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Source of Ice for Ice Cream
Name: Isabel
Status: student
Grade: 6-8
Country: Australia
Date: Fall 2012
Question:
I watched a show on TV about how they made ice cream before refrigeration. They added salt to the ice to reduce temperature. Where did they get the ice from in the first place if it was not winter?
Replies:
Do not confuse an “open” and a “closed” system. The “salted water” comes from whatever source ice and salt come from whatever source that the ice is derived. It is not limited to the origin of the initial source of the frozen water.
Vince Calder
Isabel,
Great question! It seems hard to believe now but, before the refrigerator was invented, there was a huge trade in ice to keep things cool. Some was taken in the winter when it was freezing outside and stored in ice houses. These were insulated buildings that ice would sit in and slowly melt - if you built the building well and put a large volume of ice in it would still have some ice left at the end of the summer. Imagine what a treat it would be to have a cold drink or ice cream when it was hot outside! Some ice was also shipped, in huge blocks, from the arctic where there is normally ice all year. Ice was a very valuable commodity in those days.
Best wishes,
Tom Collins
Isabel,
Prior to refrigeration, ice would be harvested from frozen rivers, ponds, or lakes. They would then be stored in dark, insulated warehouses or caves. If the ice was packed together enough, only the outer shell would melt (that is where it is warmest), leaving the inner core still intact, and enough of this ice could last into summer.
Greg (Roberto Gregorius)
Canisius College
Isabel
In the old days, in northerly latitudes, before refrigeration,
Folks would build ice houses with really thick planks to insulate against the heat, and some built cellars to keep away from the heat.
Then during Winter they would go to the river and saw out ice blocks and store them in these “ice houses.”
They would sprinkle sawdust between the blocks of ice and over the top to help insulate them from the heat even more.
Then they would draw on the ice they stored away during the warmer months as they needed during the warmer months.
But mostly, folks would just do without.
Going back further, Columbus’ search for the spice islands was stimulated by a lack of refrigeration for meat.
The more pepper you added to the meat you were eating, the less you could smell the rotting flesh.
Other techniques such as drying (smoking) and salting the meat down were also used.
This created a high demand for spices which attracted the attention of the European monarchs who financed Columbus’ search for an easier/shorter route to the spice islands.
Sincere regards,
Mike Stewart
In the 1800's in the US and Europe, Ice blocks were cut from frozen
waterways and shipped south. The ice blocks were stored in insulated
icehouses which allowed people to have iceboxes (precursor to
refrigerators).
Even before the 'ice industry', there were chemical methods (think of
those instant cold packs). If you dissolve certain salts in water, it
will get cold enough to freeze pure water. Put the pure water in
contact with the cold-pack (salt water), then mix that ice with more
salt (NaCl or more saltpeter), and you can get cold enough to make ice
cream. These chemical methods have been used for centuries, most
notably in India.
Hope this helps,
Burr Zimmerman
Isabel,
Without the aid of refrigeration, it was indeed challenging to acquire
ice outside of the winter. During non-winter months, ice from the
winter was stored in large, heavily insulated buildings called 'ice
houses'. The ice would then be transported in well-insulated
containers to local homes and businesses for storage in small ice
boxes, where they would be used until they melted.
As you can imagine, this was a very expensive procedure! Most people
did not have access to ice outside of the winter until the advent of
refrigeration.
Shimon Unterman
During the winter they would go to frozen lakes, saw out large blocks of ice and transport them to a low ceilinged building with thick log walls and roof. They would place the ice blocks in this "icehouse" and fill in the spaces between the blocks with sawdust. Amazingly, in many parts of North America, some ice would last until the next winter because the thick walls and sawdust were excellent insulators.
I have also heard of the Incas, I believe, who sent slaves and runners to the high peaks of the Andes to collect and transport ice during the summer. Think of how luck the last runner in the chain was compared to the first one.
Hope this helps.
Robert Avakian
Hi Isabel H.,
Long ago, on our farm, ice chunks were harvested from the pond in Winter and stored underground. That "ice cellar" was lined with hay bales for insulation from the Summer heat. The ice was used until it was melted. For a cool Summer, the ice would last through August. For a hot Summer, late June.
Once the ice was melted, they did without ice cream.
Thanks for making me remember how good it is to have refrigeration!
Peter E. Hughes, Ph.D. Milford, NH
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