Using it all: Drying Apples
The Penn State Extension Energy, Business and Community Vitality team has identified having "excess fruit and vegetables" (beyond direct sales and wholesale) as a significant challenge for specialty crop producers. Adding value by drying excess produce results in extended shelf life and an alternative consumer offering.
In this video, co-authors McGee and Sivanandan discuss why farmers might consider adding value to their surplus, then cover the steps of preparing, producing and packaging to convert fresh apples to dried slices.
- [Winifred] In today's economy, many farmers are looking for ways to increase farm revenues beyond just selling directly to the consumer.
Adding value by drying will allow you to create a consumer-ready product that will have a shelf life of up to a year after processing.
This video shows the simple steps needed to dry surplus apples, taken from the research of co-author, Dr. Litha Sivanandan, Extension Specialist and Associate Professor for Food Safety and Food Preservation, for the West Virginia University Extension Service.
Dr. Sivanandan has experience with commercial and university research that is valuable for producers who want to add value to their excess produce.
Not all fruit that is produced looks this pretty, and even if it is perfect and produced in the safest manner possible, that's no assurance that it will sell.
One way to recoup the investment of complying with food safety programs like good agricultural practices, good handling practices is to use all of the crop that you produce, even the ugly fruit that doesn't sell at the farmer's market.
However, there are a number of steps following the processes of preparing, producing and packaging, that you'll need to know to create great dried apples.
Let's start with preparation, where apples in their natural state are made ready for the drying process.
It all starts on your farm with harvesting, drying and arranging for transportation of your apples to a commercial or shared kitchen where the equipment is available to have your apples prepared, dried and packaged.
You'll want to outline a schedule so that these tasks run smoothly.
Once transport is complete and you have the apples at the commercial kitchen, you'll need to divide them into batches that will fit your work time schedule and the available dryer space.
Organizing the fruit will keep you from delays midstream that may result in waste or subpar product.
An important part of using a commercial kitchen is making sure of sanitation.
Change out of your street clothes and put on an apron to avoid contaminating the product.
Wash your hands well, rinsing hands in warm water, applying soap, scrubbing for 10 to 15 seconds, rinsing with warm water again and drying with a paper towel.
Prepare you work surface by scraping any food residue, if necessary, washing it with soapy water, rinsing with warm water, and then sanitizing and letting it air dry.
You'll also want to prepare your cutting board and any other implements by washing, rinsing and sanitizing.
Finally, wash your hands again and put on gloves to prevent direct hand contact with the food.
Already having selected apples for your batch, you'll need to peel the apples, unless your product will benefit from a bit of peel on the edge of the slices.
For some products, coring will be done at this point in the preparation.
After your apples are peeled and cored, slice them thinly enough to make drying successful.
Depending on the product you want to make, you can either choose rings or chip-type slices.
Having completed the basic preparation steps, it's now time to move on to production.
Many people prefer a dried apple that still flexes.
It's chewy but not crunchy.
This is achieved through osmotic dehydration of your apples.
Pre-treating your fruit in a sugar solution before it is put in the dryer binds some of the water so it'll remain but not be active in the finished product.
This provides additional food safety and improved flavor and texture.
The process is as follows.
There are several concentrations for sugar solutions, 45 degrees, 55 degrees or 65 degrees Brix.
Degrees Brix is the proportion of sugar by weight to water by weight.
So, in a 55 degrees Brix solution of 1,000 grams, you'd have 550 grams of sugar to 450 grams of water.
Research has shown that 55 degrees seems to yield higher quality apples.
Having chosen the desired concentration, determine the amount of solution needed for the quantity of prepared apples.
It is a one to three ratio, apples to solution.
If 500 grams of apples have been prepared, 1500 grams of 55 degrees Brix solution will be needed.
You see the computation on the screen, 55 degrees Brix sugar solution uses 825 grams of sugar.
Subtracting that 825 from the total of 1500 grams of solution, 675 grams of water are needed.
Measure and mix the sugar and water in a pan, dissolving all the sugar so that the liquid is fairly clear.
Heat it slowly on the stove top to dissolve all the sugar.
Place the sliced apples into the sugar solution.
Leave them in this solution for four and a half hours, stirring them occasionally.
The osmotic dehydration will work better if you keep the temperature at 100 to 120 degrees Fahrenheit.
To do this, you will either have to keep the pan on the stove top and test the temperature regularly, or you may place the covered apples and solution in a pan in the oven set to warm, 130 to 140 degrees Fahrenheit.
At the end of the osmosis process, remove the apples from the sugar solution and rinse lightly with cold water.
Place the apples on the rack to be put into a conventional dryer.
Place your racks of apples in the dehydrator and set to the temperature appropriate for apples suggested by the manufacturer.
This varies from 165 to 200 degrees Fahrenheit.
In this picture, we see that strawberries and fruit leather are being dried at the same time as the apples.
Notice how the fruit leather is on a special sheet so it will catch the drips from the strawberries above, but the red juice will not drip on the apples below.
If you're using a shared commercial kitchen and others are using the dehydrator the same time you are, careful thought needs to be taken about the order of the trays.
Rearranging the order of the trays and turning the fruit is recommended for faster drying time and even drying of the product.
This will also avoid darkening of the apple's color on one side and provide even shade of the final product, therefore, overall appearance or quality of the product will be better too if you systematically work with the trays.
For your apples, the total drying time will depend on how thick the apple slices are and the drying temperature you select, but it will usually be about three and half to four and a half hours.
Because you're drying apples for commercial use, you'll want to verify that the fruit is dried sufficiently.
Using a water activity meter and a moisture gauge, take a few sample apples from different sections of the tray to use for testing.
By using this process, you will ensure that any water has either been bound by osmosis and therefore is not active, or has been removed by the drying process so that your product will be safe and will not produce mold.
A safe water activity range for apples treated with 55 degrees Brix sugar solution for four and half hours at 120 degrees Fahrenheit is 0.50 or below and a safe moisture content will be 12% wet weight.
If your sample shows that there is still water activity, you may have to return the tray to the dryer for additional time, spot checking regularly.
If you've reached the desired water activity range and moisture content, you're ready to move to the final phase, packaging.
As you can see in this picture, when production is completed the work is not quite done.
The object is to package the product into clean, dry, insect-proof containers as soon as possible and as tightly as possible without crushing.
Dried fruit is susceptible to insect contamination and moisture reabsorption.
Once the apples leave the dryer, cool them completely at room temperature.
When the product is cooled, it needs to be conditioned before final packaging.
Fruit fresh from the dehydrator may have remaining moisture that is not distributed equally because of the size of the pieces and their location in the dryer.
Conditioning is accomplished by placing dried product in jars, sealing the jars, and letting it sit for seven to 10 days, allowing some of the drier pieces to absorb the sweat from moister pieces, equalizing the moisture and reducing the risk of mold growth.
Conditioned fruit can then be packaged.
Many producers select a high-grade plastic bag like the one that's pictured.
Notice that the bag has a zipper seal and then is heat sealed.
The original air is allowed to remain to cushion the product and prevent crushing, but no new air with additional moisture can get in.
Once you have your apples packaged, they can be stored in a cool, dry, dark area from four months to a year.
It's not necessary to refrigerate, but the higher temperature in your storage area, the shorter the storage time.
Most dried fruit can be stored for one year at 60 degrees Fahrenheit or six months at 80 degrees Fahrenheit.
This video has demonstrated one way to invest time and energy, creating a delicious, nutritious snack for your customers.
At the same time, you have remade your surplus fruit, extending shelf life and using it all to recoup costs of farm production.
It will take some time and practice to perfect your product, but expanding your market in this way reduces financial and marketing risks and differentiates your business from your competitors.
We thank USDA for funding that has helped to support development of this program, addressing financial risk management through drying excess specialty crops.
The information that you have just viewed is part of the Penn State Extension led project, Reducing Marketing, Legal and Production Risk for Specialty Crop Producers by Adding Value.
If you're interested in broadening your agricultural venture by adding value to excess product, please contact me, Winifred McGee.
Technical aspects of drying apples are based on research conducted at West Virginia University.
If you have specific questions about how you might start drying fruit or vegetables, please feel free to contact the co-author of this video, Dr. Litha Sivanandan.
She will be more than happy to work with you.