Hygiene for Craft Brewers. A Fleeting Visit. Malcolm Swalwell. March

Transcription

1 Hygiene for Craft Brewers A Fleeting Visit March Malcolm Swalwell

2 Presentation Scope CIP- Focused Why Clean? Brewing Hygiene Factors Water Quality Substrates and Equipment Design Soil Components Detergents & Cleaning Programs Sanitisers

3 Hygiene Management Why Clean and Sanitise at all? Beer-Contamination Risk Management Microbial Chemical Physical Maximising Equipment Efficiencies Brand Protection Consumer Safety and Loyalty Stay in Business and Grow

4 Hygiene Management Why Clean and Sanitise at all? Beer-Contamination Risk Management Microbial Chemical Physical Maximising Equipment Efficiencies Brand Protection Consumer Safety and Loyalty Stay in Business and Grow

5 Brewing Hygiene Factors

6 Brewing Hygiene Factors Water Quality For Cleaning & Sanitising Operations Hardness Scales, Precipitates, Scums Excess Alkalinity Can negatively affect some sanitisers High Chlorides Increased stainless steel corrosion potential in hot neutral- acidic environments and/or low-no flow areas. Elevated organic content Precipitate formation, Sanitiser Deactivation

7 Brewing Hygiene Factors Water Quality Parameters for Cleaning & Sanitising Operations Parameter Units Suggested Target Comments Taste & Odour Aesthetically undetectable Colour TCU </=15 Drinking Water Quality especially for final rinsing of process-contact surfaces. ph Low ph (ie acidic) water will cause corrosion issues. Total Hardness ppm (as CaCO3) </= 100 Excess will contribute to scaling. Total Alkalinity ppm (as CaCO3) </= 100 Excess bicarbonate can lead to scale formation. Chloride ppm (Cl - ) </= 150 </= 50 ppm recommended for SS304, </= 150 ppm for SS316. Sulphate ppm (as SO 4 2- ) < 250 Iron ppm (Fe) </= 0.1 Excess can cause brown staining issues. Manganese ppm (Mn) </= 0.05 Excess can cause staining issues. Silica ppm (as Si 4 - ) < 10 Excess can lead to scale formation upon drying. Copper ppm </= 1.0 Excess can cause staining issues. Hydrogen Sulphide ppb Aesthetically undetectable Suspended Solids ppm Zero More than 1 ppm causes visible turbidity. Total Dissolved Solids ppm </= 500 Turbidity Nephelometric </= 5 COD ppm (O2) Zero A measure of organic load. Excess can contribute to scale formation and may support pitting corrosion in combination with elevated chlorides. (Adapted from Wershofen, 2011)

8 Brewing Hygiene Factors Substrates - Material Compatibility Considerations Stainless Steel (ie 304 grade or better) is great, however care is still required, particularly with regards to acid cleaning in combination with elevated chloride levels and heat. Mild Steels are stable to alkalis, however they are readily attacked by acids and chlorinated alkalis unless the formulations contain inhibitors. Soft Metals (eg Aluminium, Brass etc.) require special consideration, and often corrosion inhibited and/or milder detergents are needed. Polymers and Rubbers require additional considerations. Whilst most offer good detergent compatibility/ resistance, there are exceptions.

9 Brewing Hygiene Factors Brewhouse Soil Components Starch residues (mash & lauter tun) Denatured proteins Tannin/protein residues formed during mashing, boiling (hot break) and wort cooling Hop Residues Caramelised Sugars Sugar/amine (Maillard reaction) residues Scales based mainly on Ca-oxalate, with PO 4 3- & SO 4 2- (especially on heat transfer surfaces) The basis of Beerstone

10 Brewing Hygiene Factors Cellar Vessel Soiling Tannin/protein residues Sugar/amine (Maillard) residues Hop Resins Yeast deposits Beerstone Calcium oxalate (+ carbonate, and a little phosphate & sulphate) Typical Wort: ppm Ca Oxalate Typical Beer: 8 20 ppm Ca Oxalate From the Brewhouse through to Packaging, calcium oxalate can be expected to slowly precipitate out and coat process-contact surfaces. It is caustic insoluble Carbon Dioxide (CO 2 )

11 Brewing Hygiene Factors Fermenter Soiling Tannin/protein residues Sugar/amine (Maillard) residues Hop Residues Yeast deposits Beerstone Calcium oxalate (+ phosphate & sulphate) Carbon Dioxide (CO 2 ) Yeast cells tend to form clumps via a calcium bridging process. Note the brown tannin/protein deposits on the clumps in the yeast ring.

12 Brewing Hygiene Factors Protein Structure NATIVE PROTEIN CONFIGURATION DENATURED PROTEIN HEAT, ph and/or ENZYMES The unfolded structure exposes more binding sites (e.g hydrogen bonding groups) and is more likely to combine with other molecules, including phenolics, resins, sugars & other proteins (leading to the formation of larger, insoluble structures). Soil tenacity is further increased when denatured proteins combine with minerals.

13 Brewing Hygiene Factors Brewery Soil Characteristics Component Example Water Solubility? Heat Effects Detergent Ease of Removal Organic Carbohydrates Sugars, Starches Some Caramelisation Easy - Hard Alkali +/- Tannins, polyphenolics Hop Resins No Fixes Soil Moderate - Hard Oxidant Proteins Inorganic Monovalent Salts Hot Break Material Potassium Chloride Some Denatures Moderate - Hard Yes None Hot Water Easy Beerstone Calcium Oxalate No Fixes? Moderate Acid or Calcium Chelated Alkali Water Scale No Precipitation Moderate Carbonate

14 CIP Basics

15 CIP Basics Generalised 5-Step Cleaning & Sanitising Process Step Pre-rinse Wash Intermediate Rinse Sanitise Function Loose, gross soiling removed and/or softened. Reduces demand on the detergent. Detergent application with added energy; to separate the soil from the surface, rendering it into a removable state. Removes dissolved, suspended, softened & loosened soils, as well as chemical residues. Reduce surface microbial population to a process-ready (not sterile) level. Post Rinse Removes sanitiser residues (Optional depending on the sanitiser used, and company/brewer s/country s policies)

16 CIP Basics Action CIP Golden Rule If the hydraulics aren t right, nothing else matters!

17 CIP Basics Action CIP Rule-of-Thumb Pipeline Flow Rate 1.5 m/sec minimum, up to 2.0 m/sec Guarantees turbulent flow which ensures adequate physical scrubbing at internal pipe surface.

18 CIP Basics Hygienic Design Flaws in Line Circuits

19 CIP Basics Tank CIP Factors For a continuous vessel CIP process a target of ~30L per minute per metre circumference of the tank (~0.08 L/s/m 2 of tank wall to be cleaned) is targeted. This provides a suitable thickness of CIP solution to provide sufficient volume and mechanical action from a closed film of cleaning solution running down the tank walls.

20 CIP Basics Some Mistakes in Tank CIP Spray Shadows Ponding Insufficient Spray Time

21 CIP Basics Internal Kegwashing Clean kegs are critical to the quality of draft beer. CIP processes similar to that used in cellar tank cleaning are normally used, albeit with temperature. If not cleaned properly, beerstone/tannin deposits can develop inside kegs. This is especially true for kegs holding unfiltered beer. Beer-spoilers can hide underneath these layers.

22 Brewing Process Detergents and CIP Programs

23 BPD and CIP Programs Materials Typically used in Alkaline Detergents Alkali Sources Caustic Soda/Potash Alkaline Silicates Trisodium Phosphate Carbonates Sequestrants Condensed Phosphates Phosphonates Polymers (eg Polyacrylates) Gluconate/Glucoheptonate Chelants Aminocarboxylates (eg. EDTA) Detergency Properties: Organic Dissolving Power Protein Hydrolysis Emulsification Fat Saponification Water softening Soil dispersion Antiredeposition Emulsification Scale inhibition Water softening Scale stripping (eg Beerstone) Mineral deposit control

24 BPD and CIP Programs Alkali-Boosting Oxidants Chlorine Donors and Active Oxygen Donors Oxidative cleavage of protein peptide bonds and sulphide bridges O = -[- H N C H R 1 H C N H C H R 2 C O -]- Peptide Bond S S Sulphide Bridge Normally used in conjunction with alkalies to remove particularly stubborn (eg burnt-on or polymerised) soil residuals on either a maintenance or remedial basis. Active oxygen donors possess an additional physical scrubbing action via oxygen bubble release.

25 BPD and CIP Programs Caustic/Carbon Dioxide Reactions 1) 2NaOH + CO 2 Na 2 CO 3 + H 2 O Sodium Carbon Sodium Water Hydroxide Dioxide Carbonate (Caustic) 2) Na 2 CO 3 + CO 2 + H 2 O 2NaHCO 3 Sodium Bicarbonate These reactions remove CO 2 gas from inside cellar vessels (even after a good blowdown), potentially leading to vacuum formation and possible tank implosion, unless the vessel is vented to atmosphere and/or other allowances are made during caustic CIP.

26 BPD and CIP Programs Carbon Dioxide/Caustic Reactions

27 BPD and CIP Programs Materials Typically used in Acid Detergents Mineral Acids Phosphoric, Nitric, Sulphuric, Sulphamic & combinations Short Chain Organic Acids eg Citric, Glycolic, Formic, Acetic, Lactic, MSA, Solvents Corrosion Inhibitors Detergency Properties Beerstone removal & mineral deposit control Some protein hydrolysis Can enhance stone removal speed of phosphoric, and improve overall sulphuric/nitric detergency. Some function as Acidulants (ie Provide biocidal/static effects) Assists removal of organics Substrate protection

28 BPD and CIP Programs Surfactants - Typically used in most Detergents Tail (Oil-loving) Head (Water-loving) Surface wetting and crevice infiltration Soil penetration, emulsification, dispersion and antiredeposition Determines foam characteristics of the detergent use-solution. Surfactants make water wetter! Unwetted Caustic >72 mnm Water 72 mnm Milk mnm Beer mnm Target <40 mnm Adapted from Schoorens, 1982

29 BPD and CIP Programs Example Brewery CIP Programs 3-Step - Hot 1. Hot Rinse (10-15 min) 2. Wash with hot caustic detergent (2-3% w/v NaOH/55-85 C/20-45 min) 3. Hot Rinse (10-15 min) AREAS OF USE Brewhouse Vessel and Wort Lines Wort Cooler Internal Filler (& Filler Buffer Tanks) Internal Kegwash 5-Step - Ambient 1. Blowdown or Vent (CO 2 removal) 2. Rinse (10-15 min)* 3. Wash - Caustic (2% w/v NaOH) or Acid (2% v/v) for 20 min 4. Rinse (10-15 min) 5. Sanitise (1-2% v/v Acid-Fatty Acid/30 min or 150 ppm PAA/15 min) 6. Rinse (10 min) (* Step 2 often omitted for FV CIP; and a sacrificial, 0.5-0/9% w/v NaOH preflush used instead.) A well chelated, caustic detergent suggested for small-medium craft brewing CIP operations unless periodic acid use is planned. AREAS OF USE Filters Fermenters (FV s) Lagering Vessels & BBTS Times are only suggested. They will vary widely depending on the vessel being processed as well as the CIP set capabilities, especially if burst routines are available.

30 Craft Brewery CIP Sanitisers

31 CIP Sanitisers Why Sanitise? Step Pre-rinse Wash Intermediate Rinse Sanitise Function Loose, gross soiling removed and/or softened. Reduces demand on the detergent. Detergent application with added energy; to separate the soil from the surface, rendering it into a removable state. Removes dissolved, suspended, softened & loosened soils, as well as chemical residues. Reduce surface microbial population to a process-ready (not sterile) level. Post Rinse Removes sanitiser residues (Optional depending on the sanitiser used, and company/brewer s/country s policies)

32 CIP Sanitisers Why Sanitise? Step Pre-rinse Wash Intermediate Rinse Sanitise Function Loose, gross soiling removed and/or softened. Reduces demand on the detergent. Detergent application with added energy; to separate the soil from the surface, rendering it into a removable state. Removes dissolved, suspended, softened & loosened soils, as well as chemical residues. Reduce surface microbial population to a process-ready (not sterile) level. Post Rinse Removes sanitiser residues (Optional depending on the sanitiser used, and company/brewer s/country s policies)

33 CIP Sanitisers Hot Water Sanitation Pitfalls: Water scale formation/soil bake-on and associated insulation effects. Equipment wear and tear. High energy input Positives: No chemical residues or storage issues Conduction effects Detergent Clean Rinse Sanitize C, Min. Rinse (Try googling the A 0 concept)

34 CIP Sanitisers Peracetic Acid Advantages Broad spectrum Excellent low T performance Not considered corrosive to SS and Al (excessive chloride levels aside) Environmentally sound No-rinse possible No foam Disadvantages Moderate cost in-use Excessive residuals can taint Operator safety Yellow metal & mild steel corrosion Aggressive to some rubbers Soil deactivation Mixed Peracids have improved fungicidal activity over PAA.

35 CIP Sanitisers Acid-Fatty Acid Advantages Broad Spectrum Good beer compatibility profile Low SS Corrosion Descaling effects Good Reclaimability Good Water Hardness Tolerance Low foam Suits CIP Non-persistent in biological effluent treatment systems (due to activity loss as ph lifts) Disadvantages More expensive in terms of cost per litre, but full reclaimability makes them cost competitive in practice. Longer contact times required compared to peracids.

36 CIP Sanitisers Acid Anionics Advantages Descaling ability Rapid activity against most organisms Good water hardness tolerance Low corrosion risk on most processing equipment Non-persistent in biological effluent treatment systems (due to activity loss as ph lifts) Disadvantages May foam too much for CIP Often have a high P content Beer haze risk Low T performance? Acid-fatty acid detergent/sanitisers are much more prevalent these days than acid-anionics in the larger breweries for cellar equipment and line CIP.

37 CIP Sanitisers Suggested Sanitisers for Specific Application Areas in Craft Brewing Area of Use Brewhouse Vessel, Wort Line & Wort Complexing Equipment CIP, Cellar Vessels And Beer Transfer Equipment. Hot Water Sanitiser If reclaiming: Acid-Fatty Acid. If not: Peracetic Acid/Mixed Peracids Flexible Hoses, Key Pieces, Removable Fittings, Soak Tanks, Filler Externals, Environmental Sample Ports Internal Filler CIP Rinse Water Treatment Acid-Anionic, QAC, or Peracetic Acid (PAA) Alcohol, Acid-Anionic, PAA Hot water, PAA Chlorine or Chlorine Dioxide

38 CIP Sanitisers Hygiene Program Monitoring Periodic Visual Inspections Seeing is believing, and don t forget the nose! Black lights can help. Look for scale or burn-on on heat exchange surfaces. Check for yeast ring and dome residues in fermenters. Look for brown pond or tide marks in cellar vessel cones. Check for blind spots or CIP shadow areas inside tanks. Look around manhole covers and inspection door seals. Check volume gauge lines. Watch your flexible hoses. Check COP tanks regularly

39 Hygiene Management Why Clean and Sanitise at all? Beer-Contamination Risk Management Microbial Chemical Physical Maximising Equipment Efficiencies Brand Protection Consumer Safety and Loyalty Stay in Business and Grow

40 Thank You Bibliography Knettel, K. One Page regarding Tannin Removal 2012 Ecolab Rouillard, C. The Chemistry of Cleaning 1994 Schoorens, J. Acid Cleaning & Related Disinfection in Breweries 1982 The Brewer, January, pp Wershofen, T One Page Regarding Water Quality for Cleaning Solutions 2011 Ecolab