What can malt barley producers on the Prairies learn about grain drying and storage from a country like Ireland, where the climate almost couldn’t be more different?
Quite a bit, says an expert familiar with both.
The weather is very different but Ireland and the Prairies share some similar challenges, notably dealing with high-moisture malt barley, said Drew Sharp, a Saskatoon-based regional agriculture manager with global malting giant Boortmart.
In a Top Notch Farming webinar earlier this year, Sharp outlined the barley-drying process used in a malt-processing plant in Athy, Ireland, saying it offered lessons for Canadian growers.
The facility buys almost all of its malt barley at harvest, and it typically comes off at 15 to 21.5 per cent moisture.
“They don’t get barley that’s really dry at harvest so they have to dry it down,” Sharp said during the webinar (put on by Sask Barley and the three Prairie canola commissions).
The Irish malthouse has a unique segregation system that serves as the basis for its drying system.
“They have a hydraulic probe measure every single lot for its moisture content. If it’s above or equal to 17.5 per cent moisture they’re going to bin that in one area and if it’s lower than 17.5 per cent they’re going to bin that in another.”
The separate bins indicate which barley gets a single drying treatment versus a graduated one. As recommended in Canada, all the barley is dried 72 hours after delivery at most.
So why not just dry all the grain down to 13.5 per cent — the typical contract spec for malt barley both in North America and Ireland — in the first place?
It comes down to germination. A rule of thumb in both countries says temperatures greater than 68 C should not be used to dry barley while the temperature of the grain should be under 42 C. These numbers help maintain the all-important germination in malt barley.
“In Ireland they find it’s difficult to remove more than four per cent moisture from the barley efficiently while adhering to (those temperatures),” said Sharp.
“They recommend drying barley with greater than 17.5 per cent moisture down to 16.5 per cent, cooling it for temporary storage and then drying down to 13.5 per cent within a few weeks once they have the time and space. In Canada, if you need to harvest wet grain, 17.5 per cent moisture might be a good threshold to avoid needing to dry twice.”
Don’t drown in averages
Boortmalt samples its malt barley extensively after drying, measuring moisture in smaller lots because averages can hide the fact that moisture content can be highly variable in the field, said Sharp.
“If you’ve ever taken a statistics class you may have heard about the danger of relying too much on averages,” said Sharp. “Someone tells you the average depth of this river is three feet deep. Do you cross it?… Because you can’t swim, maybe you shouldn’t because there are parts of that river that are 100 feet deep.”
It’s the same for grain moisture, he said.
“Although the moisture average might be 17.5 per cent there might be grain in there that’s 20 per cent and above.”
Most producers probably don’t have the capacity to test their barley to Boortmalt’s extent, but there are things they can do to help ensure uniformity. These include harvesting around immature patches and using higher seeding rates, which Sharp said usually provides better uniformity.
Moisture calls the shots
Aeration, which generally evens out temperature throughout the bin while cooling grain, is highly recommended. Boortmalt cools its barley using different metrics than most regions in North America, however.
“In Ireland the relative humidity is greater than 85 per cent most of the time, which means they have to be extremely careful when pressing air through the bulk whilst cooling,” said Sharp.
“This is because moisture can be removed from the air and deposited on the grain surface, activating fungal activity, heating and loss of germination.”
In order to prevent this, Boortmalt only aerates if the difference in temperature is 5 C or greater between the lowest grain temperature in the bulk and the ambient air being pressed through the grain.
“They want to make sure there’s at least a 5 C difference to make sure they are cooling in obviously high relative humidity conditions.”
While cold days post-harvest aren’t rare on the Prairies, it can be rainy and Sharp recommends not using aeration in high-moisture conditions because of the potential for infection by fungal organisms.
The sweet spot for medium- to short-term malt barley storage is 13.5 to 14 per cent moisture content at grain temperatures of 10 C to 14 C (300 to 190 days respectively). A consistent grain temperature of 6 C can theoretically keep the grain healthy for 1.3 years.
“Most of your contracts are going to be at 13.5 per cent grain moisture,” said Sharp. “So if you can keep your barley at 10 C and 14 to 13.5 per cent grain moisture, it should store for about 300 days.”