Hydrocooled apples stay crisp and tasty
The Gadbois family has planted most of its apples on Canada-developed Ottawa rootstocks. Trees at right are Sunrise on Ottawa 8; the smaller trees at left are Empire on Ottawa 3.
Photos by Richard Lehnert
incent Gadbois treats his apples as if they were vegetables or peaches or cherries. He hydrocools them immediately after harvest and puts them quickly into controlled atmosphere storage.
He built his own hydrocooler and a special airlocked transfer room so he can take apples in or out of CA storage as needed. He does not need to fill or empty an entire room at one time.
“Once apples are cold, the job is done and it’s easy to keep them cold,” he told visitors to Fruiteraie des Gadbois during the International Fruit Tree Association tour in July.
Vincent and his brother Benoit have about 50 acres of apples, with 15 varieties, and 100 acres of blueberries in the village of Rougemont, Quebec. Their father, Paul, started the business in 1979. They run a pick-your-own operation and also sell year round at a farmers’ market in Drummondville. Every Friday, ten family members and employees rise at 3 a.m. to serve the market, and over the year they’ll sell 2,500 bins of apples there, Vincent said.
In 2006, Vincent designed and built the hydrocooler and storage. He was the first in Quebec to hydrocool apples. He’s convinced that the people who buy his apples like them better and eat more of them because they stay crisp and tasty. “Sales follow the firmness of the apples,” he said.
It costs money to hydrocool. To keep equipment size and electricity consumption under control, he runs a 15-horsepower compressor all night to create a bank of 8 tons of ice and 7 tons of zero-degree water. “You can’t store cold air, but you can do an ice bank,” he said. With that, he is able to put 60 to 70 bins of apples into storage each day, dropping them from the field temperature of around 80 degrees down to 33 degrees in 25 minutes.
“There is no way to do it faster than this,” he said. “With air, it would take 25 hours to cool the apples. It works very, very well.”
The bins are kept clean. They are handled on a trailer and never touch the ground. The cooling water can be reused indefinitely with minimal filtration and treatment with ultraviolet light. “It is very important that the bins stay clean,” he said.
The bins go five at a time through a chamber in which 500 gallons of ice water per minute is pumped through the bins. The apples are not taken from the bins. Bins are moved into cold storage and then transferred into CA storage and kept at 2.5 percent oxygen.
Movement of apples is through a transfer room Vincent compares to an airlock on a submarine. The CA room can be entered with minimal change in storage conditions. Working in such a storage requires using oxygen tanks, Vincent said, as the storage is too low in oxygen to support human life.
He also developed a seal for the door to the cold storage that prevents air from seeping under the door. The bottom of the door sits in a track with an inch of water in it that forms an airtight seal.
The farm is unusual in one other way. When they switched to high-density plantings, they chose to use Ottawa rootstocks, developed in Canada, with a primary emphasis on cold hardiness. Ottawa 3 is the most dwarfing of the series, more dwarfing than M.26 but more vigorous than M.9.
The visitors saw an orchard of Empire apples planted in 1996 on Ottawa 3 and a 2006 planting of Sunrise on Ottawa 8, which is more vigorous than M.26 and rated as extremely cold hardy for planting in hardiness zones 1 and 2. Trees on Ottawa rootstocks require support, usually provided by individual tree stakes. •