Vacuum Infused Fruit (for Ice Cream)

A vacuum chamber can be used to infuse a liquid into food. By creating the vacuum, the pore space of food that is occupied by air, gets saturated with the liquid.

This instructable is a variant on the set-up presented by Noahw. Please look here (https://www.instructables.com/id/Vacuum_Infused_Fruit_Cocktails) for some more information and an excellent video.

The main pupose however is different: infusing chunks of fruit with a water-sugar solution so they can be mixed in ice cream.  The infused solution will partially act as a kind of anti-freeze resulting in fairly soft chunks of fresh fruit at low temperatures (freeze point depression, see also section 5 and 6).

The hardware is slightly different as well: the glass section of the door of a washing machine is used as a vacuum chamber.


UPDATE:
It has taken a while, but here's my first recipe: Sugar infused Apple-Cinnamon icecream

Step 1: What Do You Need?

1. The glass section of the door of a washing machine or any type strong glass (like Pyrex). Do not use any thin or poor quality glass as there is the risk of imploding the chamber!!!. Make sure it has a flat sealing face. Did I mention that following this instruction is at your own risk?

2. A wooden base plate (white MDF or any fairly solid type, 40x40x2 cm).

3. A gasket of the size of the glass bowl (green foil in the picture).

4. Two Aluminum pipes (length approximately 10 cm, outer diameter 1 cm)

5. Four pieces of wood for supporting the base plate.

6. Two hose clamps

7. Some hose

8. A Gauge

9. A vacuum pump (not shown)

Step 2: Prepare the Base Plate

Drill two holes in the base plate (diameter 1 cm). One is for the suction line, the other one is for the pressure gauge. If your pressure gauge is located on the vacuum pump, you will only need to drill 1 hole.

Glue the four supports to the wood. In the picture I have used 1 large en 2 short ones instead.

Step 3: Rig Up the Hoses

Fit the Aluminum pipes into the holes. If you need a small hammer to get them in, you’ll probably have an air-tight fit. If not, seal the edges with some glue. If your base plate is fairly thin, the pipes will probably not give a good air-tight fit.

Leave the pipes sticking out a bit, otherwise any liquid spoiled will be immediately sucked in by the pump.

Fit the hoses to the Aluminum pipes (one line to the pump, the other line to the pressure gauge unless your gauge is located on the vacuum pump). Use the hose clamps to rig-up the suction line and the gauge line.

Step 4: Finalise and Start-up

I have used a (perforated) rubber anti-slip foil as a gasket. It also prevents my food container from slipping. Other options are the inner tyre of a child’s bicycle or silicone rubber. 

Place the glass chamber on the gasket and when you start the pump, you might need to push the glass chamber gently down until the gasket starts compressing.

Step 5: Discussion

Vacuum infusion relies on a combination of capillary pressure and osmotic pressure. It can be done with any liquid or type of food, but the following factors play an important role:

* The vacuum pressure.
* Porosity of the food
* The size of the blocks (small chunks will have a relative large surface).
* Time 
* The composition of the liquid.
* Cell structure / texture of the food.
* The viscosity of the liquid. Hence the temperature is of influence as well.
* Surface tension.


This application is intended to infuse fruit with a water-sugar solution and to use it in ice cream. The infused solution will partially act as a kind of anti-freeze resulting in fairly soft chunks of fresh fruit at low temperatures (freeze point depression).
The remaininig solution, which contains some of the fruit flavors, can be re-used as sweetner in the ice cream mix provided the mix is corrected for this additional water (reduce the amount of milk and increase the amount of cream).

Step 6: Results

under construction (I'm currently working on some recipes. More to come soon).

Update 25th April 2010
Started with apple. Made batches and just froze them without making the ice cream (and tasted them once they were frozen).
I varied with: block size, sugar concentration, vacuum pressure, infusion time and infusion temperature.
Expect to post my first recipe this month...Sugar Infused Apple-Cinnamom Ice Cream.

Here it is:
www.instructables.com/id/Sugar-infused-Apple-Cinnamon-ice-cream/

Comments

[charmneo]

Thank u 4 making this instructable easier to understand.
Q.how much of vacuum pressure was applied?
is their a determined extreme limits for vacuum pressure?

[bertus52x11]

The vacuum pressure was between 0,5 and 0,7 Bara.
I guess the extreem limit is determined by your pump (0 bara if you have a really good pump).

[CrLz]

Interesting food tech!

Did your ice cream idea work well?

[bertus52x11]

Apple actually works quite well. When infused and frozen, the chunks are slightly brittle (not icy) and when they burst open a you can definitely  taste apple (even though part of the apple has been filled with the sugar solution and part of the spent solution tastes like apple).
Infused apple in an apple ice cream does not provide a nice contrast. However, cinnamon does!

[bertus52x11]

Alcohol definitly works, but the sugar solution is a bit tricky.
So far I have just frozen chunks of infused fruit to see what works best (saves eating a batch of ice cream each time!). Once I get it right I will start mixing it with ice cream. 

[glorybe]

       Unfortunately alcohol will be lifted by a vacuum really quickly. Anything containing water will not have any water content at all if you approach 14.7 lbs. per square inch. Many oils present in fruits will also vanish.  What is needed is to tell people to pull just a bit of vacuum so they don't ruin their food.

[bertus52x11]

 All true.

[kumiko]

Could you describe the taste of the apple after being infused with other liquids?

[bertus52x11]

The easy answer is: depends on the infusion fluid! You can create whatever exotic combination you want. However, fruits with a low porosity will have in general a relatively high water content so that the taste of the infused liquid is "dilluted". The infused liquid should have a strong taste.

The picture you see is just plain lemonade although it looks like Kerosine! It wasn't great (not strong enough), but then again it was just for demonstration purposes.

For my specific  application (chunks of fresh fruit in ice cream), I aim at having no taste difference whatsoever.

The theory is: untreated chunks of fruit become ice cubes in ice cream (due to the high water content). By infusing them with a liquid that is close to the taste of the fruit (a sugar solution), but remains more or less liquid al low temperatures, this might be avoided (freeze point depression).

In addition, you can boost the process by infusing a sucrose solution that has a much higher sugar content than the fruit (hypertonic solution). Now osmotic pressure will take part as well.

What the ideal mix is, I do not know… I have just built the rig a week ago to find out.

Try searching Google on the following words: osmotic dehydration and vacuum impregnation.

[glaporte]

 They use a very sugary pear juice mix when they can fruits as pear juice has a very neutral taste. Once you get the "anti-freeze" properties of your mix right the pear juice will allow the fruit to carry their own flavors through when in the ice cream.

[bertus52x11]

You're definitely not new to this subject, are you?

[big al 1048]

    - O.K., now I'm very confused, adding all the comments together, you can 
infuse flavor by either drawing a vacuum, or by pressurizing ?

   - I can't quite get my head around this, so  is this a job for Alton Brown or Mythbusters

   - This probably   should be listed separately as a question, but please treat this as seriously as the question was ask'd
                                                                             Big Al              

[bertus52x11]

Vacuum! You simply can't choose whatever is most convenient to you as suggested below. 

You specifically mention "flavor". Is marinating your main goal?
Apparently, a positive pressure seems to work for marinating. Seems logical, but I do not have the experience with that. Ask OleBally (but not here!).

If you want to infuse a liquid in the pore space of a delicate structure (combined with substituting part of the fluids in the matrix), then vacuum infusion is recommended. 

PS. Who is Alton Brown BTW?

[Ole bally]

No worries ! It seems that the pressure expels the air from the meat or fruit or whatever and replaces it with the marinade liquid much in the same way the 'fossils' are made I suppose!

[paintphone]

 Ive been looking for a way to make a small vacuum table to infuse fruit freshly grown from the garden. great idea! By chance what number on the gauge do you vacuum to ?

[bertus52x11]

 Between 0,5 and 0,8 Bara.

[Ole bally]

If you don't have the materials for this, use a 'pressure cooker' . drill a hole in the lid the same size as is required for a 'tubeless valve' for a car wheel. Take a new tubeless valve and fit it so that the 'air' can be pumped into the pot when the lids on! Put yr meat or whatever you want infused or marinaded into the pot, add the liquid, put the lid on and pump NO MORE than 10lbs of pressure into the pot! Leave for about 10 minutes for perfectly marinaded meat throughout! Release the pressure the normal way and there you have it! Presure cooker and marinader in one! enjoy!

[bertus52x11]

So you apply a positive pressure instead?

[Ole bally]

Clearly ! :)

[bertus52x11]

 The point I tried to make is that applying a positive pressure (compression) is quite different!