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Bean lock might not happen with one origin, and start happening with a different origin. This is because density and size of the beans affects bean lock. The amount of chaff in the chaff collector also affects airflow: failure to empty the chaff collector between roasts may cause bean lock.
The different types of bean lock happen at different stages in the roast:
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Calibration: Ensure that your roaster fan speed is calibrated correctly. See Fan speed Bean circulation calibration.
Fan preview: Check circulation before starting a roast with Fan preview. If circulation is too low, correct it before starting the roast.
Reduce quantity of beans: If fan speed is correctly calibrated and beans are circulating correctly at the start of the roast, but you are still experiencing early or late bean lock, the simplest and quickest solution is to reduce the batch size. For example, if you have loaded 120g into the roaster and experience bean lock, try loading 100g or 80g until you are roasting successfully. If you have BOOST do this without changing the entered load setting.
Increase load setting: If you have BOOST, increase the entered batch size. For example, if you have loaded 120g into the roaster and experience early or late bean lock, try entering the load size as 140g or 160g. This will deliver more air to the same amount of beans.
Custom profile: If you are creating your own profile you should consider editing the fan speed profile to deliver more air in the parts of the roast where beans are locking up. See Uneven roasting for more help on editing the fan speed profile. If you are dealing with cooling bean lock deliver more air in the late part of the cooling cycle by increasing the ‘cooldown lo speed’ setting in the profile.
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