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Freeze Drying Off Grid
Embracing the Limits of Our Solar System
When I first learned about freeze dryers, I wasn’t really interested. I can a lot of food already, from fruits and vegetables to meats, the old fashioned way. Even my water-bath canner comes in a close second to my old school pressure cooker. And don’t even get me started talking about “Rebel canning…” To me, The Ball Blue Book is sacrosanct.
Then again, I’ve been wrong before…
I first ran into these freeze dryers at North 40 and then, days later, at our local True Value Hardware… they seemed to be everywhere all at once, working to wear down my resistance.
Not that I’ve done a lot of investigation on the matter, but it seems that Harvest Right brand freeze dryers are just about the only household option out there (let me know if I’m wrong). They come in four sizes and prices range from $2,200 for a small to $5,000 for an extra-large.
After doing some research, I started to lean toward making the investment on a medium-sized unit. Harvest Right, along with a host of YouTubers, all made claims that food processed in the freeze dryer was superior to dehydration and canning. The visual evidence was overwhelming: a strawberry still looked like a strawberry; an avocado was still green…you get the idea. Perhaps most importantly, they claim freeze dried foods can remain preserved anywhere from 10-20 YEARS!
What really sold me was the ability to freeze dry foods that can be used in the event of emergency to create actual meals…. like powdered eggs for baking, powdered cream or, my favorite, cheese! The prospect of freeze drying vegetables and fruits from the garden was also a plus, as these can get kind of mushy via canning.
As we discussed buying one, John had valid concerns about the power usage. Could our system handle it? We searched online for charts that might track the machine’s energy usage throughout the process, but found very little specific information. Finally, we decided we’d try. We’d buy one, save the receipt, and hope for the best.
That was in May.
Meet Lil’ Chuckwagon…
After several successful batches, I’m pleased to report that our solar system handles the freeze dryer just fine. That said, there are some unique considerations and adjustments we make before using it. We’re going to share those here, as well as some very specific information regarding the power cycles the unit goes through during processing. Hopefully, this information will be useful if you’re off grid and considering whether a freeze dryer is right for you.
First of all, we start batches very early: 6AM. I get everything ready the night before so when the alarm goes off, I can get right to loading the machine.
This is our “alarm”… did you know German Shepherds sleep upside down? Odd but true…
I load the machine first thing to take advantage of maximum daylight hours. Freeze drying cycles can take anywhere from 10-48 hours, depending on the food type. Also, most days here are sunny, but if it’s going to be cloudy or rain I’d probably skip it altogether and try another day. It’s not that we can’t freeze dry any day of the week, regardless of weather or time, it’s just not as efficient to run the generator (which uses propane) as it is to utilize the sun. So, timing is important.
We also have to think about what other draws might be tasking our power system. For instance, the well pump is set to come on automatically when the cisterns drop below a certain level. Once, we had spent the previous day (6AM until 2AM) with the freeze dryer running (which uses battery reserves at night). Later that morning, the well pump automatically came on when it was triggered by the cistern float. Because our battery reserve had been drained by the freeze dryer much of the night, the well pump caused the generator to switch on.
While the generator coming on wasn’t a problem, it was a reminder to be aware of drawing power from a battery bank that might already be low. Typically, we don’t have anything running at night, so the freeze dryer creates a special circumstance.
As a result, we now have a post-it stuck to the door of Lil’ Chuckwagon. It simply says, “Well Pump” as a reminder to flip the well switch off before I start drying.
I should also mention communication here, so that everyone in the household knows and plans around the dryer’s power draw.
So far, we’ve processed various batches of ground beef and beef meatballs; strawberries, blueberries, raspberries, and avocado; shredded cheeses; eggs to make egg powder; chocolate chip cookies; and fresh herbs (basil, cilantro, oregano, and thyme).
Some foods reconstitute more easily and successfully than others. I don’t recommend drying avocado unless you like eating avocado chips (some people do), and basil is much better fresh, although the other herbs did great. Blueberries tend to “burst” a bit, but every other fruit preserved perfectly.
Regarding shredded cheese, the finer the shred, the better.
Ground beef is the only meat I’ve processed so far, and it’s been a winner. That said, I actually still prefer canned meats to dehydrated or freeze dried meats. If you plan to add them to a stew, for instance, dried meats are fine, but canned meats (IMO) just taste better and are more tender.
Like any long-term investment, though, it’s always smart to diversify your food preservation methods.
We tracked the power load of the unit during several full processes. We used a Reliance Appliance Load Tester to track the unit’s power draw throughout each cycle. The tester doesn’t record; it’s immediate read/use so our records are approximate (meaning we weren’t watching the meter every second). We found that the freeze dryer’s power draw varies as the compressor, freezer, heater, and pump cycle on and off.
I’ll list the processing times and power draws of a few different batches below. We’ve actually processed a lot more batches since these, but we’re no longer tracking the power draw since everything seems to be working fine.
By the way, the unit we purchased (medium) has four trays.
Batch One (18.30 hours):
Beef meatballs (1”-1.5”)
Blueberries (whole) shared tray
Raspberries (halved) shared tray
Batch One Process
Cooling chamber (Precooling cycle) 15 minutes at 4.8 AMPs (550 watts)
Freezing Cycle 3:25 hours, ranged from 3.7 AMPs (440Watts) to 4.1 AMPS (480 Watts)
Vacuum Freezing Cycle 15 minutes, 10.3 AMPs
Drying Cycle (this is the longest cycle) 14:15 hours ranging from 6.8 AMPs (812 Watts) to 13.1 AMPs (1560 Watts)
Batch Two (16:20 hours)
Strawberries (halved) 2 trays
Apples (sliced) 2 trays
Batch Two Process
Cooling chamber (Precooling cycle) 15 minutes at 4.5 AMPs
Freezing Cycle 3:5 hours, ranged from 3.6 AMPs (435Watts) to 4.0 AMPS (468 Watts)
Vacuum Freezing Cycle 15 minutes, 10.2 AMPs
Drying Cycle (this is the longest cycle) about 12 hours ranging from 6.8 AMPs (812 Watts) to 13.1 AMPs (1560 Watts)
Batch Three (16:13 Hours)
Shredded Cheese (5.5 lbs)
Batch Three Process
Cooling chamber (Precooling cycle) 15 minutes at 4.3 AMPs (515 Watts)
Freezing Cycle 3:15 hours, ranged from 3.8 AMPs (454Watts) to 4.0 AMPS (480 Watts)
Vacuum Freezing Cycle 15 minutes, 10 AMPs
Drying Cycle (this is the longest cycle) about 12 hours ranging from 6.6 AMPs (800 Watts) to 13.6 AMPs (1600 Watts)
As you might have noticed, the unit follows the same general trend throughout each of the three batches, regardless of the food type. The drying cycle produces the heaviest draw and is the longest cycle, although the draw varies - it’s not a continuous heavy draw.
Processing duration is the real variable, as drying herbs (6 hours) takes way less time than drying 60 eggs (20 hours)! BTW, mix your eggs before freeze drying so the yolks (which contain the fat) mix with the whites. Pure fat doesn’t freeze well.
The more liquid, the longer processing time.
Food Storage and Reconstituting
The Harvest Right freeze dryer we bought came with a small assortment of Mylar food storage bags as well as a bunch of 700cc oxygen absorbers (OA). In my opinion, the bags were pretty tiny, especially considering the magnitude cc of OA that came with them!
Fortunately, I have my own bags from PackFresh America and I also like to preserve a lot of food in my (old school) Ball Jars, using OAs, of course. Jars are way easier to stack and I kind of like seeing my food, too. I keep them in the root cellar which is cool and dark. Everyone has to choose what works best for them, depending on their storage situation.
I should also mention that the dryer came with a heat sealer for the Mylar bags which is very solid and impressive. Overall, the whole unit is extremely well-crafted and easy to use. It comes with a vacuum pump, extra oil for the pump, and copious instructions. I have nothing negative to say about the product and I’d definitely recommend it, as long as you’re going to use it enough to justify the initial cost.
Regarding reconstituting, Rehydration Calculations Made Easy by Wanda Bailey Clark is a very user-friendly guide to reconstituting freeze-dried, dehydrated, and powdered foods. The book features both Imperial and Metric measurements (just flip it over - very clever!).
I hope our experience has been helpful to you. Also, if you know someone who’s trying to decide whether to make the investment in a freeze dryer, please share this with them, too. We’re not getting any kickbacks from Harvest Right… In fact, we’re not monetized in any way. We just want to share what we’ve learned - especially if it means helping someone avoid mistakes we’ve already made!
As always, questions and comments are welcome.