Stored Grain on Aeration: Turn Your Fans OFF In the Morning

Guess what? The old “turn the fans on and leave them on” at harvest isn’t necessarily true. Contrary to what farmers have been told and have been doing for quite some time, warm days actually add or maintain moisture levels in grain bins. Yes, really.

Research on the subject out of the Indian Head Agricultural Research Foundation was, at first, a head-scratcher for the researchers. Shouldn’t warm air with a decent relative humidity be taking water out of the grain and the bin and exhausting out the top? As it turns out, as the temperature difference between air temp and grain temp changes (as in, the grain cools), it actually makes the most sense to flip on the air at NIGHT only, as the outside temp falls.

In this video, Ron Palmer explains the research set up at Indian Head, the findings year over year and how and why this is the case. You don’t want to miss this.

If you cannot see the embedded video, click here.

5 thoughts on “Stored Grain on Aeration: Turn Your Fans OFF In the Morning

  1. Hi. I have been following Mr. Palmer via articles in Top Crop manager, The Furrow and Canola Digest. It’s too bad that this is a load of baloney on two counts:

    1)The only way cool air will increase it’s moisture holding capacity is by being warmed as Palmer stated. Once your grain is that cool night air temperature it will not dry one bit. Why not? Well, how can it? Do you seen dew on the grass in the morning? That’s because the air is saturated and cannot hold anymore and you think that air will continue ‘drying’ your bin? Not mine.

    In order for evaporation to occur heat is ‘used’. This is Jr. High physics. As you blow in that hot air it will cool in the bin as it is causing evaporation. Yes, it’s capacity to hold moisture goes down but your exit air will be of higher relative humidity than the air entering.

    2) Palmer’s own data shows that the system only runs during the day except for the last few days to rehydrate the bottom over dried grain. You can see the chart in Top Crop Manager – West: November 2012 – Page 34.

    We run our fans only during the day, not the night. That’s when our humidistat senses the air is try enough and turns them on.

    – Mark

  2. Dr. Palmer has lost his marbles. Using the night time only strategy minimizes the time in which you have to dry the grain, this increases the risk of not being able to adequately dry it to the desired moisture levels as well as potential spoilage. This is not an effective strategy at all and will leave you disappointed with the results 9 times out of 10..

  3. Leave the fans on all the time? Turn them on only during the day? Turn them on only at night? Everyone has lost their marbles? This is not rocket science so will there ever be a time of certainty when it comes to a simple thing like turning a fan on or off? Is there anything that everyone one will agree on??? How about this…a day like today, cold and windy, light rain coming down all day with light snow. Should you turn the fans off or leave them on?

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