Freeze Drying Mistakes 1 – Mixing Raw Meat with Other Foods
Just like in the rest of the kitchen, you want to avoid cross-contamination to prevent the spread of e Coli and other bacteria.
Scientists use freeze-drying to preserve bacteria samples. This means your odds of any bacteria on your raw meat surviving the freeze-drying process are pretty high.
During the freeze-drying process, water vapor moves around the freeze-drying chamber. (The sublimation process takes the water in the food from frozen to vapor, skipping the liquid state.)
Please don't mix foods like fruits and vegetables that are intended to be eaten raw with raw meat.
If you wouldn't mix the foods on a kitchen cutting board, don't mix them in the freeze-drying chamber.
Freeze Drying Mistakes 2 – Mixing Foods with Dissimilar Flavors
There are a number of sources that say you can mix and match even strong-flavored foods in the vacuum chamber, as long as you put the strong-flavored food (like onions) on the top shelves. I'm telling you otherwise.
Maybe those folks have wonky taste buds, but when we freeze-dried green beans and bananas in the same batch of food, we ended up with green bean flavored bananas.
The flavor was subtle, but it was definitely there (and green bean bananas do taste as bad as they sound).
Since then, we've been careful to keep sweet and savory foods separate, with good results.
Freeze Drying Mistakes 3 – Attempting to Freeze Dry High Sugar Foods
Some foods like very high sugar content fruit, jams, or jellies do not freeze-dry well. No matter how long you leave them in, they will still be a little (or a lot) sticky. This is because sugar binds to free water molecules, preventing them from escaping the food. Normally, this trait is helpful for food preservation. Binding up free water slows down bacteria and mold growth because those microorganisms need water to thrive. Unfortunately, it results in a less than ideal freeze-dried product.
How much sugar is too much sugar? The good news is that most plain fruit still works very well, although sweeter fruits like peaches or pineapple will likely require a longer drying cycle.
The only fruit I've tried so far that took a very, very long time and still came out tacky was pears. There's a reason I refer to my dehydrated pears as "pear candy".
I'll stick to dehydrating those since the freeze-dried pears came out very similar in texture to the dehydrated pears. Just skip the jams, jellies, and other fruit spreads.
Freeze Drying Mistakes 4 – Trying to Dry High Fat Foods
One of the first freeze dryer reviews I read was from a fellow who attempted to freeze-dry butter. He ended up with a massive mess. There was butter coating on every surface on the interior of his freeze dryer, and it took a very long time and lots of work to clean up.
Of course, this got me wondering how much fat is too much fat, so I tried some pre-cooked, frozen breakfast patties. Never again – at least not unless I heat them up and remove as much fat as absolutely possible before freeze-drying.
Like the first gentleman, I ended up with fat coating much of my freeze dryer. Even after a good scrubbing, it took weeks for the odor to fade completely. (Thankfully, other foods did not pick up the odor.)
The flavor of the finished product was a lot like sausage jerky, and they didn't rehydrate very well (see next mistake). Still, if you were hungry, I'm sure they'd be delicious.
Fat will also go rancid more quickly than other food items, so a meat or dairy product with higher fat levels is probably best used within 5 years. Make sure that if you want to freeze dry meat products that as much fat as possible is removed before drying. Full-fat dairy such as whole milk, sour cream, and cheese work just fine.
