Saltpeter, known as a material for gunpowder, was used as a cooling agent for wine

Saltpeter is a mineral that was used as a material for gunpowder in Japan in the Edo period and Europe in the Middle Ages. Saltpeter has the property of `` causing an endothermic reaction when put in water '', and it was used to cool wine etc. before its use as gunpowder was discovered. The history blog The Regency Redingote explains the unknown history of such saltpeter.

Saltpetre: Regency Refrigeration |
https://regencyredingote.wordpress.com/2013/08/09/saltpetre-regency-refrigeration/

Saltpeter is a mineral that occurs naturally in private toilets and stables in arid regions. Saltpeter has been studied for a long time, and gunpowder was produced using saltpeter in Europe in the Middle Ages and in Japan in the Edo period. However, in ancient Greece and ancient Rome, saltpeter was used as a 'coolant' instead of gunpowder. Snow and ice were used in ancient Rome to chill wine, but snow and ice are not available all year round. For this reason, there is a record that saltpeter was added to water and used to cool wine. However, since saltpeter was a rare mineral at that time, saltpeter was used only for important meals.

After that, with the fall of the Roman Empire, the culture of using saltpeter as a coolant disappeared. The Regency Redingote explains why cooling using saltpeter has become obsolete, ``In Christian society,'coldness' was associated with death, and cooling food was considered to be contrary to God and the laws of nature. It may be,' he said.

In the 16th century, Dr. Marcus Antonius Zimara of the University of Padua introduced the cooling method using saltpeter as a 'new discovery', which attracted attention again in Europe. However, many doctors at the time thought that ``cooling drinks with ice or snow'' would cause paralysis, blindness, and sudden death, and many negative opinions were received about the cooling method using saltpeter. About. Some doctors who were against the use of saltpeter thought that if a bottle of wine was soaked in water mixed with saltpeter, the components of the saltpeter would permeate the glass and mix into the wine.

Giambattista della Porta, a friend of Galileo Galilei, is the most prominent scientist who has documented cooling methods using saltpeter. Della Porta's book 'Nature Magic' contains a description of a cooling agent that combines saltpeter and snow, stating that it was able to create 'a state twice as cold as snow'.

Around the 19th century, cooling methods using saltpeter began to appear in magazines. The cooling method that was widespread at that time is like this. First, prepare a wooden container with a volume of 10 to 12 gallons (about 38 to 45 liters), fill the container with 4 to 5 gallons (about 15 to 19 liters) of water, and add 5 to 7 pounds of finely crushed saltpeter. 2-3 kilograms). As a result, well water of 24 degrees will be cooled to 7 degrees after 15 minutes. Also, saltpeter could be recovered by evaporating water and could be reused.