Aeration ?

[boarderbloke]

Will aeration work in lowering grain moisture(wheat) from 15.5 to 14.5, when daytime lowest humidity is still 65%, and of course evening till mid morning is 93% or higher???

Will running fans 24hrs lower anything or will it actually go up?

Would running fans from 10am to 6pm be more helpful and take fewer days?

Haven't had any substantial rain here for two weeks and it's still foggy each morning with high humidties, even in the afternoon.

[farmaholic]

Find an equilibrium chart that will tell you if you'll make any progress at given temps and humidity. Some say run them continuously.... static pressure(air flow through the grain shouldn't be too high). Levelling the grain in the bin..... An agrologist once told me it takes alot to re wet the grain, but if the equilibrium moisture is higher than your target....why run the fans.. by the time the top is dry the bottom may be over dry, maybe better to aim for an averaged dry from the whole bin.....good luck.

[farmaholic]

Static pressure......air flow resistance......shouldn't be too high.

[Braveheart]

I always thought that when you get a drying front in your bin (when humidity is lower) you want to keep the fan running to keep that front moving up through the bin. Granted, some dampness will follow in these nights but, keep it going.

At the very least, you're cooling the grain which helps keep spoilage away.

[Hopperbin]

Mixed feelngs It often takes long time I thoughtbwhen running through the night when humidity high. Plus that deadly risk of fog. Bad shit. 50 times worse than rain in my opinion

[BreadWinner]

You can wire in a humidistat in you controls on a fan and have it turn on when under 60% humidity.

[TOM4CWB]

We find the most important storage conditioning key is lower grain tempature. If lowered from 30c to 15c the storage time without spoiling is 4 to 8 times longer.

Cool air hold much less water than hot air. Hence below 5-10c it is close to impossible to move moisture out of grain.

But if 10c air temp hits 30c grain... the air warms up... holds exponentially more moisture... so the grain cools and lowers in moisture... even though the RH at 10c was 80 or 90 percent.

Hence... 30c grain... cooled with air that averages 17c day and night together... will normally remove at least half a point of moisture just cooling grain down to 17c over a 3-4 day cool down period.

Just how it has worked in our aeration bins for 25 years.

Cheers

[TOM4CWB]

A temp sensor cable in the centre of the bin... from top to bottom will allow the operator to watch the temperature move through the bin.

The fan sucking and blowing out the roof... vents are best... will allow the top grain when cooled to be moisture tested... and give a reasonable idea what the bin average moisture will be.

[cottonpicken]

Anybody remember when we where talking about this a few years ago when that article came out about drying grain when the humidity was high at night or something like that?

[Braveheart]

Tom, that was one of the best explanations of natural air drying I've heard.

The natural air system can work well in spring as well. This past March we took 14.7% moisture wheat down to 13.9% in a few weeks. We were moving wheat into the US where the dry standard is 13.8%. We were surprised at how well it worked.

[TOM4CWB]

Braveheart,

We did exactly the same for wheat that was 16.5moisture and brought it down to 13 percent.

In the spring when the RH is low... bringing up the grain temp when low RH will reduce the moisture in Wheat nicely. May 15 to June 10 is usually quite dry air RH and worked well when we did it. Best are Full floor Air systems with 5hp on 5000 and 10 hp on 10,000 min with 18 foot eve max heights.

[farmaholic]

Tom, so once the grain temp has been lowered to average daily temps, we are back to relying on low RH and decent temps again?

And Cotton's point of only running the fans at night would have it's biggest effect only during Initial cooling, if cooler air holds
less moisture than warm air the same could be said for the grain? But once again, once its cooled to average daily temps, won't the RH have to be low and temps higher to get the grain to start drying
again?
I've always followed the equilibrium moisture charts. Your thoughts on moving the drying front and the chancesre-wetting the grain?

[boarderbloke]

Thanks for all the discussion and comments.

[TOM4CWB]

Farmaholic,

We have an old vertex 6600 grain dryer that if there is a big drying project... we will dry the wheat from 18 to 15 and not cool it... put it in an aeration bin and bring it down from 35c to 10c taking out the last point and a half of moisture in the cooling process... while increasing the capacity of the dryer by not needing to cool the grain in the bottom 2 tiers. Then we have blending power to go with Natural Air dryed grain... at say 16 percent moisture.

Objective being least handling of grain through the artificial drying system... most efficient least cost by blending to 14.5 on paper.

Have been able to work with our marketers and make this work.

All the best!

[Hopperbin]

Agree tom. Today in my area may not be able to dry only dry by cooling. Spring is a good time to aerate but must cool grain before winter. I just must comment anything under 3, 5hp fan through it away.