Freeze Drying Tips Roger Zauner 2023.09.30 Freeze drying food preservation is very similiar to warm rack food dehydrating preservation methods. Typically, from what I see, methods for blanching and cut sizes for typical food dehydrating should also be observed when using a freeze drying process. For example, although whole steaks and whole meat muscles can likely be freeze dried whole, although probably not a good idea for long term storage due possibly not being thoroughly dried! REASONS FOR OR NOT USING/PURCHASING A FREEZE DRYER Foods preferred for freeze drying are milk and egg dairy products. If a person has an abundance of these products, whereas canning, drying, salting are not acceptable methods; then this may condone purchasing a freeze dryer. Another plus, can maintain the quality and ingredients of foods being preserved. Keeping in mind, a freeze dryer is a heavy applience containing a heavy interior removeable aluminum rack, a rack much heavier and much more difficult than cleaning an aluminum pressure canner! Anybody older than fifty years old may consider, at most, only purchasing a small freeze dryer or continue using much cheaper and easy maintainable heating element food dehydrator and/or tried and true canners. To the point, the freeze dryers still require much physical energy maintaining (eg. obtaining and replacing parts yourself), the strong will for learning the lengthy freeze drying process and improvising when something unexpectidly breaks or happens. The process and equipment is still not a one-touch button process, and still far from it. However, with all the negativities stated within the document, Harvest Right seems to have a quality product, as the long as the consumer can tolerate and understand the laborous and mental requisites. Harvest Right User Manual, Owners-Manual-072020-DIGITAL.pdf (2020.07.20?) page 3, Safety Information: "This appliance is not intended for use by small children or infirm persons without capable, adult supervision. Children should be supervised when using the appliance." Noting infirm, not physically or mentally strong, especially through age or illness. Regardless, I've seen 70-80 year old people performing labor intensive tasks, or as long as an older person has a will or desire, they may make use of these larger freeze dryers with little difficulty. Once the unit is in place/installed, the rack is the most difficult item cleaning on/over a kitchen sink. Although it may seem reasonable for a rural person for needing a freeze dryer, whether for freeze drying wild game meat or for very long term food storage, the freeze drying process is quite lengthy for each item, requiring at least 24-48 hours for each item/load being freeze dried. So a trip to a rural accessible grocery store for purchasing all vegetables/fruits/meats at once, most of the food items will tend to rot or go bad waiting within the fridge to be processed within the freeze dryer. Some items, such as roast red bell peppers or tomatoes, will likely complete the freeze drying process far quicker than a common food dehydrator, due to the addition of vacuum subliming/extracting moisture from food. Whereas the common food dehydrator required 3-5 days or more, from memory. Also, electrical usage will significantly increase by 30% or even double with constant freeze dryer usage. Oil needs to be filtered/changed every other month. PLACEMENT OF FREEZE DRYER The freeze dryer units to be very large and very heavy. As to why people are placing the units high on table tops, becoming a tip hazard, shrugs. I decided to keep my medium unit on the floor with add-on rollers. VIOBEPASS Heavy Duty Furniture Movers with Lifter, ASIN B0BTSGZ9M2, $52.99 Sterilite 8 Qt. Dishpan Plastic White, 06568012, $1.98, Has 4.5 inch high sides. Heavy Duty 4x4 anti-vibration pads for increasing hieght of each roller/mover; two atop of each roller added the required additional height for draining into the 4.5 inch high dishpan tub. I also cut the translucent drain tube at 2.5 inches, providing clearance between drain water and the drain tube, should likely cut shorter. For leveling the unit, I use door composite shims. Using the shims also below the interior aluminum rack base, for leveling the rack especially when freeze drying liquids. I've seen many placing and installing the unit atop metal shelving without tip hazard prevention, or a strong strap bolted to the unit and wall stud, for preventing accidental tips. As of this date, after asking customer support, the units still apparently do not have a good tie down point for a anti-tip device or strap. CHECKING REMAINING MOISTURE For checking for any remaining moisture within food, I've found the "by touch" method for checking for cold or frozen interiors to be a haphazard method, or much like guess work. When long term storage is required, I've almost always added at least another 12-24 hours, if not ~48 hours. And for making absolutely certain all remaining moisture is removed, use a moisture meter with as small clearance of pins, such as the ERICKHILL Wood Moisture Meter, Model EWM01, $17.59. Also, within the settings, change the default one to two hours additional freeze dry time to ~12-24 hours. Typically your freeze dryer will auto complete the freeze dryer cycle using the internal humidity sensor for which never correctly senses remaining moisture here, with the process typically completing while you're asleep. From here, the unit adds ~2-4 hours additional dry time by default, and works if you're planning on being awake in a few hours. Instead I increase the additional dry time to ~12-24 hours, then I'm bound to be awake with the unit still actively freeze drying, without worry of food thawing or re-absorbing moisture. Additional time is a good thing for long term storage, as this ensures the food lacks any moisture. BEST STORAGE METHOD I've found the best storage method for most home users to be the typical canning jars with oxygen absorbers, subsequently vacuum sealing using appropriate jar adapters. Although sealing within the mylar bags is optimal, the only quality mylar bags today are the Harvest Right mylar bags. Matter of fact, I just started buying all mylar bags and oxygen absorbers directly from Harvest Right, rather than trusting any of the Amazon.com mylar and oxygen absorber products. The step-up in quality is quite noticeable with Harvest Right OEM products. Can check using a flashlight for holes within the mylar bag material. Using bags also incurs the problem of finding items on a shelf or plastic container. Best I've seen for shelving bags, are plastic organizer storage bins, with the best secure method for bags being plastic storage boxes with the offset of not being easily found. Again, I use the glass canning jars, with the benefits of being light weight and easily found when needed. Just make sure the glass canning jars, as usual, do not fall from the shelving. Typically, I either ensure I've cut/diced the food item into smaller dimensions for optimal storing in canning jars, or I use a food processor and easily powder the food item for canning jars. Once powdered, items can be safely stored in mylar bags. However, if the food items have sharp edges, can just put into mylar bags with adequate oxygen absorbers, omitting vacuum sealing. Some additional equipment: Food Handling Food Prep polyethylene gloves 1000 count $14.99 Silcone/plastic bowl/bench food scraper, for scraping food from metal trays LACK OF VACUUM SEAL DUE TO SEAL LEAKING Before each use, pull the large silicone seal from the seated position, forward from the unit, leaving about a width of a finger, or half to one inch clearance between the face of the unit and the seal. With vacuum, the seal will self seal. LACK OF VACUUM DUE TO SEAL LEAKING AND MOISTURE FREEZING AROUND SEAL. Using a heat gun on low setting, or a hair blow dryer, gently thaw the large silicone seal while the unit is within the food check for dryness stage. I've found the inner seal not frozen to the metal casing, while only the exterior was frozen to the metal. Use the the low heating tool around the exterior of the seal until the seal is free, reset the seal and restart the freeze drying process. This is work in progress, and only recently the other day had to resort to this heating trick for continuing multiple subsequent failed freeze drying cycles. (Just notified Harvest Right today, seems I may have a bad seal, since delivery, been seeing cracks within the inner slit of the seal. The unit only has 1000 hours or ~3-4 months use. 2023.10.02) PREMIER VACUUM PUMP OIL CHANGE The premier vacuum pump seems to require an oil change whenever the oil is significantly cloudy. My first change was at 1,000 hours, found the oil was very dark yellow, however the glass view port displayed crystal clear oil. Can estimate the number of hours with each batch being 24-48 hours in length, and 20-30 batches being the manual's time span. (eg. low-end 24 * 20 = 480 hours, upper-end 48 * 30 = 1440 hours) As far as filtering, the manual states filtering should also be performed at the same time span. So I'm guessing, the reason for required oil changes are only due significantly lack of transparency with the oil. I found no water with my initial oil usage either. FOOD/LIQUID EXPLOSIONS If I'm not mistaken, reason for so-called food explosions within freeze dryers, the liquid and/or food is not completely frozen prior to application of vacuum. Food item then subsequently rapidly heats, far more then usual. For preventing, increase the freeze time within the settings from one to two hours. I have yet to have any subsequent explosions with milk/liquid items. VACUUM SEALING CANNING JARS It has been stated on forums, ~15 PSI (75 torr, 75,000 mtorr) is adequate for vacuum sealing canning jars. Sealing canning jars within the freeze dryers typically using only vacuum is typically for about a minute (19,200 mtorr), far exceeding 75,000 mtorr. Remember, use a canning ring and only very slightly tighten the ring, else the lid alone will not contain a vacuum within the jar. SCRAMBLED EGGS WITHOUT PRE-COOKING For making scrambled eggs without pre-cooking the eggs before freeze drying, change the dry temperature to 145F within the freeze dryer settings. Using a salmonella kill time/temp ratio chart, all salmonella is likely already killed at the default lower temperature by the long term 24-48 hour freeze drying process and vacuum subliming increasing temperature. Using 145F temperature, will adequately cook the eggs, but may still can reduce to 140F as I sense the end result eggs still having a slight rubbery texture. Mountain House Scrambled Eggs adds potato/tapioca starch, and the lighter fluffier eggs likely has at least 1 tablespoon of water to each egg, and very likely the whites are initially separated and beaten until stiff peaks, then yolks likely re-incorporated. Starch is likely for palate texture or preserving the stiff peaks texture. As to why people are pre-cooking their scrambled eggs prior to freeze drying, shrugs. To prepare or rehydrate, simply add boiling water, stir, cover and let sit for ten to fifteen minutes, the stir once again. Already tried the end result twice, once at a hotel, and seems to work fine. Instant potatoes work well along side the freeze dried eggs, as long as there's access to water, preferabley heated/boiling water. SILICONE MATS FOR TRAYS This is about the only other accessory I have purchased. The silicone mats are desireable when freeze drying liquids, such as milk, eggs, mashed potatoes, etc. Typically cut vegetables do not require mats, as the freeze drying process prevents most sticking to the metal trays. I've yet the need for dividers, as I either use canning jars and/or food processor into powder. ENERGY USAGE First 3-4 months electrical usage is a significant 30% increase, or sometimes doubled my electric bill. (eg. $150 monthly electric bill will likely increase to $200-225 monthly electric bill.) Think about it. The unit contains a vacuum pump, freezer/compressor (pump) and at least four heating matts; with energy usage likely in order. From my experience, pumps tend to require higher amount of electricity in comparison to low-level heating elements.