Hakasays' non-OU-related projects

[Hakasays]

Freeze-drying experiment



This one's sort of a day-project.  I just got a bunch of dry ice this morning and so I can start the first phase of a freeze-drying experiment.

The first stage is pretty simple, I just threw a bunch of ice cream sandwiches and some fresh berries in the dry ice pile to supercool below the H2O sublimation point.

After a couple hours it should be cold enough to transfer to the vacuum chamber, then it's just pumping air(and water) out for a number of hours.
In a vacuum below a certain temp, water goes straight from solid to gas, so you can dehydrate products without a dehydrator.

Once it's going, the evaporation is endothermic so the sublimating ice inside the products in the chamber should keep the product temperature below the sublimation point throughout the whole process.

Might have results today, but I'll probably let it run overnight to be safe.

[Hakasays]

Well, the good news is the vacuum pump did succeed at removing most of the water.
The bad news is that it looks like the evaporation was not fast enough to keep the temperature below the sublimation point throughout the process.  So it lost its structure as it was liquid when it 'boiled' off.

Still interesting because the water still got pulled out; the ice cream sandwiches are almost flat as most of the water was sucked out.


For future experiments, I guess I will have to find a way to keep everything well below freezing throughout the whole process.  Or possibly resolved with a more powerful pump and greater insulation for the first 12hrs (unlikely).
The next time I test this, I think I'll try to find some thin vacuum tubing and leave the vacuum chamber in a regular freezer to hold the food below freezing while the water gets sucked out.

[Hakasays]

On the plus side, I had WAY more dry ice than I needed to do the freeze-dry project, so I grabbed some milk+cream and tried making instant ice cream with it.  First try, so I just eyeballed a few recipes online and went from there.🤠

Milk+Cream+Sweetened condensed milk + vanilla.

For the dry ice, I just blended the pellets for a few seconds to make 'snow' and add spoonfuls at a time to the cream to freeze it quickly.

Foamed over a TON so I lost some of the first batch to the floor+sink.  Oh well, lesson learned.   After a few tries I think I have the technique pretty well down now.

Made almost 2 gallons in the span of like 15 minutes.   Crazy fast.👍😁

10/10 would recommend as an interesting family/holiday activity.

[Chet K]

 Cool .....

[Hakasays]

Cool .....

One thing that surprised me was how little dry ice is actually needed to freeze water.  Only a few pounds made over a gallon of ice cream.
I lost more dry ice overnight due to evaporation than it actually took to make the ice cream