Jump to content
  • Welcome to the eG Forums, a service of the eGullet Society for Culinary Arts & Letters. The Society is a 501(c)3 not-for-profit organization dedicated to the advancement of the culinary arts. These advertising-free forums are provided free of charge through donations from Society members. Anyone may read the forums, but to post you must create a free account.

Kerry Beal

Freeze Driers and Freeze Dried Food (Part 1)

Recommended Posts

Kerry, what's the company in Utah from whom you bought the unit? I've got to admit, I'm enticed by the idea of being able to freeze dry anything I want.

Share this post


Link to post
Share on other sites

Kerry, what's the company in Utah from whom you bought the unit? I've got to admit, I'm enticed by the idea of being able to freeze dry anything I want.

It's called Harvestright - here is a link.  

  • Like 1

Share this post


Link to post
Share on other sites

Ok - first batch is in!

 

A tray of nice ripe banana slices, a tray of mini ice cream sandwiches, a tray of regular sized neapolitan ice cream sandwiches and a 1 kg container of frozen Boiron mango puree cut into 1/2 inch slices.  I pre cooled the FD'er for about an hour, then dialled it up to 11 hours cooling.  Apparently ice cream sandwiches should be frozen to -40 C until thoroughly frozen through - if their centres are warmer they tend to puff up when the vacuum starts and it makes them ugly.

  • Like 5

Share this post


Link to post
Share on other sites

I'd love me a freeze drier just for the strawberries!  :biggrin:


~Martin :)

"Unsupervised, rebellious, radical agrarian experimenter, minimalist penny-pincher, self-reliant homesteader, and adventurous cook. Crotchety, cantankerous, terse, curmudgeon, non-conformist, and contrarian who questions everything!"

The best thing about a vegetable garden is all the meat you can hunt and trap out of it! 

 

Share this post


Link to post
Share on other sites

Checked on the FDer this am - still has about 1 1/2 hours on the freezing part of the cycle before the vacuum pump kicks in and the shelf heaters start to do their thing. 

 

A fair amount of condensation on the door of the unit - beginning to understand some pictures that Chocolot sent me showing one of the trays under the door!  Mine now has a stainless Air Canada tray in the same location.  

 

The drying part of the cycle is set for 5 hours - but it will take much longer than that.  What happens is that the pump cycles on and brings the vacuum down to a certain level.  The shelf heaters then cycle on and water starts to sublimate out of the food.  Eventually the pressure rises due to the additional moisture and this causes the heaters to cycle off and the vacuum pump to cycle back on.  The timer resets over and over during the process.  So 5 hours could be anywhere between 12 and 24 hours by the time the microprocessor is satisfied with it's readings (or the water on the condenser overwhelms the unit and you have an endless cycle of melt and freeze on the condenser).  

Share this post


Link to post
Share on other sites

Im wondering if you might consider freeze-drying some wine.  one you might drink say ....

 

then use the concentrate as a wine flavoring.   Im wondering if the water and EtHO might be removed but the various flavor

 

components left behind   

 

this should be very very low on your list of experiments.

Share this post


Link to post
Share on other sites

Re FD wine...I bet a lot of volatile flavor would go off too.

 

When I lyophilized stuff in the lab (decades ago) , I would always freeze it first with LN2 or dry ice/acetone. This Freeze-Girl (relative of Steam Boy) seems like it takes a long time to get to frozen; why not pre-freeze?

Share this post


Link to post
Share on other sites

Thinking that alcohol in the wine is likely to be removed in the process - I would assume that even frozen the boiling point of ETOH is lower than that of water - and I think the sublimation temperature would be as well.

 

Doesn't mean I won't do the experiments though!  

 

Do need to get some dry ice or liquid nitrogen for pre freezing things for sure.  Or maybe an anti griddle?

Share this post


Link to post
Share on other sites

""  an anti griddle  ""

 

:biggrin:

 

in for a pound .....

 

I had assumed the FD wine would not work.  Id be interesting in wine w the water and EtOH removed, but the 'rest' left.

Share this post


Link to post
Share on other sites

Freezing point of EtOH is about -115C. LN2 could freeze it, but the Freeze Girl couldn't hold it there. I believe it would boil off rather than sublimate.

 

The volatiles in wine that contribute to what you smell would have to be lost by the process I think.

Share this post


Link to post
Share on other sites

I love how Kerry gets us all involved:) Off to Salt Lake City I go in search of her treasure. The guys at HarvestRight are really nice. They gave me the tour of the plant. It appears to be very well made and I reported back to Kerry. Next thing I know, the crazy woman has ordered one!! The best part is now I have an "in". I take things down and they dry them for me. So far I have taken leftover ganache-I had visions of it just being poured on a tray, but somehow they managed to made mounds out of it. I tried rehydrating a piece. Not really successful. Next I will turn into a powder and try again. They have done cooked bacon--great for breaking up and putting on my Maple-Bacon piece for an upcoming Cowboy Festival. Fresh sliced peaches are wonderful. I turned them into a coarse powder and will make a peach-almond ganache. They gave me mini ice cream sandwiches that I enrobed in chocolate and returned to them. Very tasty, much like a crisp cookie. They gave me raspberries that I played with. I'll post a pix. I enrobed strawberries. I actually like them better than fresh, but then I am not a fan of strawberries in chocolate.  I want them to do cream cheese--they said it works great. I will turn into a powder and make a cheesecake ganache. About the only thing they said doesn't work is butter. It just melts.

We are lucky to live in a desert. The humidity here is usually under 15%, except today it is 100%:). The products will try to rehydrate if left out in the open.  They gave me some pulled pork to play with. I was thinking of doing a pork and bean ganache--don't judge me!!! It was for the Cowboy Festival! I thought the pork might work. I decided against it and just ate the pork in a BBQ sauce. Very nice. I took down leftover peeps. They look the same, but taste like sweet styrofoam. 

I don't now how much longer the guys will FD things for me before expecting me to buy, but I keep taking them chocolate, so it might work for a while.  It will be fun to see what Kerry comes up with.

IMG_3154.jpg

  • Like 2

Ruth Kendrick

Chocolot
Artisan Chocolates and Toffees
www.chocolot.com

Share this post


Link to post
Share on other sites

Re FD wine...I bet a lot of volatile flavor would go off too.

 

When I lyophilized stuff in the lab (decades ago) , I would always freeze it first with LN2 or dry ice/acetone. This Freeze-Girl (relative of Steam Boy) seems like it takes a long time to get to frozen; why not pre-freeze?

I did pre freeze too - in my upright freezer.  I need to get it cleaned out and defrosted so things can lie flat on the shelf to freeze - especially before I get into stuff like cream and milk. 

Share this post


Link to post
Share on other sites

Got home from work last night - Freeze-Girl had 2 hours of drying left - decided to pull everything half an hour before that as I had to work again this am.  

 

Turned off machine, opened the drain hose to allow air back into the unit.  Shelves and product were warm.  

 

The bananas and ice cream bars were completely dry - the mango puree still had dampness at the center.  I bunged that tray back into the deep freeze to put in on my next run to finish it off.  I suspect my 1/2 inch slices were perhaps a little thicker than that!

 

I allowed the unit to defrost overnight - this am there were a couple of litres of water in the drain bucket.

 

Put the various things into vacuum bags with an O2 absorber and heat sealed closed.  

 

 

IMG_1568.jpg

 

Banana slices - nice and ripe!  Will be excellent as flavouring in a banana filling I think.  

 

IMG_1569.jpg

 

Mini ice cream bars - think I'll dip a couple of these in some dark chocolate with the addition of 4% butter fat to soften the chocolate a bit.  

 

IMG_1571.jpg

 

Standard sized neapolitan bars.  Brought a few to work this am - they seem to be popular.

 

 

 

  • Like 3

Share this post


Link to post
Share on other sites

That looks like a lot of fun, Kerry, and I want one of those ice cream sandwiches after you're dipped them. At some point I hope you'll check the water to see what it's like.


Nancy Smith, aka "Smithy"
HosteG Forumsnsmith@egstaff.org

"Every day should be filled with something delicious, because life is too short not to spoil yourself. " -- Ling (with permission)

"There comes a time in every project when you have to shoot the engineer and start production." -- author unknown

Share this post


Link to post
Share on other sites

Yes, I'm curious about whether some volatiles end up in the water - enough to give it useful flavour. If it's more like distilled water I could imagine using it for watering plants or other household uses in an arid climate, but that hardly applies to your part of the world.


Nancy Smith, aka "Smithy"
HosteG Forumsnsmith@egstaff.org

"Every day should be filled with something delicious, because life is too short not to spoil yourself. " -- Ling (with permission)

"There comes a time in every project when you have to shoot the engineer and start production." -- author unknown

Share this post


Link to post
Share on other sites

I'm definitely talking to you before my next camping trip, Kerry!

  • Like 2

MelissaH

Oswego, NY

Chemist, writer, hired gun

Say this five times fast: "A big blue bucket of blue blueberries."

foodblog1 | kitchen reno | foodblog2

Share this post


Link to post
Share on other sites

Yes, I'm curious about whether some volatiles end up in the water - enough to give it useful flavour. If it's more like distilled water I could imagine using it for watering plants or other household uses in an arid climate, but that hardly applies to your part of the world.

Water was minimally fruity.

  • Like 1

Share this post


Link to post
Share on other sites

Tonight I'm going to start the next batch. 

 

On the first tray I have the mango puree that was still a bit damp last time - I mentioned I had put it back in the deep freeze to wait for tonight's run.  

 

IMG_1572.jpg

 

Some shredded cheddar.

 

IMG_1573.jpg

 

Tomatoes from my garden.

 

IMG_1574.jpg

 

Liberty greek yogurt with honey - got a couple of those old fashioned ice cube trays with the lever but made from stainless, lined them with parchment.  

 

Also added to the half empty tray are some mini marshmallows.  

 

IMG_1575.jpg

 

I dipped some pieces of the larger ice cream bars in dark chocolate (with the addition of some butterfat for softness).  

 

IMG_1576.jpg

 

Lots of shattering happened so made some bark with the remains.  

  • Like 2

Share this post


Link to post
Share on other sites

I am tempted to take some time off work and head down to your neck of the woods to try some of that bark!  Very hard to not want some delicious chocolate bark for breakfast now :wink:

 

What do you use as an oxygen absorber for your vacuum sealed products? 

Share this post


Link to post
Share on other sites

I used to do a lot of freeze-drying (lyophilizing) in the lab, but in the format where frozen solutions are externally attached to the manifold or chamber-(platform) leading to the condensating drum.  Typically one used dry-ice/acetone (this was adequate) or liquid nitrogen to rapidly freeze the solution while creating maximal surface area for the sublimation by rotating the flask.  Cooling done to the temperature of the cooling bath.  Solutions of water-soluble peptides, proteins, immunogens, protein-drug conjugates, other water-soluble substances/molecules, that sort of thing.  If organic co-solvent was present one removed most of it first on a rotovap before freezing and lyophilizing.  Vacuum on the freezemobile was not applied until the drum was at least -30ºC.  Vacuum was preferably at less than 100 mT, but "several hundred" mT was adequate.  Ambient heat was sufficient to drive the sublimation; the outside of the vessel would "freeze over" with atmospheric water vapor and insulate the vessel sufficiently so that heat transfer from the surroundings was slow enough to maintain the internal temperature well below the melting point; in fact the temperature of the "ice layer" around the flask would frequently be a fair bit below 0ºC and this ice layer would not melt until the lyophilization was nearing the end and water sublimation was ceasing.  But perhaps folks in MClabs know all this?

 

The freeze-dryer you have is the sort more common in the food industry and in pharmaceutical or medical scenarios - e.g. freeze-drying multiple vials of (aqueous) vaccine, medical formulations, etc - as you well know.  The sort of freeze-dryer used in chemistry and biochemical labs tend to be of the sort I described - like this one or this one - just so folks know there are two basic formats for the process.


Edited by huiray (log)

Share this post


Link to post
Share on other sites

I have followed a lot of those manifold freeze driers over time on ebay - as well as the chamber ones used for flowers and taxidermy!  Saw one in the place I picked up an old stokes candy pan - wasn't prepared for it at that time!  Nor did I have room in the car (it was in New Jersey).

Share this post


Link to post
Share on other sites
Guest
This topic is now closed to further replies.

  • Similar Content

    • By RioRichard
      Hi. Found this forum via a search engine regarding home freeze drying.  Thanks for adding me to the community.
      We are about 6 weeks into exploring this addictive process and try to run it as often as possible with a variety of meats, vegetables and other good stuff (lets not forget ice cream sandwiches).
      Located in the Little Rock, AR area. Looking forward to sharing experiences.
    • By Mr. Mike
      CALLING ALL FREEZE DRYER OWNERS:

      Project: Freeze Drying: A Quick reference guide for Tips, Hints and FAQ’s for Freeze Drying. i.e. Collector document.

      As part of trying to organize all the different questions and topic discussed, I made a proposal to organize the different topics for new and seasoned owners for their results and experiences in using our freeze dryers.

      We have support from the higher ups for organization, editing and posting this Freeze Drying Reference Guide.

      Food drying is ONE of many topics that will be addressed in this reference guide.

      Next: an outline for the Food drying results section.


      Mr. Mike
       
    • By Teppy
      Well, I've been trolling eBay for a while now, and finally found one of these beasts in good condition at a reasonable price. Now the fun starts...
      I'm brainstorming ideas on what to do with it. Gourmet astronaut ice cream? Crispy cheesecake? Some weird variant on beef jerky?
      What else?
    • By TonyC
      Host's note: this topic is continued from Freeze Driers and Freeze Dried Food (Part 1).
      Hello everyone,
      We are new to this discussion having just purchased and rec’d our freeze dryer a week ago. I have read with interest the exploits from all of you over the last 20 pages and simply want to thank all the participants for sharing their knowledge.
      We have now completed our 7th batch of freeze dried food with great success (thanks in no small part to the knowledge obtained here). It has inspired me to give back as well. I have two thoughts to contribute to this discussion. The first is a warning and the second is an observation.
      First the warning – Botulism
      For anyone who has canning experience beyond making jams or jellies, you know the dangers of botulism. We use pressure cookers and proven recipes to insure we kill the bacteria before we can our food. These recipes include not only the ingredients, but the cooking pressure and the minimum time to cook the food. The “USDA Complete Guide to Home Canning” is the bible when it comes to this method of preserving food. A quick google search will turn of quote above will get you to the guide.
      Why am I bringing this up? Because the bacteria that causes Botulism thrives in an oxygen deprived moist environment. Putting away food that is not completely freeze dried in Mylar bags or canning jars by pulling a vacuum or using O2 packets can potentially put you and your family at serious risk.
      With the above said, we have successfully vacuum sealed dry staples for years by simply pulling a vacuum. We have also canned meats and stews with pressure cookers successfully, but we have always erred heavily on the side of caution. I urge you to do the same when you freeze dry your food. Err on the side of longer cycles to insure that the food you remove is completely dry (under 5% moisture content – the lower the better). If any of your freeze dried food has a frozen center and you store it in an oxygen free environment, you are putting yourself and your family at risk. Botulism is odorless and tasteless. And you won’t know that you are infected until you are ill. This is serious!
      From Wikipedia
      Botulism is a rare and potentially fatal paralytic illness caused by a toxin produced by the bacteria Clostridium botulinum. The disease begins with weakness, trouble seeing, feeling tired, and trouble speaking. This may then be followed by weakness of the arms, chest muscles, and legs. The disease does not usually affect consciousness or cause a fever.[2]
      Botulism can occur in a few different ways. The bacterial spores that cause it are common in both soil and water. They produce botulinum toxin when exposed to low oxygen levels and certain temperatures. Foodborne botulism happens when food containing the toxin is eaten.
      Prevention is primarily by proper food preparation. The toxin is destroyed by heating to more than 85 °C (185 °F) for longer than 5 minutes. It is not recommended to give honey to children who are less than one year of age due to the risk with this food. Treatment is with an antitoxin. In those who lose their ability to breathe on their own, mechanical ventilation potentially for months may be required. Death occurs in 5 to 10% of people.
      In all cases, illness is caused by the botulinum toxin produced by the bacterium C. botulinum in anaerobic conditions, and not by the bacterium itself
      Improperly preserved food is the most common cause of food-borne botulism. Fish that has been pickled without the salinity or acidity of brine that contains acetic acid and high sodium levels, as well as smoked fish stored at too high a temperature, presents a risk, as does improperly canned food.
      Foodborne botulism results from contaminated food in which C. botulinum spores have been allowed to germinate in low-oxygen conditions. This typically occurs in home-canned food substances and fermented uncooked dishes.[10] Given that multiple people often consume food from the same source, it is common for more than a single person to be affected simultaneously. Symptoms usually appear 12–36 hours after eating, but can also appear within 2 hours to 10 days.
      Although the botulinum toxin is destroyed by thorough cooking over the course of a few minutes,[19][20] the spore itself is not killed by the temperatures reached with normal sea-level-pressure boiling, leaving it free to grow and again produce the toxin when conditions are right.
      2nd The Observation
      Being the curious sort that I am I placed an Accurite Thermometer in my Freeze Dryer to see what was going on inside this great little box. I followed the cycles through the Freeze cyle and into the two hours into the Vacuum cycle I had previously moniotored the 3rd phase. I was surprised by what I found and had to go do some reading on freeze drying techniques to begin to understand what was happening.
      I set the cooling cycle to 10 hours so I could achieve maximum cooling. Post Dry time was set to 12 hours.
      See my observations in the table below. The temperature probe was placed behind the insulation disc seated on the bottom of the cylinder in front of the trays. I secured the temperature gauge to the door with a magnet. It was within inches of the sending unit inside the chamber.
      I wanted to know how long it took to reach maximum cooling. The answer is 8 hours.
      Best time to put in pre-frozen food? The answer is 1 hour. The temperature in the Freeze Dryer will be very close to the temperature of your freezer at that point.
      I was amazed at how fast the temperature dropped when the vacuum pump first kicked on. The temps literally dropped dramatically by 11F from -39F to - 50F in less than 2 minutes. There was a frost line completely around the bottom of my door gasket from 2 o’clock to 10 o’clock.
      I was equally amazed to see the internal temperature rise from -50F to +60F in 2 hours. The temps at the time in my garage were 62F.
      I surmise that the chamber walls stay well below freezing while the food dries out above freezing in a near vacuum. I set my freeze dryer to reach below 10 mT for a few hours before completion in the hopes that the almost complete vacuum helps to sublimate the moisture in the food.
      There is a great deal of engineering going on that I am not sure I completely understand. I fully expected to see temps well below freezing through all three cycles. This is obviously not the case.
      All this said, I love the function that the machine brings to me. I think better understanding of the strengths and limitations of the unit will aid each of us in setting our expectations realistically, and insures that we optimize the machine to its fullest. We all want freeze dried food that is nutritious, and safe to eat. Understanding the process will only help us make intelligent decisions.
      I hope my contributions are worth something to someone. Thanks again for this group leading the way.
      Kindest Regards, Tony
      Edited to change table to picture for proper viewing and cleanup text... I'm trying!


    • By Harky
      I'm having trouble finding these from the Texturas line from El Bulli (there's a couple recipes with them I want to make from www.albertyferranadria.com). Are the Lyo-Sabores just freeze dried fruit? Or do they use a different process?
  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...