liquid nitrogen for Food Tech

[Deleted member 32724]

I have experience with this and would strongly recommend that you do not add either liquid nitrogen or dry ice directly to the ice cream mixture.
When I was trialling it with dry ice, there were small amounts still not sublimed within the hardened ice cream and imagine something similar could potentially happen with liquid nitrogen. This makes sense because as the ice cream hardens it acts as an insulator.

Using dry ice or liquid nitrogen to cool the mixture externally is fine as you eliminate any issue of someone accidentally biting into dry ice or liquid nitrogen.

I would never add those chemicals directly unless I had some sort of proper training from someone more experienced.

 

[Dino Girl]

My previous HOD bought in two CO2 canisters exactly for this.

I have heard about tech's using an old soda stream and CO2 canisters sprayed into a fabric bag to get enough dry ice for a cloud chamber.

 

[Artemis]

We buy LN2 once a year for a series of demonstrations in chemistry, mainly dipping flowers and rubber tubing into a dewar of LN2 and watching them flash freeze. It always culminates in a lesson where we make LN2 ice cream for the class.
There are a quite a few considerations before you rush into this lesson.
We made sure we had a separate RA specifically for the LN2.
Make sure whoever you get it from is licensed to sell LN2 for Human consumption. We used to get it from BOC but they now specifically ask if you are making ice cream and will refuse to sell it if you are.
We now get ours from Mansfield Cryogenics - they are licensed to sell LN2 for use in human consumption, they supply a lot of the fancy restaurants etc. However they did insist on a site visit to perform their own RA of where we were storing and using it before selling it to us. No bad thing.
As you can guess this is in no way an overnight undertaking - some thought, training and proper RA's should go into this before you get close to starting it.
Its not however impossible and the students and staff here really enjoy the lessons - and a lesson that ends in a small sample of ice cream is always good!!

 

[RadioChemist]

I used to handle liquid nitrogen regularly when working with NMR (magnet cooling)

You will need specialist kit to store and move it, I'm not sure you can take it in a lift (accompanied or not) these days, we ended up with piping running up the outside of the building so we could fill our storage vats directly.

You might find BOC is your only source and they may offer up to the date advice, even hire out the gear you need for storage transportation.

Hopefully the cookery room is on the ground floor.

If you are looking for a good excuse to tell the Cookery team to think again, the amount they require may well be below the minimum that BOC will deliver

 

[PartingtonJ]

Hi All

Does anyone buy in liquid nitrogen for food tech to make ice cream?

I have never done this before and I have no formal training when it comes to handling liquid nitrogen. They want me to buy some in that they can use over the course of a week, which means safe storage in between usage. We are a very small school and have limited storage space, there's no where safe food tech could store it which would mean storing it in our chemical store and then transporting it somehow over to food tech as needed.

Does anyone have any advice before I call CLEAPSS?

Thanks

Don't know where in the country you are but the chemistry department at the University of Manchester will give liquid nitrogen to schools provided you attend a handling course and have a suitable dewer.

 

[Paul]

I have experience with this and would strongly recommend that you do not add either liquid nitrogen or dry ice directly to the ice cream mixture.
When I was trialling it with dry ice, there were small amounts still not sublimed within the hardened ice cream and imagine something similar could potentially happen with liquid nitrogen. This makes sense because as the ice cream hardens it acts as an insulator.

Using dry ice or liquid nitrogen to cool the mixture externally is fine as you eliminate any issue of someone accidentally biting into dry ice or liquid nitrogen.

I would never add those chemicals directly unless I had some sort of proper training from someone more experienced.

there were cases in cocktail with super cold drinks made with liquid nitrogen.

Nitrogen cocktail destroyed birthday woman's stomach

How a cocktail containing liquid nitrogen turned an 18th birthday into a life-changing nightmare.

www.bbc.co.uk

 

[TechNewham]

I used to handle liquid nitrogen regularly when working with NMR (magnet cooling)

You will need specialist kit to store and move it, I'm not sure you can take it in a lift (accompanied or not) these days, we ended up with piping running up the outside of the building so we could fill our storage vats directly.

You might find BOC is your only source and they may offer up to the date advice, even hire out the gear you need for storage transportation.

Hopefully the cookery room is on the ground floor.

If you are looking for a good excuse to tell the Cookery team to think again, the amount they require may well be below the minimum that BOC will deliver

I remember the wait for Monday morning lectures at UCL would concide with the weekly liquid nitrogen delivery. A white truck would reverse through us and a pipe would be pulled out and plugged into the building. Moments later the entire yard would vanish in an impenetrable white haze that seemed to last for a minute or two. Rather refreshing in the summer, but not appreciated in the winter. No-one collapsed from lack of air, but as the year went on, more and more of us moved to other areas as the delivery approached.

 

[Kasfarer]

Sounds like another hair brained, not thought through teachers idea that they have found while idly browsing the internet to me.
Ask to see their risk assessment (or if it was me I would just say no).

Ah, you've met my teachers, then!

Coincidentally, one of ours suggested liquid nitrogen recently. It was his 'back-up' idea after we said no to taping the Whoosh bottles together.

 

[Lozzie-Lou]

I have experience with this and would strongly recommend that you do not add either liquid nitrogen or dry ice directly to the ice cream mixture.
When I was trialling it with dry ice, there were small amounts still not sublimed within the hardened ice cream and imagine something similar could potentially happen with liquid nitrogen. This makes sense because as the ice cream hardens it acts as an insulator.

Using dry ice or liquid nitrogen to cool the mixture externally is fine as you eliminate any issue of someone accidentally biting into dry ice or liquid nitrogen.

I would never add those chemicals directly unless I had some sort of proper training from someone more experienced.

Actually thinking about it I think they had to sit the ingredients in the zip lock bag into a box of dry ice (as in me putting them in there with some safety gloves). It was only Yazoo milkshake and a bit of salt to speed up the freezing...like I said it was a few years ago now, but whatever happened it worked well! ^^^Because yeah, directly adding dry ice does not sound right...

 

[Kasfarer]

Actually thinking about it I think they had to sit the ingredients in the zip lock bag into a box of dry ice (as in me putting them in there with some safety gloves). It was only Yazoo milkshake and a bit of salt to speed up the freezing...like I said it was a few years ago now, but whatever happened it worked well! ^^^Because yeah, directly adding dry ice does not sound right...

Our science academy made ice-cream with standard ice and salt in a zip-lock bag. I wasn't around for it, but apparently it worked a treat. I think the method is on CLEAPSS.

 

[Phystech]

I have experience with this and would strongly recommend that you do not add either liquid nitrogen or dry ice directly to the ice cream mixture.
When I was trialling it with dry ice, there were small amounts still not sublimed within the hardened ice cream and imagine something similar could potentially happen with liquid nitrogen. This makes sense because as the ice cream hardens it acts as an insulator.

Using dry ice or liquid nitrogen to cool the mixture externally is fine as you eliminate any issue of someone accidentally biting into dry ice or liquid nitrogen.

I would never add those chemicals directly unless I had some sort of proper training from someone more experienced.

Just keep stirring.

 

[Deleted member 32724]

Just keep stirring.

I did (with the CO2), but it's hard to stir a solid lump and then to also guarantee all the dry ice has sublimed? Too risky in my view.
Haven't tried with liquid nitrogen though.

 

[LivLabTech]

Our science academy made ice-cream with standard ice and salt in a zip-lock bag. I wasn't around for it, but apparently it worked a treat. I think the method is on CLEAPSS.

RSC making ice cream

 

[Techitude]

RSC making ice cream

I highly recommend double bagging the cream/milk when the kids do it as this prevent the salty water getting into the ice cream if the bag isnt fully sealed or comes open slightly. The bags burst more often that they should when the kids are shaking them.