Where there is smoke in a bowl, there is better ice cream

The recipe

More often than not, I am confused – unable to make sense of even the most basic things. Stuck in a contemplative paralysis.

With age, I have learned that I should not fear confusion. No. For confusion is the fertile soil that nurtures the seeds of curiosity. Curiosity drives learning. Learning creates knowledge and from knowledge we gain experience. That is, if you decide to do something with your knowledge.

Dry ice magic
Dry ice magic

For a few weeks now, I have been reading about the use of science in the kitchen. Given that I have no formal training in chemistry, reading about atoms, positively or negatively charged electrons, denatured proteins or surface-to-volume ratios, the onset of yet another state of contemplative paralysis was to be expected.

Someone once told me, “[…] if you do not know what to do, just do something”.

So I went shopping. Bought a nice tub of organic ice cream and found a quiet place to enjoy it. It was good, better than mine, but contained some rather large ice crystals, which gave it a grainy mouth feel. Aha!

I had recently read somewhere about the formation of ice particles in ice cream and how to avoid it.

Ice cream consists of only three basic elements: ice crystals made of water, concentrated cream and air. When these three elements are in balance, the ice cream is good: creamy, smooth, firm and almost chewy.

To achieve a really good ice cream, the custard mixture must be cooked (above 76°C) to denature the whey proteins in the milk and cream, frozen as quickly as possible whilst being stirred (to incorporate air and the prevent the formation of large ice crystals that eventually lump together and cause a grainy texture), and once done, hardened as quickly as possible (again to prevent large ice crystals).

Hocus pocus
Hocus pocus

The biggest challenge for ice cream makers at home, is the time it takes to freeze and harden our ice creams. Using an ice cream machine designed for home use, helps with the churning but often does not reach low enough temperatures quickly enough, and our freezers are not capable of near instant freezing. Thus, commercial ice cream seems to always be smoother and firmer.

My chemistry sources suggested using either dry ice (carbon dioxide in solid form) or liquid nitrogen (nitrogen in a liquid state at low temperature) to achieve the low temperatures required for smooth ice creams.

It took me quite a few days to locate the local supplier of dry ice, because I looked in all the wrong places. So, I’ll spare you the details of my quest that took me all the way to a veterinary practice that uses dry ice to preserve bovine semen and blood samples. Just go to Afrox. They sell the stuff by the kilogram, so take a plastic cool box along.

A few words of caution though: dry ice is cold. Very, very cold.

Carbon dioxide changes from a gas into its solid form at -78.5°C. Thus, do not touch dry ice, unless you want frostbite. Wear protective gloves and goggles. No ice cream, however smooth, firm and chewy is worth the loss of an eye.

Voila!
Voila!

When dry ice “melts”, it turns from its solid form into a gas, without first becoming a liquid (as is the case when normal ice melts). Thus, dry ice should not be kept in an airtight container – such as a glass or plastic bottle with a seal or a tight cap – as the gas buildup will cause the container to explode. The ordinary cooler box is fine for keeping dry ice, as it is not airtight.

Finally, use and expose dry ice only in a well-ventilated place, to prevent hypercapnia caused by breathing in too much carbon dioxide.

Off course, supervise your children when using dry ice.

Dangers taken care off, using dry ice to make ice cream is loads of fun. Seriously.

Ice cream
Ice cream

I picked up my dry ice from Afrox late Friday afternoon (they are closed on Saturdays). It was too late to start with my experiments, so I spent Friday evening getting my recipes ready. I had already decided to experiment with retro-flavours, and to make both custard-based ice cream and sorbets. I had already made a ginger beer reduction a few days before, and bought some liquorice and rhubarb. These would be my base flavours to go with eggs, milk and cream, water and sugar.

I spent most of Saturday wearing safety goggles and red, latex-covered gloves, spooning ladles of dry ice into my various base mixtures.

In an instant, the mixing bowl became a druid’s cauldron. Smoke poured out of the mixtures, crawled over the table and cascaded down onto the floor.

I felt like Getafix and could pretend that I was stirring the potion that made Obelix and all the Gauls invincible against the persistent onslaught of the mighty Romans.

Sorbet
Sorbet

Later the afternoon a crowd of children gathered as I once more stoked the cauldron. As the mixture of milk, cream, sugar and vanilla bubbled and rose to the occasion and over the brim and onto the grass, I felt like Harry Potter. This was the most fun I had in a long time.

Was the ice cream any good?

I saw four good mothers secretly gather in a room under cover of darkness with deep soupspoons and the last bowl of my ice cream. And there, in unison, they swore each other to secrecy. Not to tell the children about the true fate of their ice cream.

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