Storing apples

This short essay touches on the steps that are within the reach of a competent home-orchard grower that will improve storage life.

Pick at the optimal stage of ripeness for STORAGE

They will be under-ripe for eating out-of-hand. Spraying cut apples with diluted tincture of iodine will give you a qualitative look at the ripeness of your apples. You need to test apples from several places in the tree's canopy to get a complete picture of what your crop is doing. Do NOT include apples with visible insect damage in your assessment.

Empire apple. Best time to pick for storage highlighted with red line. Source

Idared

Jonathan

The iodine stains the starch. When the flesh between the core and the skin of half of your samples start to show lightening, then the ripening process is irreversibly started and it is time to pick that variety of apples, speedy-quick.

One alternative to the iodine test is to cut at least four apples open and inspect the seeds. If most of the seeds are brown and a few are at least half-brown, it is time to get cracking and get the apples off of the trees. 

Cool the apples as quickly as possible

The old rule-of-thumb was that biological processes double with every 10 degrees F. Fruit left in the sun can hit 80F or 90F.

At one time it was a practice to soak freshly picked apples in a 1% calcium chloride/water solution to address water-core and bitter-pit issues and to cool them down. Soaking them for twenty minutes in two changes of very cold, well water is not a bad option. You can even add ice to the water if you can get it cheaply.

Sort-out damaged apples or process/can them

Damaged flesh generates ethylene. Ethylene catalyzes the ripening process which, in term, creates more ethylene. The ripening process accelerates from there. DO NOT STORE DAMAGED APPLES with the apples you intend to hold long-term.

Key point: The ripening process wants to accelerate. It is like a drunk dancing at the top of an icy sledding hill. Once it starts, there is no stopping it. The longer you can keep it near the start of the process, the longer they will keep. 

Dry the apples after soaking (if you opt to do that)

You don't have to go crazy over this but get as much of the water off of the exterior as you can.

Put the apples in relatively small containers

Five gallon nursery pots are a decent option. So are the wooden or cardboard trays that grapes are shipped in.

The goal is to promote ventilation so ethylene cannot concentrate locally and to promote drying of residual moisture. It also firewalls-off rot if it starts in one container.

Keep them cool

Remember: Every +10F halves the storage life.

Keep them ventilated

This sort of works at cross-purposes with keeping them cool.

Keep the storage area humid 

Self explanatory 

Final notes

Many of the best storage apples are almost inedible when picked at the proper stage for optimum storage life. GoldRush is a good example. It is acid, tannic and rock-hard.

Six weeks of storage mellows out the acidity, changes the starch to sugar and converts tannins into aromatic molecules.

The most common "mistake" in storing apples is to wait too long to pick them. That is, waiting until the fruit is prime for eating-out-of-hand is to wait much too long for picking storage apples.

So you are thinking..."What is the difference whether it is waiting on the tree or in my cellar?"

Fair question. On a sunny afternoon in late-September, that fruit can get up to 90F. If it is sitting in your cellar after you chilled everything down, it might be 60F or 65F. HUGE difference.