Storage: When to turn on the fan?

Aeration fans should be started as soon as the canola covers the floor of the bin, so that immediate cooling can take place. Fans must be operated continuously until the temperature of the canola is near the average outside temperature.

Operation of aeration equipment during extended periods of high relative humidity (over 80%) may promote mold growth, even in dry canola. However, continuous aeration through one or two days of high relative humidity will not damage the canola, as long as an equal time of dry weather follows. Since aeration is essentially a cooling procedure, the temperature of the air is more important than the relative humidity.

Tips:

–When the outside temperature has dropped below the temperature of the stored canola by 5 to 10°C, the canola should be cooled again.
–No conditioning operation is complete until the temperature and moisture level of the entire bulk have reached the desired level.
–After the bulk has reached the desired storage temperature, the bin should be checked periodically for evidence of heating or moisture migration.

Further reading:

Canola Encyclopedia section on storage
What to do with high-moisture canola?