We have some really great 'techy' type guys here who are, as they have been exploring the FD mechanics and sharing that in their posts, writing what is turning out to be a 'troubleshooting manual' for us less capable folks.
I honestly think putting a thermometer inside the unit is an excellent idea. I sent the following note off to Harvest Right Support in an effort to gain a little better understanding of the process.
Ideal vacuum pressure and drying temperature is maintained for each material and preserves freshness and potency
The only way I know to filter the water vapor out would be a cold trap. They usually use liquid nitrogen or dry ice to keep the temperature low enough that all the water condenses out. Obviously you would need a supply of the liquid nitrogen or dry ice that would probably not be cost effective for most of us. The other option to get that cold would be to use a cryocooler and build a cold trap around it. It could be done, but would be pretty expensive. I've been watching some electronics on ebay that have cryocoolers in them, but the cheapest I've seen is around $600. Still not a cheap option, but you wouldn't need dry ice or liquid nitrogen to feed it.
Reinstalled the vacuum hose and capped far end of hose to do a hose test. (same results as pump alone)
They come out as dry and hard as lumber. So, if you try to freeze dry a steak or roast, expect to break a tooth eating it.
Freeze drying is also simple to do – much easier than canning or dehydrating. If you care about having an emergency food supply, a Harvest Right Freeze Dryer is the best and most affordable way to do it.
A bit of background on me - I used to work in a sold state fabrication lab (university research lab) and had a lot of hands-on work with ultra-high vacuum equipment. The pumping we do for freeze drying was what was required to just start
It takes slightly extended to dry than our other picks, and it lacks a speed-dry option, but it surely gets the job accomplished and fees various hundred dollars under very similar dryers.
This does not address the food quality after that time, only the food safety. However, pelo real data exists on the shelf-life of home freeze-dried products, because the company that invented and manufactured website the first home freeze-dryer began sales in 2013.
This is why so many people are buying their own freeze dryers to use at home. The market is essentially cornered by Harvest Right, which isn’t a bad thing since their quality and customer service are both superb.
With simple-to-use dial controls and straightforward cycles, It truly is an excellent decision for those who dislike fidgeting with buttons and configurations.
The key is to freeze as fast as possible then dry as slow as possible. The freezing stiffens the cells so that when it is dried, it still maintains it's shape and texture.
You can also use Facebook Marketplace or specialty groups to find used freeze dryers, but most people will list them in specialized stores because that’s where most people will be looking.