Unless your trees have produced very little fruit you will have more than you can sensibly eat immediately, so you need to find a way to preserve or store them. How to store apples is a question that comes up regularly so perhaps it is time to look at the subject in more detail.
Before we get down to details, it is worth just looking at the biology of apples which will help to explain the rationale for storage methods. Apples are climacteric fruit – which simply means that they continue to ripen after harvest. However they will only continue to ripen if the ripening process had already been triggered before they were picked. The exact trigger for ripening fruit is still being investigated by plant scientists but we know that there appears to be a gene related ‘switch’ that triggers the release of the plant hormone ethylene which causes the fruit to ripen. The ripening process sees starches in the fruit flesh converted to sugars and changes in the acid content. All of this is to make the fruit more attractive to animals who will then consume it and spread the seeds.
So what does this mean for us when we want to store the fruit? It may be tempting to think that perhaps we could harvest the fruit early then let it ripen more slowly in storage. The danger with this is picking it before the ripening process is fully underway which means that the fruit will never ripen properly and so remain hard and tasteless. Commercial growers have very clever ways to gauge the point when ripening is just sufficiently advanced that the fruit can be picked and quickly put into controlled atmosphere storage but this is not an option for home growers.
However, storing apples at home is fairly straightforward, even without the clever technology of commercial growers, and can be successful by following a few simple rules.
The first, and most important, rule is to choose your fruit with care, it is simply not possible to store some varieties of apples for any length of time. As a general rule of thumb, the earlier the apple ripens the shorter storage time it will have. An example is Beauty of Bath, which ripens in early August, is delicious straight from the tree, but within days it is past its best. Apples such as Discovery and Epicure which ripen late August/early September are past their best after a few weeks. However, most of the apple varieties that ripen from October onwards will store for at least a few months. My personal favourite for a dessert apple that stores well is Fiesta. It will usually keep in good condition through till April but this year, as I was cleaning down the storage racks at the end of August ready for the new season, I discovered two Fiesta apples lurking at the back of the rack. They were beginning to show their age but still perfectly edible more than 10 months after they were picked!
Once you have your late ripening apples, check them over for any damage. Any apple which has signs of insect damage or bruising will very quickly rot so need to be used up fairly quickly. They can often be stored for a few weeks but it is better to keep them separated from sound fruit. The ethylene released in large quantities by fruit as it decays will hasten the ripening, and deterioration, of nearby fruit.
Apples for longer term storage should be clean, dry and in good condition.
The next thing to consider is how to store the fruit. All biological processes are temperature sensitive so cooler temperatures will slow down the ripening and ageing process. The level of moisture will also affect storage, too much moisture will encourage rot but a very dry atmosphere will increase the rate of water loss from the fruit during respiration. A dry (no leaky roof), frost free garage or outbuilding is ideal. I am told that years ago the apple crop could be stored under the bed in the attic bedroom but that was in the days before central heating. Another common practice from years gone by is wrapping the apples individually in newspaper both to stop moisture loss and stop the fruit from touching. The problem with this method is that you have no idea what is happening inside the wrapping so have to either keep opening them up to check all is well or wait until you notice the soggy mess of rotting fruit seeping through. It is a good idea to prevent the fruit from touching but a simple way of doing this is to collect the empty fruit boxes from shops and supermarkets.
These have fruit sized depressions in the cardboard trays so all your fruit is held in place and can be inspected quite easily. The boxes can simply be stacked together and there will still be some space for air to circulate.
If you are going to be storing larger quantities of fruit it might be worth investing in purpose built wooden storage racks. These are very convenient, will last a lifetime and they allow some air circulation through the slatted bases and sides. If you place the fruit with the stalk hanging down through the slats it will help to stop them rolling together when the individual trays are pulled out for inspection.
The final thing to consider is rodents. Mice and voles will find your stored apples irresistible and take a little nibble from each fruit so it is worth taking precautions to keep them out. These creatures can squeeze through tiny gaps so a bit of ingenuity is called for if you want to deter them. Sadly we don’t have a foolproof answer for that one!
The Northern Fruit Group 