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SOP — Yeast Harvest

FUERST WIACEK Version 1.1 | Cellar — yeast brink | Frequency: per harvest (typically Tuesday before DH)

Purpose

This SOP covers harvesting yeast from a fermentation tank into the yeast brink. The brink must be CIPed before harvesting — refer to the Yeast Brink CIP SOP.

Pitching yeast into a new brew is covered in the Wort Knockout SOP.

PPE Required

  • Safety goggles
  • Gloves

Risks

Hazard Risk
Over-pressurising brink Spray of yeast or liquid under pressure
Over-harvesting Beer loss from tank — monitor sightglass continuously

Equipment

  • Yeast brink (CIPed and ready — see Yeast Brink CIP SOP)
  • Sightglass (installed between tank outlet and brink inlet)
  • T-piece on tank outlet
  • Clean sample container
  • Compressed air line

Process

1. Confirm Brink Ready

  • Brink is empty of PAA and at 0 bar pressure
  • Sightglass is installed between the tank outlet and the brink inlet
  • CIP return connection is submerged in PAA bath

2. Harvest

  1. Open the full drain valve of the tank to approximately 50% and allow yeast to flow into the brink.
  2. Vent the pressure that builds as the brink fills — open the vent valve slowly.
  3. Fill the brink completely, or stop when beer starts coming through — whichever comes first.

Warning

Monitor the sightglass continuously. Stop harvesting as soon as the flow transitions from yeast slurry to clearer liquid — this means you are pulling beer from the tank, not yeast.

3. Take Yeast Sample

When the brink is approximately 50% full, take a sample from the T-piece connection. This sample is treated as representative of the full brink contents and is used for cell count analysis.

  1. Open the T-piece side valve briefly and collect a small sample into a clean container.
  2. Close the T-piece side valve and continue harvesting.
  3. Analyse cell count as per the Cell Count SOP.

4. Close Off

  1. Once harvest is complete, close the full drain valve on the tank.
  2. Close all valves on the brink.
  3. Depressurise the line by opening the T-piece side valve briefly.

The brink is now ready for pitching — refer to the Wort Knockout SOP.

Checklist

  • [ ] Brink CIP complete — brink at 0 bar, PAA emptied
  • [ ] Sightglass installed on T-piece
  • [ ] Full drain opened ~50%, yeast flowing to brink
  • [ ] Pressure vented as brink fills
  • [ ] Yeast sample taken from T-piece at ~50% full
  • [ ] Sightglass monitored — harvest stopped before beer pulls through
  • [ ] All valves closed, line depressurised

Troubleshooting

Issue Likely Cause Action
Over-harvesting — beer entering brink Sightglass not monitored closely Stop immediately. Note approximate volume of beer harvested and inform team.
Brink pressure not dropping during vent Vent valve not fully open or blocked Check vent valve. Do not open full drain further until pressure is vented.
Yeast not flowing from tank Tank pressure too low Add a small amount of CO₂ pressure via CIP arm to push yeast toward drain.