Fall is harvest season and here in Oregon, farm workers are busy plucking apples, pears, hazelnuts, wine grapes, and prunes. Note that I said prunes, not plums. Prunes (fresh or dried) come from several cultivars of freestone plums that are meatier, with less water than a typical plum.
It can be said that all prunes are plums but not all plums are prunes. This truth is muddied a bit by marketing, because starting in 2001 the FDA allowed prunes to be called ‘dried plums’.
I was fortunate to take a tour of the Elliott Farms prune orchard during harvest last month. The farm, started in 1882, is the largest in the Willamette Valley, encompassing 55,000 trees over 700 acres. Bruce Elliott is the fourth generation to oversee the land and has a very hands-on approach. During our visit, Bruce was busy wheeling racks of prunes into one of the dryers. But I’m getting ahead of myself.
Let’s start with the ripe, deep blue, elongated fruit hanging on the tree in the warm sunshine. The prune harvest season starts with Bruce and his team carefully assessing the fruit on the trees. This is delicate dance between a high enough Brix (sugar content), typically 20-24, and time. The longer the fruit is on the tree the higher the Brix. But the higher Brix means the fruit is softer which increases the chance of damage to the skin and the skin is crucial.
The tree-shaking method of harvest actually helps in this situation. A shaker enfolds the tree trunk and gently shimmies the tree for about ten seconds. Ripe fruit falls onto the tarp-like material before rolling down to the conveyor belt of the receiver tractor. Fruit that needs more ripening time remains on the tree until the next pass of the machinery in a couple weeks.
Now the real race against time begins. The fruit is hauled back from the orchard for processing. After a quick shower, prunes are sorted and placed on drying trays. The sorting crew removes any leaves or stems while small fruit falls through the mesh (this pile later returns to the orchard as mulch).
Each 3’x3′ drying tray has a single layer of prunes. Trays are stacked on a wheeled rack two dozen high. Every two hours one of the large drying tunnels is opened and twelve racks of fresh fruit are wheeled in one end, pushing twelve racks of dried fruit out the other end of the tunnel. The drying tunnels are heated to 180 degrees forcing the prunes to release roughly 100,000 gallons of water a day.
The freshly dried prunes are dumped out of their trays into holding bins to continue sweating. The prunes must be dried within 24 hours of harvest or ‘box rot’ can set in and ruin the fruit. Elliott Farms has four of the dryers so it was a whirlwind of constant motion. Watching the crew was mesmerizing. Even though they only did this for six weeks of the year, they were a well-honed system.
While prunes are much-maligned here in the States, they are a desired commodity in Europe and China. Though the overall harvest for 2018 was reported down about 25% because of water-stress, it should still be a profitable crop. In 2017, prunes fetched $1970 per dried ton (or $635 per wet ton). Oregon is a distant second to California in prune production: with over 1300-acres planted, yielding 4220 tons (according to the 2015 USDA Noncitrus Fruits and Nuts report).
Not only did I enjoy my educational tour but we were allowed to sample both fresh and dried prunes. I loved the fresh fruit, it was meaty and flavorful but much easier to eat than a plum. Let me tell you, if you’ve only had them dried you are missing out!