From: "Wilhelm, Monique" <mwilhelm**At_Symbol_Here**UMFLINT.EDU>
Subject: Re: [DCHAS-L] Liquid Nitrogen Ice Cream
Date: Sat, 24 Sep 2016 22:47:51 +0000
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: 1109037139E1524980CF9CBEB2476618010ACE5C48**At_Symbol_Here**UMF-EX10EMB2.umflint.edu
In-Reply-To


I have never made liquid nitrogen.  I do make dry ice ice cream about 4 times a year.  Kids love the carbonation.  My daughter says it is like an automatic root beer float (even though we don’t make it root beer flavored).  Here is the procedure I keep for our Demo Squad (of course, with me, they are required to fill out a risk assessment form before the demo):

 

Carbonated Ice Cream

Materials



What To Do

 

  1. Demo day set up

A.    Crush the dry ice into little pieces.

1.      Place in paper bag and smash with a mallet

B.     Mix all other ingredients in a large bowl

  1. For the demo/activity

A.    Shake the dry ice into the ice cream, a little at a time

1.      Mixing in between additions

B.     When adding more dry ice, it will start to harden, and get more difficult to mix.

C.    Continue adding dry ice until the ice cream reaches the desired consistency.

D.    Remove stray chunks of dry ice with a small fork, or spoon

1.      Once all dry ice been removed, enjoy

3.      Post Demo Clean Up

A.    Clean the bowls and spoons

B.     Put dry ice away in a -90oC freezer, or let it sublimate in a fume hood

 

What’s Happening

Dry Ice is frozen carbon dioxide, which is part of the earth’s atmosphere. The temperature of dry ice is -78.5oC, so it can help things freeze and be kept frozen. When breaking up the chunks of dry ice at normal temperature of the atmosphere, the ice will turn from a solid to a gas through sublimation. When the dry ice is added to the ice cream mixture, the mixture will start to thicken up, a little at a time, and there will be some CO2 bubbles forming. When you get to the consistency that you want, stop adding the dry ice, or it will become harder to stir, and hard to scoop. When done at the consistency you want, scoop out the dry ice pieces that didn’t break up, so you don’t eat any (this could lead to asphyxiation or cause other health affects). Then make a bowl or a cup with whatever toppings you want.  The tangy flavor is from the CO2 that bubbled through the liquid ice cream mixture.

 

Hazards

Dry Ice is a cryogenic material which has a boiling temperature of less than -73oC. It can cause tissue damage and asphyxiation due to oxygen displacement. It also poses as a fire hazard if the oxygen is condensed out of the atmosphere. Dry ice ice cream is simple to freeze so insulated gloves are appropriate.  Try to stand back while breaking the chunks or handling or have a fan available to keep air circulating so you don’t breathe in large amounts of the CO2.

 

 

From: ACS Division of Chemical Health and Safety [mailto:DCHAS-L**At_Symbol_Here**PRINCETON.EDU] On Behalf Of Debbie M. Decker
Sent: Friday, September 23, 2016 12:08 PM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] Liquid Nitrogen Ice Cream

 

I wonder - could you do similar with crushed dry ice?  Sounds like a weekend project to me …..

 

Thanks for the recipe, David.  In the absence of LN2, that’d freeze up nicely in an ice cream freezer, too.

 

Debbie M. Decker, CCHO, ACS Fellow

Immediate Past Chair, Division of Chemical Health and Safety

University of California, Davis

(530)754-7964

(530)304-6728

dmdecker**At_Symbol_Here**ucdavis.edu

 

Birkett's hypothesis: "Any chemical reaction

that proceeds smoothly under normal conditions,

can proceed violently in the presence of an idiot."

 

 

From: ACS Division of Chemical Health and Safety [mailto:DCHAS-L**At_Symbol_Here**PRINCETON.EDU] On Behalf Of DAVID Katz
Sent: Friday, September 23, 2016 7:04 AM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] Liquid Nitrogen Ice Cream

 

Hi Melissa,

 

I have made liquid nitrogen ice cream for years with no problems. Here is the link to my procedure http://www.chymist.com/Liquid%20N2%20ice%20cream.pdf

 

Remember, you are working with a cryogenic fluid.  Safety procedures must be followed as well a food safety procedures..

 

At the ACS meeting in Boston, the RSC hired the Wiches of Boston to make liquid nitrogen ice cream at their booth in the exposition. They used my recipe.  http://www.chymist.com/Liquid%20N2%20ice%20cream.pdf

 

Best regards,

 

David 

_________________________________________________________________________
 
  David A. Katz             
  Chemist, Educator, Expert Demonstrator, Science Communicator, and  Consultant
  Programs and workshops for teachers, schools, museums, and the public
  133 N. Desert Stream Dr. * Tucson, AZ 85745-2277 *  USA
  voice/fax: (520) 624-2207 * email: dakatz45**At_Symbol_Here**msn.com
           Visit my web site:  http://www.chymist.com
_________________________________________________________________________

 

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