physical damage, colour

quality, bar code

crown corks & coating

CANS (IOB methods 13.2-13.7)

• Visual inspection incorrect pallet formation, physical damage, missing cans, foreign cans, bar code, print & decor quality, excessive / defective external lacquer)

-• Check internal lacquer integrity (& external lacquer Contamination of can ends

5 Bottling - filling

• Bottle cleaning: presoak; 60 - 85°C hot caustic

baths; hot caustic rinse; hot water rinse; cold water rinse & then demineralised water rinse Inspection (previous slide)

• Vacuum filling : 0.93 - 0.98 bar under pressure in bottle so liquid is sucked in Used for milk, wine,

• Adhesive - too thick then time to removal; too thin not properly stuck Can be starch, dextrin, casein, vegetable based.

6 Canning - filling

• Advantages : unbreakable, lighter, no return, stable, easy opening, good space utilisation, advertising space, impermeable to light, pasteurised in

• Best before date - laser application to base

• Can rinsing - depalletised & rinsed to remove dust

• Filling sequence : filling element lowered onto can & forms air tight seal; pressed against can; evacuated and counter pressurised with CO2; beer flows from 14/16 small tubes in filler valve due to differential pressure between filling chamber and can; release pressure and gentle discharge to avoid spilling.

• Can sealing : stage 1 - rest lid on can in carousel in

7 Pasteurisation

AIM: prolong shelf life of beer/cider by inactivating all

micro-organisms which could cause chemical changes

to product

•Shelf-life also prolonged by low pH; ethanol; CO2 & certain hop compounds

•Lethal effect on organisms from 53°C

•1 PU = the lethal effect produced by holding for one minute at 60°C Increases tenfold for every 7°C rise in temp