Freeze-drying Jello gelatin with an improved cold trap
I built an improved cold trap from an aluminum pan and a stainless steel bowl. It held more ice than my original copper pipe cold trap, but the 100ml of water from the gelatin still managed to almost plug up the trap.
It would be possible and perhaps useful to make your own freeze-dried food for backpacking, but it would definitely not be economical. Even if you already had a vacuum pump, you will need dry ice, and the cost of the dry itself itself is probably higher than the pre-made freeze-dried food.
How much dry ice did you use to make the jello shown in the video? Also would the coolant loop out of a mini fridge be cold enough to make the cold trap?
Ok, now try making is as an aerogel- use as little water as possible, substitute absolute ethanol for the methanol- basically make the strongest jello shot you've ever tasted, then see what happens when you put it in the supercritical dryer....
Shawn, It took about 7 pounds of dry ice to keep the trap cold for 18 hours. Most of the heat leakage that causes the dry ice to sublimate occurs through the junction between the bowl and the rubber seal.
Have you considered making your heat trap easier to replace rather than better at dealing with the ice? If you just made 2-3 of your first design you could rotate them easily.
Why couldn't you use the alcohol-filler water cooler to condense the vapor? It would seem to enable a fairly large collection vessel that way. Would it not get cold enough?
Secondly, I googled the idea and saw many designs with the cold trap inlet entering from the top, axially centered in the chamber. If the inlet tube is insulated, the ice accumulation presumably would occur on the bottom surface of the vessel.
I'm picturing a stainless water bottle or some-such, cap machined with one insulated axial inlet and one offset outlet, submerged in the cool bath. If it doesn't make a stalagmite right to the inlet, might be good (in theory at least) for 20 oz. or so.
Why couldn't you use the alcohol-filled water cooler to condense the vapor? It would seem to enable a fairly large collection vessel that way. Would it not get cold enough?
Secondly, I googled the idea and saw many designs with the cold trap inlet entering from the top, axially centered in the chamber. If the inlet tube is insulated, the ice accumulation presumably would occur on the bottom surface of the vessel.
I'm picturing a stainless water bottle or some-such, cap machined with one insulated axial inlet and one offset outlet, submerged in the cool bath. If it doesn't make a stalagmite right to the inlet, might be good (in theory at least) for 20 oz. or so.
At the end you said something about freeze drying fruits. You might want to look on food networks site. Under 'Good Eats' he used Dry Ice, and a bowl and a ice chest to freeze dry his strawberries. It might give you ideas on how to go about it, and such, or there of, maybe it will spark something to make it better? Or Eaiser... *shrug* who knows. Any little inspiration might help in a thought process even if it isnt related at all.
what about using a diaphragm vacuum pump, no issues with the oil.
using zeolite or silica to air dry it, use a cartridge type to easy replace with another and dry it separately in the microwave for reuse.. should be more energy/environment friendly..
Great video. Do you think this could be used to economically produce home made freeze dried backpacking food?
ReplyDeleteIt would be possible and perhaps useful to make your own freeze-dried food for backpacking, but it would definitely not be economical. Even if you already had a vacuum pump, you will need dry ice, and the cost of the dry itself itself is probably higher than the pre-made freeze-dried food.
ReplyDeleteHow much dry ice did you use to make the jello shown in the video? Also would the coolant loop out of a mini fridge be cold enough to make the cold trap?
ReplyDeleteHow well does it rehydrate?
ReplyDeleteOk, now try making is as an aerogel- use as little water as possible, substitute absolute ethanol for the methanol- basically make the strongest jello shot you've ever tasted, then see what happens when you put it in the supercritical dryer....
ReplyDeleteShawn, It took about 7 pounds of dry ice to keep the trap cold for 18 hours. Most of the heat leakage that causes the dry ice to sublimate occurs through the junction between the bowl and the rubber seal.
ReplyDeleteHave you considered making your heat trap easier to replace rather than better at dealing with the ice? If you just made 2-3 of your first design you could rotate them easily.
ReplyDeleteWhy couldn't you use the alcohol-filler water cooler to condense the vapor? It would seem to enable a fairly large collection vessel that way. Would it not get cold enough?
ReplyDeleteSecondly, I googled the idea and saw many designs with the cold trap inlet entering from the top, axially centered in the chamber. If the inlet tube is insulated, the ice accumulation presumably would occur on the bottom surface of the vessel.
I'm picturing a stainless water bottle or some-such, cap machined with one insulated axial inlet and one offset outlet, submerged in the cool bath. If it doesn't make a stalagmite right to the inlet, might be good (in theory at least) for 20 oz. or so.
Why couldn't you use the alcohol-filled water cooler to condense the vapor? It would seem to enable a fairly large collection vessel that way. Would it not get cold enough?
ReplyDeleteSecondly, I googled the idea and saw many designs with the cold trap inlet entering from the top, axially centered in the chamber. If the inlet tube is insulated, the ice accumulation presumably would occur on the bottom surface of the vessel.
I'm picturing a stainless water bottle or some-such, cap machined with one insulated axial inlet and one offset outlet, submerged in the cool bath. If it doesn't make a stalagmite right to the inlet, might be good (in theory at least) for 20 oz. or so.
At the end you said something about freeze drying fruits. You might want to look on food networks site. Under 'Good Eats' he used Dry Ice, and a bowl and a ice chest to freeze dry his strawberries. It might give you ideas on how to go about it, and such, or there of, maybe it will spark something to make it better? Or Eaiser... *shrug* who knows. Any little inspiration might help in a thought process even if it isnt related at all.
ReplyDelete.
ReplyDeleteSome ideas and thoughts,
what about using a diaphragm vacuum pump, no issues with the oil.
using zeolite or silica to air dry it, use a cartridge type to easy replace with another and dry it separately in the microwave for reuse.. should be more energy/environment friendly..
Bruce
.
Have you thought about using something like a silica gel to absorb the moister?
ReplyDelete