Hydrocooling
Hydrocooling, quite simply, is cooling by water (hydro – Greek for water). Hydrocooling sweet corn is the process of removing field heat from corn by immersing it in ice cold water as soon as it is picked. This slows the heat of respiration process which uses the sugar in corn as its energy source. When the cob is harvested from the stalk, heat of respiration begins and it uses the sugar in the kernels as fuel for this chemical reaction. If not cooled immediately after picking, corn can lose over 50% of its sugar in just 24 hours as shown on this graph.
At Hunter Brothers, after our sweet corn is hand-picked and hand-graded, it is cooled in a cedar-shaded, spring-fed pond for 6 to 8 hours. The corn floats and therefore must be turned halfway through the hydrocooling process to ensure that all the corn get cooled.
Loss of sugar during storage at four different temperatures. (Source: USDA handbook No. 66: The Commercial Storage of Fruits, Vegetables, and Nursery Stocks.)
After being removed from the pond it is either put into the walk-in cooler in our market or stored on the back of our delivery truck with a sprinkler applying cold well water continuously.
When you hold our hydrocooled corn in your hands, you can feel that it is cool and wet. Corn that has not been cooled after picking will feel warm and dry. This is a sign that it has likely lost a substantial amount of its sweetness.