1Drying Foods Jananne Finck, MS, RD. Nutrition & Wellness Educator Springfield Center
2Drying is New Again One of the oldest methods of preserving food Alternative to canning & freezingSimple, safe and easy to learnCan dry year roundNo refrigeration neededTakes little space
3How Drying PreservesRemoves moisture from food so bacteria, yeasts & molds can’t grow and spoil foodSlows down action of enzymes but doesn’t inactivate them
4Temperatures for Drying Optimum temperature for drying food is 140°FIf higher temps are used, food cooks instead of dryingAvoid “case hardening” – dried outside and moisture is trapped inside – mold results
5Helps Drying… Low humidity aids drying Increasing air current speeds up drying, removes air around food
6Ways To Dry FoodFoods can be dried in the sun, but often doesn’t work well in Illinois…need several days of high temp and low humidityDry in an ovenDry in food dehydrator
7Drying Out-Of-Doors Sun Drying Dry fruits, high sugar & acid make them safeDon’t dry vegetables or jerky/meat outdoorsNeed hot, dry, breezy daysTemp of 85ºF. or higher, for several days with humidity below 60%Need to cover, watch materials used and control for insects and pests
8Out-Of-Doors Solar Drying Vine Drying Need to make a dryer Need to stir and turn food several times a dayNeed several days…Vine DryingDry beans, lentils and soybeansLeave bean pods on vine until beans inside rattleIf not dried can dry further in oven or dehydrator
9PasteurizationFreezer Method – seal food in freezer plastic bags. Freeze at 0ºF for at least 48 hoursOven Method – Place food in single layer on fray or in shallow pan. Place in oven preheated to 160ºF for 30 minutes
11Food Dehydrators Small electrical appliance for drying foods indoors Electric element for heat & fat and vents for air circulationDry foods fast at 140ºFBuy at department stores, mail-order, garden supply, internet
12Costs?Costs vary depending on features. Some are expandable & extra trays can be purchased. Twelve square feet of drying space dries about a half-bushel of produce.Major disadvantage of dehydrator is limited capacity.
13Dehydrator FeaturesDouble wall construction of metal or high grade plastic, not woodEnclosed heating elementCounter top designEnclosed thermostat from 85ºF-160ºFFan or blower4-10 open mesh trays, plastic, sturdy, washableUL seal1 year guaranteeConvenient serviceDial for regulating tempA timer, auto- shut off
14Types of Dehydrators Horizontal Air Flow – Heating element and fan are located on sideMajor advantages – reduces flavor mixing so different foods can be dried at once, all trays get equal heat, juices don’t drip into heating elementVertical Air Flow –Heating element and fan located at baseMajor disadvantage –if different foods dried, flavors can mix and liquids can drip into heating element
15Oven DryingSlower than dehydrators, unless you have a convection oven, which has a fanTake 2 times longer to dry in oven than dehydrator…oven not as efficient and uses more energy
16Using Your Oven Dial needs to go down to 140ºF Leave oven door propped oven 2-6 inchesBest if you place a fan outside oven doorOven temp varies…so need accurate oven thermometer to be sure 140 is achievedTrays should clear sides of oven & 3-4” shorter front to back of oven, 2-3” between racks in oven
17Room DryingHerbs, hot peppers, & nuts in shell are most common air dried foodsHerbs & peppers – strung on string or tied in bundles and suspended from overhead racks in air until dry.Can enclose in paper bags, with openings for air circulationSpread nuts in single layer on paper
18Drying Fruit Preparing the Fruit – wash fruit and core, if needed Fruits can be halved or sliced and some left wholeThin, uniform, peeled slices dry fastestApples can be cored and sliced - wedges, ringsBananas can be slicedIf fruit dried whole, “check” or crack the skin to speed drying – cranberries – place in boiling then cold water to “check”
19Pretreating the Fruit Sulfuring Sulfite Dip Ascorbic Acid Ascorbic Acid MixturesFruit Juice DipHoney DipSyrup BlanchingSteam Blanching
20Drying the Fruit Place fruit in single layer Follow directions given Follow approximate drying times givenWatch food as it dries much faster at the end of drying period
21Determining Dryness of Fruit Most fruit – should have 20% moisture content when driedCut several cooled pieces in half…should be no visible moisture and should not be able to squeeze any moisture from fruitNot be sticky or tackyIf piece folded in half, shouldn’t stick to itself
22After Drying…Cool fruit minutes before packaging…don’t pack too soon or moisture buildup could occur…don’t wait too long or could pick up moisture
23Conditioning Fruits Conditioning equalizes the moisture. Pack cooled fruit in plastic or glass jars, seal and let stand for 7-10 daysShake jars daily to separate pieces and check for moisture condensationIf condensation, return to dehydrator for more drying…unless has started to mold, then dispose of
24Drying Vegetables Preparing the vegetables Wash, trim, peel, according to directionsUniform piecesDry as soon as possible after picking
25Pretreating Vegetables Water blanching – follow times given, start counting time as soon as water returns to boil. If takes more than 1 minute to return to boil, are putting in too many vegetables at a timeSteam blanching – Vegetables should be no more than 2 inches deep above boiling water. Cover and steam according to directions given for each vegetable
26Cooling VegetablesDip briefly in cold water only long enough to stop cookingCool to they feel only slightly hot to touch…about 120ºFWipe vegetables and place in dehydrator
27Determining Dryness of Veggies Dry vegetables until brittle or “crisp”Some vegetables shatter if hit with hammer10% moistureDon’t need conditioning like fruits, as lower moisture content
28Fruit LeathersFresh FruitCanned or Frozen Fruits
29Drying Fruit Leathers Pour 1/8-inch thick on drying tray Take 6-8 hours to dry in dehydrator, up to 18 in ovenDry at 140ºFDry when no indention in center of leatherWhen warm, peel from plastic and roll , cool and rewrap roll in plasticKeep up to 1 month at room temp, then may freeze up to 1 year
30Jerky Lean meat like beef, pork, venison or smoked turkey breast If wild game is used, treat to kill Trichinella parasite by freezing a portion 6 inches or less thick at 0ºF at least 30 days…this doesn’t kill bacteria though
31Eliminating E. coli O157:H7 Risk Heating dried jerky strips in oven after drying process is completed. Heat strips 10 minutes in oven preheated to 275ºF. Thicker strips may take longer heating, check temp (160ºF) with thermometer.Heating meat strips in marinade before drying – drying times will be reduced. Check temp of several strips with metal stem-type thermometer to determine 160ºF is reached.
32Storing JerkyProperly dried jerky keeps at room temp for 2 weeks in sealed container.For best results, to increase shelf life and maintain best flavor and quality, refrigerate or freeze jerky.
33Reference “So Easy To Preserve” Cooperative Extension Service The University of Georgia, 4th Edition, 1999.