3. lauter turn false bottom to lautering machines

Manometer Gauges

• Definition: Manometer gauges measure the pressure differential between fluid pressure above and below the grain bed.

• Function: Drying liquid from below the grain bed creates a partial vacuum. The level difference indicates how hard the wort is being pulled through the grain bed.

• Modern Replacement: Due to clogging issues, manometer gauges are often replaced by pressure discs or sensors.

Darcy's Equation

• Variables: Darcy's equation includes flow rate, viscosity, permeability, bed depth, and pressure drop across the filter bed.

• Application: The equation has been modified for mesh filtration but is not universally applicable to all types of filters.

• True or False: The statement that it applies to all filter types is false.

Watering Techniques

• Air Removal: It is important to remove air from below the false bottom before introducing the mesh, referred to as under wetting.

• Process: Warm sparge water is pumped in to raise temperature and chase down air bubbles to prevent oxidation and ensure smooth wort flow.

Mash Off Technique

• Transfer Method: Use a pump with low shear and high volume for gentle transfer from the mash mixer to the lauter tun.

• Mash Bed Distribution: Distributing the mash gently is crucial to minimize oxygen pickup and achieve a leveled grain bed above the false bottom.

False Bottom Plates

• Materials and Design: False bottom plates can be made from milled stainless steel (with slots) or wedge wire designs.

• Design Specifications:

  • Milled false bottoms typically have 8-12% free area with slots measuring 30-40mm long and 0.7-1.2mm wide.

  • Wedge wire designs can have free areas up to 18%.

• Performance Considerations: Neither design exhibits superior performance; recent fabrication advancements have led to wider acceptance of wedge wire designs.

• Functionality: Both designs only support the grain bed and do not filter; the grain acts as the filter.

Grain Bed Composition

• Layer Structure:

  • Bottom Layer: Heavy particles resting directly on the plates.

  • Middle Layer: Coarse particles (husk materials).

  • Top Layer: Fine gel-like particles that can impede flow/filtration.

• Filtration Strategy: The top fine layer may need to be cut or disturbed to retrieve wort effectively. Rakes can be manually or mechanically deployed to achieve this.

Compressible Filters

• Filter Compressibility: Both mash and lauter tun filter beds are compressible, affecting fluid flow rate.

• Ideal Thickness: Modern practices aim for a grain bed depth of around 35cm (14 inches) for optimal flow; too thick or too thin can cause issues with wort clarity and filtration efficiency.

• Adjuncts: Usage of adjuncts can complicate laundering due to higher viscosity and lack of husk materials for filtration.

Laundering Process

• Recirculation: During recirculation (for lofting), wort is pumped from below the false bottom while preventing oxygen pickup.

• Equipment Design Considerations: Ensure that recirculation returns are below liquid level to avoid hot side aeration during recirculation.

Key Considerations in Lautering

• Oxygen Pickup Prevention: Important to avoid disturbing the grain bed to prevent the formation of channels that lead to ineffective filtration.

• Clear Wort Goal: The main aim of laundering is to obtain clear wort for brewing.

• Raking Systems: Rakes can be manual or powered, and are crucial for managing the bed structure and ensuring effective filtration. Modern systems use variable speeds and programmable controls based on wort clarity and flow rates.