Cleaning and Troubleshooting of Sheet Filtrations for Wine
Rinsing and Sterilization:Unsterilized sheets should be rinsed with water or recirculated with product for a
minimum of 10 minutes prior to use.
- Hot Water Sterilization : 20 minutes at a minimum 180 ̊F
- Steam Sterilization (Stainless Steel Plates ONLY) : 20 minutes at a maximum pressure of 7 psi and a maximum temperature of 230 ̊F. Do not expose filter plates to heat in fully tightened condition. Retighten filter after cooling.
- Chemical sterilants are unreliable.
- Chlorinated or caustic chemicals may damage structure.
- Surfactants such as Quaternary Ammonium or Iodofor are difficult to rinse from the sheet matrix.
- Suggested Compatible Sanitizers:
- Sulfur Dioxide @ 1000ppm
- 5% Citric Acid Solution
- Phosphoric Acid Solution 0.1-0.2%, pH 2.0
Important Factors for Good Sheet Filtrations:
- Maintain consistent conditions of flow and pressure throughout filtration.
- Use only proper grades suggested for specific purposes. Do not mix grades within a single filtration without a diversion chamber.
- If regeneration is attempted, use only clean water below 120 ̊F in reverse direction offlow. Regeneration is most effective if done right before high differential pressure is reached; i.e. below 15-20 psi (1.0-1.5 bar). Recirculate product after regeneration in critical applications.
- Assure sheets are properly oriented in filter with creped filter sheet surface facing inlet plates and screened side marked with grade and logo facing outlet plates.
- If excess edge leakage occurs (more than 3-5 gallons per 8 hr shift), check condition of filter for proper gaskets, good lubrication, or warped plates.
- Prevent release of gas from solutions inside of filter by maintaining appropriate backpressure: for still wine 10-15psi, for carbonated beverages at least 1 atm above product equilibrium pressure. Keep filter well vented through use of the outlet at the highest available point and by bleeding the vent valves.
- Proper prefining, treatment with enzymes or prefiltrations with diatomaceous earth will usually lead to greater economy and reliability of sheet filtrations.
- Wines should not be premembrane filtered with sheets more than 24 hours before the membrane filtration. With recently blended or heavily pigmented red wines, sheet filtration may be necessary immediately prior to membrane filtration.