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Dehydrating foodstuffs with the Anova Precision Oven (APO)


TdeV
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I've been posting questions in the APO topic and the Food Dehydration topic, so I thought to join them together. Here's some history of various discussions:

 

Now I have a total of 5 racks for my APO, 3 are a recommendation from @palo who said "They fit perfectly, smoothly slide in and out of the grooves and are rigid enough that there is no concern of them popping out of the grooves." Via Amazon, here for Canada and Australia, and here for the US. For the two racks which came with the APO whose rungs are too wide to support drying food, I got Silpats which have tiny holes in them; this was a recommendation by @JoNorvelleWalker, and do the job perfectly.

 

I don't yet have a solution for containing a 1/4" thick layer of veg or fruit in an applesauce-consistency (which will be dried into a "fruit leather"). I've asked DH to construct something which uses a sheet of parchment paper, but he raised his eyebrows dubiously, so we'll see. I have two quarter sheet pans which would do in a pinch, but which won't use the oven space efficiently.

 

The only APO published recipe comes from Scott Heimendinger (Anova) for dehydrating apple chips where he only uses heat on the bottom of the oven. Dehydrating multiple racks means some goo drops to the bottom of the oven which produces jam on the heating element. Does putting the tray over the lower heating element reduce the oven's efficiency? Should the heat source be changed to the rear element? Here's my request on the subject but no answers yet.

 

Resources and recipes:

Mary T Bell: Complete Dehydrator Cookbook (eG-friendly Amazon.com link) and Food Drying With an Attitude (eG-friendly Amazon.com link)

@Okanagancook recommended this https://www.excaliburdehydrator-recipes.com/

 

The APO door needs to be propped open to dehydrate foodstuffs. I have learned that a chopstick (~1/4") is enough space and a skewer (~1/8") is not enough. With the latter (skewer), I opened the oven in the morning (after 12 hours) and all surfaces on the door were full of water and the zucchini were still soft and wet.

 

Here's a discussion of my experiment with marinated zucchini.

 

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@kayb  @Okanagancook @andiesenjiand Everyone,

 

Do you seed roma tomatoes or any other kind of tomato before dehydrating?

 

It seems Mary T Bell recommended drying herbs (in this case basil) at a lower temperature (90°F/32°C) to keep more of the essential oils. My Anova Oven (with the door cracked open) has been at this for 18 hours and the basil is drier but not dry, i.e. still limp. Should I change strategy?

 

Mary Bell also recommends taking all the fat out of ground meat with paper towels, removing all the fatty tissue from other meats and fish, as well as using zero fat yogurt, methinks because, in longterm shelf life, anything with fat might go rancid. I'm not planning on (ever) doing any backpacking with dehydrated foods, so do I need to adhere to these rules?

 

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3 hours ago, TdeV said:

@kayb  @Okanagancook @andiesenjiand Everyone,

 

Do you seed roma tomatoes or any other kind of tomato before dehydrating?

 

It seems Mary T Bell recommended drying herbs (in this case basil) at a lower temperature (90°F/32°C) to keep more of the essential oils. My Anova Oven (with the door cracked open) has been at this for 18 hours and the basil is drier but not dry, i.e. still limp. Should I change strategy?

 

Mary Bell also recommends taking all the fat out of ground meat with paper towels, removing all the fatty tissue from other meats and fish, as well as using zero fat yogurt, methinks because, in longterm shelf life, anything with fat might go rancid. I'm not planning on (ever) doing any backpacking with dehydrated foods, so do I need to adhere to these rules?

 

 

No, I don't seed. I slice the Romas crossways, cherry or grape tomatoes in halves or quarters, depending on size, sprinkle with salt, drizzle with olive oil, and go. Have taken a flyer at drying herbs (sage), and it seemed to work OK.

 

On the tomatoes, if I'm doing a lot, as I slice I lay on paper towel covered racks and salt them there, to let them drain a bit, then move to the dehydrator trays. On my cheapie Ambiano, a round plastic model, I think it may have taken between 24 and 36 hours. Don't recall how long the herbs took.

 

55 minutes ago, TdeV said:

Also, has anyone cooked beans (e.g. Rancho Gordo) and then dehydrated them?

 

Never tried. I've soaked chickpeas, then dried off with a towel, tossed in olive oil and seasoned, and roasted them (200 or so for 3-4 hours), though. Nice snack.

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Don't ask. Eat it.

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  • 3 months later...
On 8/7/2021 at 2:22 PM, TdeV said:

The only APO published recipe comes from Scott Heimendinger (Anova) for dehydrating apple chips where he only uses heat on the bottom of the oven. Dehydrating multiple racks means some goo drops to the bottom of the oven which produces jam on the heating element. Does putting the tray over the lower heating element reduce the oven's efficiency? Should the heat source be changed to the rear element? Here's my request on the subject but no answers yet.

 

In the spreadsheet posted by @JasonsCookingAdventures, plums are dehydrated in a Miele combi-oven using the convection setting. I'm going to try the rear element when I dehydrate figs in my APO. Hopefully that makes propping the door open unnecessary. 

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@cyalexa, so far I have found no difference (in the time required to dehydrate food) between turning on the bottom element or the rear (convection) element. I would like to suggest, however, that propping open the door will speed up getting rid of the moisture. (But I don't know that for a fact, as I have not tested it).

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Addendum: I actually have dehydrated quite a few fruit and veg this summer and fall. I have lots of handwritten notes, so I will try to focus on writing up my experiences. And I've certainly got some photos.

 

 

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Perhaps one of my most interesting dehydrate/rehydrate discoveries is peppers, including green bell peppers. (Sorry @rotuts).  When dehydrated, much volume is lost. The rehydrated pepper doesn't rehydrate fully and, even after a bit of cooking, is still quite leathery, so it doesn't disappear like a regular pepper would. Also when using the dried peppers, I have a tendency to throw quite a bit (1/3 to 2/3 cup) into the beans or soup or stew. This results in a very strong bell pepper flavour which I find very tasty!

 

In a full Instant Pot I might also add 1+ tablespoon of dried poblano pepper.

 

Yesterday at the farmers' market I bought 3 pounds (1.4 kilo) green bell peppers and a quart (litre) of small colourful bell peppers. This created 3 trays of green bell pepper and 1 tray of colourful bell pepper.

 

IMG_3710_cropped.thumb.jpg.0ca4b8cfa4bdc9495aef0290775d88a9.jpg

 

Fresh, the colourful pepper tray had about half the volume of one tray of green bell pepper (which was also cut into twice larger dice). This is the tray after it had dried overnight. 

 

IMG_3709_cropped.thumb.jpg.b51c4fae8af0e288314ec7a8a7753b93.jpg

 

This 600 ml jar contains all of the dehydrated green bell pepper. It's about 2/3 full (couple dessicant packs in there).
So that's 1.4 kilo = 400 ml. You can see there is quite a significant reduction!

 

IMG_3712_cropped.thumb.jpg.a1cd3ebf5844583cb91eef02bd34c57d.jpg

 

 

 

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IMG_3718_cropped.thumb.jpg.e5aa3c3a9deca4c812a19eb8efc3e997.jpg

 

4-12 oz packets of fresh cranberries (from Wisconsin) were processed according to Spruceeats' advice (boiling water, then tossing and soaking with 1 cup sugar syrup) (link).

 

The process of pouring boiling water on them, leaving to soak, then stirring now and again, meant that the berries were very unevenly "cooked." Many of the berries did not collapse. This necessitated my poking every darn one with a knife. Does anyone have a shortcut for this? Photo above is the dividing line between already- and not-yet-poked.

 

Cranberries were placed on a purée sheet (with a lip) because they were rolling everywhere. Spruceeats said to keep 1/2" space surrounding each cranberry. Ha ha ha ha! I'm thinking they might collapse by tomorrow, then I can transfer them to Silpat sheet.

 

 

Here they are as they went in the APO at noon today (Thanksgiving).

 

IMG_3723_cropped.thumb.jpg.2a35aad0d78265fe1f70e2c761796bbe.jpg

 

Does anyone have experience dehydrating cranberries? How have you handled the uneven cooking?

 

Did you find it was worth the trouble?

 

 

 

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  • 6 months later...

This is half of today's capture of fresh strawberries from the farmers' market. I also got rhubarb (which I will also dehydrate) and broccoli raab (which I will not). 126°F (52°C) for 6-8 hours. If the berries are not dry tonight, I'll plan to freeze them semi-dry on the morrow.

 

IMG_4118Sm.thumb.JPG.45c99a4a9e8bc25ccd98358d268384a3.JPG

 

 

 

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These are all the strawberries after ~7 hours. They're dry on the outside but still fairly squishy. Went back into the APO this morning.

 

IMG_4120Sm.thumb.JPG.434df6a9722d6e27910a3b97d02c4f55.JPG

 

 

Following the Gangloff book, the rhubarb was dipped in boiling water for 75 seconds. This rhubarb is mostly green. It's okay to eat, yes?

 

IMG_4123SmCropped.thumb.jpg.6858a0506ce85e832207c9b8726f19f6.jpg

 

 

And, there's still room, so I threw in these tired bananas. I put a heaping tablespoon of citric acid into a bowl, then dipped in the bananas.

 

IMG_4127Sm.thumb.JPG.a5610c2e6d8587c51b5db0e41ce2328f.JPG

 

These photos are not mounting the same way I see them, but I don't know why.

 

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  • 4 weeks later...

No picture, sorry, I just thought to mention my disaster.

 

Friday I had a pretty ripe cantaloupe, part of which got used as melon + prosciutto appetizer, balance sliced into 1/" - 3/4" slices which rested on the Silpat mats until about 6 p.m. whereupon the trays were added to the APO at 125°F/52°C.

 

Next morning I opened the oven, to see if they were dry (almost, but not yet) and decided to eat the one I'd squished. Turning it over, I saw it was covered with black mould. So I turned over the rest. Almost all with mouldy spots. Sadly, all the pieces were tossed in the trash.

 

Which was a shame. The one I ate had a lot of flavour with a whisper of sweetness.

 

Good idea, faulty execution. What I should have done was a bath with a splash of lemon juice or acetic acid.

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