Vacuum Pot Brewing Temperature

by Jack Denver

The ancient Greeks favored using logic over actual experiments. Logic told them that heavier objects fall faster than lighter objects. People believed this for 2000 years, until Galileo climbed the tower of Pisa and proved through experimentation that this was just plain wrong.

Logic tells you that vac pots heat the water beyond 100C. An experiment (a thermometer) would prove that you too are just plain wrong. The water in the upper (brewing) chamber of a vac pot is indeed in the ideal range of temperature. Despite the vigorous bubbling that you see, the water is NOT boiling in the upper vessel. The water in the lower vessel is boiling, of course. However, by the time it reaches the upper vessel, it cools to 95C. or so due to heat loss from contact with the cooler grounds and glass. The upper vessel is a good distance from the heat source and is relatively cool. It NEVER reaches boiling in normal brewing operation. Many people have measured this temp. and it is always below boiling.

This accounts for the wonderful results achieved by vacuum brewing vs. most drip methods... the brewing temperature remains ideal throughout the entire brewing time. The grounds are fully saturated and agitated, as in a French press. Electric drip machines are usually below ideal temp and often do not wet the grounds fully. Manual drip does not control the temp. accurately either... the water may start out too hot and cool below ideal by the end of the infusion. Most vacuum brewers use a "glass filter" which imparts no taste of its own and does not remove oils, as paper drip filters do. The end result is a brew with the strength and flavor of French press, but the clarity of drip. Its also fun to watch the water go up and down.

Why don't you try it yourself?

Jack Denver