Problems on this page:
Temperature not holding
Hits OEE: Quality
Symptoms: The fermenter runs warmer or colder than the fermentation profile.
Glycol supply temperature or flow low
Check the glycol chiller and the supply pressure to the tank jackets.
Jacket valve sticking or not opening
Check the jacket solenoid or control valve and its signal.
Temperature probe in the wrong place or drifting
Check the probe position and compare it with a reference.
Too many tanks crash cooling at once
Stagger crash cooling so the glycol system keeps up.
Prevention: Tank temperatures trended against the profile.
Fermentation slow or stuck
Hits OEE: Quality
Symptoms: Gravity drops slower than usual or stops before the target.
Pitching rate or yeast health low
Check the yeast count and viability before pitching.
Wort oxygen too low at pitching
Check the aeration or oxygenation at the wort line.
Fermentation temperature too low
Check the tank temperature against the profile.
Wort composition different
Check the brewhouse records for the brew.
Prevention: Gravity measured daily during fermentation.
Pressure or vacuum problems
Hits OEE: Availability
Symptoms: The tank over-pressures, or a vacuum forms when emptying or cooling.
Spunding valve set wrong or stuck
Check the spunding valve setting and clean it.
Pressure relief or vacuum valve blocked by foam or yeast
Clean and test the relief and vacuum valves; a blocked valve can damage the tank.
Tank emptied or cooled without venting
Open the vent or supply gas when emptying or crash cooling.
Blow-off line blocked
Clean the blow-off line after every fermentation.
Prevention: Relief and vacuum valves tested on a fixed schedule.
Yeast harvest problems
Hits OEE: Quality
Symptoms: Harvested yeast is low in volume or viability, and the next fermentations suffer.
Cone cooled too late
Cool the cone at the point in the profile the recipe sets.
Harvest done too late after fermentation
Harvest at the planned time, before the yeast sits warm in the cone.
Yeast stored too warm
Check the yeast storage tank temperature.
Too many generations reused
Follow the generation limit and bring in fresh yeast on schedule.
Prevention: Yeast viability tested at each harvest.
Contamination found in the beer
Hits OEE: Quality
Symptoms: Lab tests find bacteria or wild yeast in the fermenting beer.
Tank cleaning or sanitising incomplete
Check the cleaning and sanitising records and the spray device.
Valves and sample points not cleaned
Clean and sanitise sample valves and racking arms.
Gaskets damaged or old
Replace damaged gaskets where product can collect.
Contaminated yeast pitched
Check the yeast source and its lab results.
Prevention: Microbiology results reviewed per tank.
Foaming over during fermentation
Hits OEE: Availability
Symptoms: Foam overflows through the blow-off, losing beer and blocking lines.
Tank filled above its working volume
Leave the headspace the tank design needs.
Fermentation temperature too high early on
Check the temperature profile at the start.
Wort with high foam potential
Check the recipe and consider antifoam where the product allows.
Blow-off line too small
Check the blow-off design.
Prevention: Foam-overs recorded per tank and brand.
Cleaning cycle failing
Hits OEE: Availability
Symptoms: The tank is not clean after its cleaning cycle.
Spray ball blocked or not turning
Check the spray device.
Caustic weakened by CO2 in the tank
Vent CO2 before caustic cleaning or use an acid cleaning program.
Cleaning return pump not keeping up
Check the return pump so the tank does not flood.
Cleaning time cut short
Check that each step runs fully.
Prevention: Cleaning records reviewed per tank.
Tank level or gauge wrong
Hits OEE: Quality
Symptoms: The tank volume reading does not match what was transferred in or out.
Level sensor setup does not match the tank
Check the tank dimensions and offsets entered in the level sensor.
Foam affecting the reading
Read the level after the foam has settled.
Tank top pressure not compensated
Check that the level measurement compensates for the head pressure.
Sensor fouled with yeast or beer stone
Clean the sensor during the tank cleaning cycle.
Prevention: Tank volumes reconciled with transfers monthly.
Guidance only. Always follow lockout/tagout and your site's safe-work procedures, and verify against OEM manuals before acting.
Related equipment guides: brewhouse · beer filter · chiller · CIP system · keg washer · wine press
Stop the same fault coming back
Recurring fermentation tank stops usually trace to a cause you cannot see by hand. The partner we recommend is Fabrico: it tracks OEE and downtime live from PLCs, IoT sensors or AI cameras; where cameras are fitted, the video of a stop sits next to its machine data so the cause can be reviewed; and a technician opens the work order from the stop in the same system. Data is hosted in the AWS EU region, and Fabrico and the company behind it hold ISO/IEC 27001, ISO/IEC 20000-1 and ISO 9001.
Book a Fabrico demo
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Related tools: full troubleshooting directory · OEE calculator · downtime cost · MTBF / MTTR · glossary
Methods that cut recurring stops: the six big losses · root cause analysis · preventive vs predictive maintenance · TPM · SMED & changeover