Coffee Machine

Coffee machines have two main elements: a tank to heat the water, and bins to hold such items as coffee powder, chocolate, etc. In some machines, the coffee is a liquid concentrate. A small amount of concentrate can be diluted in a pitcher to make coffee.

 The machine is connected to a source of regular tap water, which is heated in the tank by an electric heating element. When a button is pressed, the water and the coffee concentrate flow into the receiving vessel, either a pitcher or a glass. The machine is electronically controlled to provide the proper ratio of water and coffee or other additive.

 What problems are there in using such a machine on Shabbat?

 (1) Cooking the water in the tank. (2) Cooking the coffee by putting it into the hot water. (3) Various electrical operations, including turning on the heating element.

 The solution:

 (1) The hot water tank operates as an "Overflow Water Heater." Cold water enters the machine on a fixed cycle that does not depend on any human actions. Thus, nobody has any influence over the heating or cooking of the water, and excess hot water is discarded into the sewage.

(2) The Shabbat equipment is adjusted for the size of a pitcher as typically used in hotels, since these are the most common institutions which need to make coffee on Shabbat. The waiter puts the pitcher under the spout and opens a mechanical valve. After a short pause (depending on what point the machine is in its regular cycle), hot water will fill the pitcher instead of being sent out to the waste disposal pipes by the overflow system. That is, the mechanical valve is simply a two-way selector between the outlet to the pitcher and the waste overflow.

(3) Opening the mechanical valve also dispenses the proper amount of coffee, in a completely mechanical way, without any electrical activity.

(4) The coffee enters the pitcher with the halachic status of a kli sheini – a vessel not directly heated by a flame – or, at most, pouring from a kli rishon – a directly heated vessel. There is less of a problem if the coffee has been precooked (such as with instant coffee), since the rule is that "cooked food cannot be cooked again" by reheating it.

(5) On Shabbat, all the electrical switches and buttons are disconnected. The only light is a signal that the machine has been switched to Shabbat control. During the week, the machine is returned to its normal mode of operation. The change from one mode to another is controlled by a timer or by a key that is under the responsibility of the kashrut supervisor.

For details and clarifications, contact The Zomet Institute: