Brewing Science
Cleaning
Brewery Cleaning and Sanita1on
• Cleaning and sanita1on are integral parts of successful brewing
• Cleaning: removal of organic and inorganic residues and microorganisms
• Sanita1on: reduce the popula1on of viable microorganisms and prevent microbial growth
Cleaning
• Cleaning agents broadly fall into alkaline or acidic detergents; o>en with added surfactants, chela1ng agents, and emulsifiers
• Must (1) wet surfaces, (2) penetrate residue deposits, (3) hold par1cles in suspension, and (4) keep inorganic ions in solu1on
Alkaline Detergents
• Effec1vely remove organics: oils, fats, proteins, starches
• Hydrolyze pep1de bonds, breaking down proteins
• Ineffec1ve against inorganics such as calcium oxalate and can leave “beerstone”
• PBW is a good example
Alkaline Detergents • Sodium Hydroxide: “Its effec1veness in dissolving
proteinaceous soils and faTy oils by saphonifica1on is virtually unsurpassed. This makes it a natural choice for cleaning sludge off the boToms of boilers and for cleaning beer kegs. Sodium hydroxide is an acutely excellent emulsifier too. It is unrivaled in its ability to dissolve protein and organic maTer if used in conjunc1on with chlorine, surfactants, and chela1ng agents.”
• Sodium Hydroxide / Hypochlorite Solu1ons: “Caus1c/hypochlorite mixtures are par1cularly effec1ve in removing tannin deposits, but are used for a great variety of cleaning tasks. These mixtures can be used in CIP systems for occasional purge treatments or to brighten stainless steel.”
Acid Detergents
• O>en used in two step process with alkaine detergents
• Less effec1ve against soil, tannins, oils, resins, and glucans
• Remove beerstone / calcium oxalate, waterscale (Ca and Mg carbonates), and aluminum oxides
• More effec1ve against bacteria
Acid Detergents
• Phosphoric Acid: widely used to remove deposits, enhanced by acid-‐stable surfactants. Generally less effec1ve below 16 cen1grade.
• Nitric Acid: removes deposits and has biocidial proper1es, par1cularly in mixture with phosphoric acid. Also breaks down protein. Acid Cleaner #5 is an example.
Addi1ves
• Surfactants / Webng Agents
• Chela1ng Agents (EDTA, sodium gluconate, sodium tripolyphosphate)
• Emulsifiers (orthophosphates and complex phosphates)
Sanita1on
• Sani1zing or disinfec1ng agents used to reduce the level of microorganisms
• Simple physical methods include hot water or hot steam
• Chemical sani1zers range in effec1veness, temperature, and contact 1me requirements
Alkaline Sani1zers
• Chlorine: Broad spectrum germicides that disrupt membranes, inhibit glucose metabolism, and oxidize protein. Ac1ve at low temperatures, inexpensive, leaves low residue
• Quaternary Ammonium: stable and non-‐corrosive, rapid bactericidal ac1on at low concentra1ons. Efficient against gram-‐posi1ve bacteria, yeast, and mold. Ineffec1ve against gram-‐nega1ve bacteria. (Quantum)
Acidic Sani1zers • Hydrogen Peroxide: broad spectrum, beTer against gram-‐nega1ve.
• Peroxyace1c Acid: germicidal, no vapor issues or foam. Requires rela1vely high concentra1ons.
• Anionic Acids (Star San) • Iodophores: wide biocidal spectrum, equally effec1ve to all microorganisms, but may have staining problems. (IO Star)
Methods in Brewery Cleaning • Manual: “Many cra> brewers do not have the luxury of cleaning-‐in-‐place systems and have to manually clean and sani1ze their equipment. They o>en have to use so>-‐bristled brushes, non-‐abrasive pads, cloths, and handheld spray hoses for cleaning. When cleaning manually, great care must be taken to assure that brushes and equipment are cleaned to avoid cross-‐contamina1on.”
• Clean in Place
In Depth CIP
The following slides are from:
Principles and Prac.ce of Cleaning in Place Graham Broadhurst Great Lakes Water Conserva1on Conference, October 2010
CIP / SIP -‐ Defini1on
• CIP = Cleaning in Place – To clean the product contact surfaces of vessels, equipment and pipework in place. i.e. without dismantling.
• SIP = Sterilise in Place – To ensure product contact surfaces are sufficiently sterile to minimise product infec1on.
How CIP Works
• Mechanical – Removes ‘loose’ soil by Impact / Turbulence
• Chemical – Breaks up and removes remaining soil by Chemical ac1on
• Sterilant/Sani1ser – ‘Kills’ remaining micro-‐organisms (to an acceptable level)
Factors affec1ng CIP
• Mechanical
• Chemical
• Temperature
• Time
CIP Opera1on
• PRE-‐RINSE -‐ Mechanical Removal of Soil
• DETERGENT -‐ Cleaning of Remaining Soil -‐ Caus1c, Acid or Both
• FINAL RINSE -‐ Wash Residual Detergent/Soil
• STERILANT/SANITISER -‐ Cold or Hot
Typical CIP Times
Vessel CIP
Mains CIP
Pre-Rinse
10 to 20 mins
5 to 10 mins
Caustic Detergent
30 to 45 mins
20 to 30 mins
Rinse
10 to 15 mins
5 to 10 mins
Acid Detergent
20 to 30 mins
15 to 20 mins
Rinse
15 to 20 mins
10 to 15 mins
Sterilant
10 to 15 mins
5 to 10 mins
Typical CIP Temperature
• Brewhouse Vessels Hot 85°C • Brewhouse Mains Hot 85°C • Process Vessels Cold < 40°C • Process Mains Hot 75°C • Yeast Vessels Hot 75°C • Yeast Mains Hot 75°C
CIP Detergent -‐ Requirements
• Effec1ve on target soil • Non foaming or include an1-‐foam • Free rinsing / Non tain1ng • Non corrosive – Vessels/pipes, joints • Controllable -‐ Conduc1vity • Environmental
Caus1c Detergents • Advantages
– Excellent detergency proper1es when “formulated”
– Disinfec1on proper1es, especially when used hot.
– Effec1ve at removal of protein soil.
– Auto strength control by conduc1vity meter
– More effec1ve than acid in high soil environment
– Cost effec1ve
• Disadvantages – Degraded by CO2 forming
carbonate. – Ineffec1ve at removing inorganic
scale. – Poor rinsability. – Not compa1ble with Aluminium – Ac1vity affected by water
hardness.
Acid Detergents • Advantages
– Effec1ve at removal of inorganic scale
– Not degraded by CO2 – Not affected by water
hardness – Lends itself to automa1c
control by conduc1vity meter.
– Effec1ve in low soil environment
– Readily rinsed
• Disadvantages – Less effec1ve at removing
organic soil. New formula1ons more effec1ve.
– Limited biocidal proper1es -‐ New products being formulated which do have biocidal ac1vity
– Limited effec1veness in high soil environments
– High corrosion risk -‐ Nitric Acid – Environment – Phosphate/
Nitrate discharge
Detergent Addi1ves
• Sequestrants (Chela1ng Agents) – Materials which can complex metal ions in solu1on, preven1ng precipita1on of the insoluble salts of the metal ions (e.g. scale).
– e.g. EDTA, NTA, Gluconates and Phosphonates. • Surfactants (Webng Agents)
– Reduce surface tension – allowing detergent to reach metal surface.
Sterilant / Sani1ser Requirements
• Effec1ve against target organisms • Fast Ac1ng • Low Hazard • Low Corrosion • Non Tain1ng • No Effect On Head Reten1on • Acceptable Foam Characteris1cs
Sterilants / Sani1sers
• Chlorine Dioxide • Hypochlorite • Iodophor • Acid Anionic • Quaternary Ammonium • Hydrogen Peroxide • PAA (Peroxyace1c Acid) – 200-‐300 ppm
CIP Systems
• Single Use – Water/Effluent/Energy costs
• Recovery – Detergent Recovery – Rinse/Interface Recovery
• Tank Alloca1on • Number of Circuits
Single Use CIP Systems
CIP Buffer Tank
Water Conductivity Flow
CIP Return
CIP Supply
Conductivity Flow CIP Supply Pump
Temperature
CIP Heater
Steam
Recovery CIP Systems 1 x Supply – 3 Tank System
Final Rinse Tank
Water Conductivity Flow CIP Return
CIP Supply Flow CIP
Supply / Recirc Pump
Temperature CIP
Heater
Steam
Pre-Rinse Tank
Caustic Tank
CIP Return / Recirc
CIP Supply / Recirc
LSH
LSL
LSH
LSL
LSH
LSL
Temp
Recovery CIP Systems 2 x Supply – 4 Tank System – Separate Recirc
CIP Supply A
LSH
Final Rinse Tank
Water
Cond Flow
CIP Return A
Flow CIP Supply A Pump
Pre-Rinse Tank
Caustic Tank
LSH
LT
LSH
LT
LSH
LT
Temp
Caustic Recirc Pump
Temp
Acid Tank
LT Acid Recirc Pump
Cond Cond
Cond Flow
CIP Return B
CIP Supply B
Flow CIP Supply B Pump
Recovery CIP System
Single Use vs Recovery • Single Use CIP
– Low Capital Cost – Small Space Req. – Low Contamina1on Risk – Total Loss
• High Water Use • High Energy Use • High Effluent Vols.
– Longer Time/Delay – Use for Yeast
• Recovery CIP – High Capital Cost – Large Space Req. – Higher Contamina1on Risk – Low Loss
• Low Water Use • Low Energy Use • Low Effluent Vols.
– Shorter Time/Delay – Use for Brewhouse &
Fermen1ng
CIP Systems CIP Tank Sizing
• Pre-‐Rinse – CIP Flow x Time
• Detergent – Vol of CIP in Process Mains & Tank + Losses
• Final Rinse – Flow x Time – Water Fill
CIP Systems Prac1cal Points
• CIP Supply Pump • Recircula1on
– Shared/Common with CIP Supply, or – Dedicated to Tank
• CIP Supply Strainer • CIP Return Strainer • CIP Tank Connec1ons
Types of CIP
• VESSEL CIP -‐ Sprayhead Selec1on -‐ Scavenge Control
• MAINS CIP -‐ Adequate Velocity -‐ Total Route Coverage
• BATCH/COMBINED CIP -‐ Complex Control -‐ Time Consuming
Vessel CIP
• Flow of CIP fluid from CIP supply to vessel sprayhead
• Internal surfaces cleaned by spray impact / deluge
• Return from vessel by CIP scavenge (return) pump
CIP Return
CIP Supply
CIP Scavenge Pump
Process Vessel
CIP Gas pipe
Isolate from Process
Vessel CIP -‐ Sprayheads
• Sta1c Sprayballs – High Flow / Low Pressure
• Rota1ng Sprayheads – Low Flow / Medium Pressure
• Cleaning Machines – Low Flow / High Pressure – High Impact
Vessel CIP – Sprayballs • Advantages
– No moving parts – Low Capital Cost – Low pressure CIP supply – Verifica1on by Flow
• Disadvantages – High Water & Energy Use – High Effluent volumes – Limited throw – Small vessels – Spray Atomises if Pressure High – No impact -‐ long CIP 1me and/or high
detergent strength – Higher absorp1on of CO2 by caus1c
Vessel CIP – Rotary Sprayheads • Advantages
– Not too Expensive – Some Mechanical Soil Removal – Lower Flow – Reasonable Water/Energy Usage – Reasonable Effluent
• Disadvantages – Moving parts – Limited throw – Small vessels – Possible blockage
• Rota1on verifica1on • Supply strainer
Vessel CIP – Cleaning Machines
• Advantages – High impact, aggressive
cleaning – Good for heavy duty
cleaning – Low water/energy use – Low effluent – Effec1ve in large vessels – Lower absorp1on of CO2 by
caus1c – Lower Flow means smaller
Pipework
Vessel CIP – Cleaning Machines
• Disadvantages – Expensive – Moving parts – High pressure CIP supply pump
– Possible blockage • Rota1on verifica1on • Supply strainer
Mains CIP
• Flow of CIP fluid from CIP supply, through process pipework and back to CIP set
• The en1re process route must see turbulent CIP Flow
• No/Minimal Tees/dead legs
• Isolate from other process lines CIP Return
CIP Supply
Isolate from Process
Isolate from other Process routes
Process Route being CIP’d
Mains CIP Turbulent & Laminar Flow
Mains CIP Turbulent & Laminar Flow
• Turbulent Flow – Flat velocity
profile – Thin Boundary
layer – Effec1ve CIP
• Laminar Flow – Streamline flow – Velocity profile,
faster at centre – Ineffec1ve CIP
Thin Boundary Layer at pipe wall
Mains CIP
• Turbulent Flow – – Re > 3000
• Minimise Boundary layer – – Laminar layer on internal pipe wall
• Minimum CIP velocity (in process pipe) ≥ 1.5 m/s.
• Excessive velocity – High Pressure drop / Energy input
Mains CIP – CIP Flow Process Pipe dia
(mm)
Minimum CIP Flow
(m3/h)
CIP Supply / Return dia
(mm)25 2.1 2538 5.2 3850 10 5065 16 6575 24 65100 42 75125 70 100150 100 125200 170 150250 280 200300 400 200350 520 250400 700 250
Min CIP Velocity 1.5 m/s minimumBased on o/d tube to 100 mm and metric I/d above 100 mm.
Process Pipework Design for CIP
• Ensure Total Route coverage – Avoid Split routes
– Avoid Dead ends
– Avoid Tees
– Most Cri1cal on Yeast & nearer packaging
Process Pipework Design for CIP
• Isolate CIP from Process – Mixproof Valves
– Flowplates
CIP Return
Process Line – Not being CIP’d
Process Line –being CIP’d
FLOWPLATE
Physical Break between routes
Batch/Combined CIP
• Combines CIP of – Vessel/s and – Pipework in one clean
• Why ? – Pipework too large for ‘mains’ CIP e.g. Brewhouse 200 to 600 mm.
– Pipework linked to Vessel e.g. Recircula1on Loop or EWH.
Batch/Combined CIP
• Supply of a batch volume of CIP to process vessel
• Internal recircula1on of CIP within/through process vessel
• Transfer of CIP to next vessel • Pumped return of CIP batch volume to CIP set.
CIP Monitoring & Control On-‐Line
• Detergent Temperature • Detergent Strength -‐ Conduc1vity • Return Conduc1vity
– Detergent Start Interface – Detergent End Interface – Rinse Conduc1vity
• Return Flow • Recirc/Return Time • Supply Pressure
CIP Monitoring & Control Off-‐Line
• Visual Inspec1on • Final Rinse return sampling
– pH – Micro – ATP
• Vessel/Pipework swabs – pH – Micro – ATP
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