Regardless of how great red lentils look going into the bin, moisture migration problems will show up during processing and cooking. What’s more, the variety you grow may stack the deck against you.
Stefan Cenkowski, a professor with the University of Manitoba’s biosystems engineering department, presented his findings on post-harvest quality management of red lentils at Saskatchewan Pulse Growers’ annual meeting in Saskatoon in January.
Cenkowski and colleagues looked at what effects variety, storage conditions and time in storage had on ease of de-hulling and cooking quality of red lentils. Cenkowski included Impact, Robin and Red Berry in this trial.
Whether lentils went in the bin at 10 or 13 per cent moisture made little difference, Cenkowski says. Making the greatest impact, both off the combine and after 12 months in storage, were first, variety, and next, moisture fluctuations within the bin.
Red lentils need intermittent ventilation, to ensure wet spots are taken care of right away, he said, and to avoid moisture migrating through the bin.
Actual seed moisture mattered very little to the eventual processing quality, Cenkowski adds. “It’s the re-wetting that happens in the bin that cause the seed coats to swell and then dry. That causes wrinkling,” he says.
That wrinkling not only looks bad, but it also manages to cause a big problem when it’s time to de-hull the lentils — a must for the red lentil market.
Perhaps more surprising than the importance of dry bins is the impact variety choice has on the outcome of processing and cooking quality. In all cases, the No. 1 factor on quality maintenance — variety choice — isn’t something you can change post-harvest at all.
Of the three lentil varieties tested, Cenkowski’s research suggests Impact fared the worst in de-hulling and cooking characteristics after facing the stresses of storage, and even immediately post-harvest.
The results of Robin and Red Berry were more mixed, though Red Berry seemed to de-hull easiest and maintain its cooking quality in spite of storage stresses.
Beyond lentil variety choice and intermittent ventilation, your best chance of maintaining red lentil processing and cooking quality is to store only clean seed, Cenkowski says, as dockage will dry at a different rate and could cause wet patches within the bin.
Lyndsey Smith is a field editor with Grainews
in Lumsden, Sask. Email her at [email protected]