Hot Debate: Keeping Food Cold on Shabbos
For nearly a century, as long as electronic cold-storage for home use has been around, refrigerator use on Shabbos and Yom Tov has been a topic of intense discussion by halachic authorities. Originally, the debate centered on how operating the refrigerator door affects the thermostat, compressor, motor—and as refrigerator mechanics advanced, timed defrost, inverter, condenser and evaporator fan and other apparatus—and the permissibility of engaging these electronic components.
Modern refrigerators with computer power are much more complex and continue getting “smarter”: Opening or closing the fridge may engage door sensors, alarms or even cameras, activate sensitive monitoring of temperature (and the weight of food on the shelves!), trigger built-in LED lighting modules and more.
There was no halachic consensus back then, and there is none now. So how do we access our cold food and drink on Shabbos?
Any action in fridge operation that directly activates the motor or another automatic component is assur (forbidden), but if the activity of the fridge mechanism is somewhat delayed, it has been deemed permissible by many mainstream poskim.*
As refrigerators have introduced new computerized functions that also work independently, the various ways to circumvent them on Shabbos have changed accordingly.
An old-style, purely mechanical fridge and freezer which is thermostat-controlled needs its light deactivated (preferably the switch, but even the bulb itself) before Shabbos. Opening and closing the mechanical fridge hence would only have an indirect effect (according to mainstream opinion) on the thermostat, compressor, motor and fan.
However, many modern refrigerators with electronic circuit boards (similar to a computer) have a door switch that affects the defrost settings and/or other intricate functions. The door switch on any fridge and freezer model of the last decade or so must therefore be taped up or otherwise deactivated before Shabbos. A tight seal is important, because if the switch is able to move even slightly, though perhaps not enough to engage the lights, it may still directly affect other automatic functions. (A “ShabbosSwitch Slider” is a small plastic gadget that is secured next to the refrigerator tripper switch that needs only to be slid into place to secure the switch before Shabbos. It is recommended to draw back the slider—or strip a taped-up switch—after Shabbos, as extended deactivation can ruin the operation of the fridge long-term.)
As the refrigerator becomes more high-tech, it may introduce more issues with operation on Shabbos: A heavily calibrated signal system can count door openings, register temperature to the tenth degree, deactivate the evaporator fan (which circulates cold air; in some models, there is one only in the freezer that affects all air flow) and trigger all sorts of digital displays, alarms and lights. This type of model might also have a (hidden) sensor in the door instead of—or in addition to—the integrated switch. A magnetic door sensor would have to be disabled before Shabbos with a counter-magnet or other deactivator (technicians can sometimes move these sensors to another part of the fridge so they are not activated directly by door function).
A lot of successive fridge-door openings may still have an effect on the thermostat, compressor, motor fan, defrost and other electronic components of the computerized refrigerator even when the switches and sensors are deactivated. (The most serious of these involve an automatic defrost system that uses thermal coils; activating glowing hot wires directly is an issur d’oraisa—a Torah prohibition, and it may be problematic to affect such a system even semi-directly.) Some authorities therefore recommend only refrigerators that can have the whole circuit system deactivated for Shabbos. To take these issues into account it is suggested to open the refrigerator door while the motor is running, or with a shinui (modification) to normal use when the motor is not engaged in combination with switch and/or sensor deactivation.
However, there are contemporary poskim who permit usage of a deactivated fridge even in this case. They state that the unobserved data recorded by the fridge circuit board (computer) due to temperature change is not a clear violation of boneh (building) or mav’ir (lighting a fire), the usual issues with using electricity on Shabbos, since there is only a small amount of added current with each signal. (Another concern with using electronics is k’sivah—writing—but this is also not presented by refrigerator circuit boards when the display is disabled.) Since this action is in the category of issur d’Rabbanan (forbidden by Rabbinic decree) it is combined with other factors to result in a heter.**
New technologies have been developed by religious Jewish engineers that can circumvent even these indirect effects of fridge-door operation. “If technology offers solutions to halachic issues it has created,” their halachic proponents say, “it is incumbent upon us to utilize them.” These systems can act as a switch to turn refrigerator circuits on and off every few minutes, notifying the user when the fridge is “off” and can be opened. It is recommended to use them when available.
Some refrigerators have a Shabbos mode function, an integrated circuit board equipped with the ability to override computer function. The consumer should be aware that there are some fridge models which ostensibly include a “Shabbos mode” status but lack Rabbinic oversight. In addition, Shabbos mode operation generally does not suffice for those that rule that even initial electronic signaling poses an issue on Shabbos; most of these computer chips neutralize the temperature-controlled functions of the fridge and adjust them automatically, but do not evade the original impulses.
Editor’s Note: Zman Technologies, a US based company, has developed a timer-like device for consumer installation with an indicator that allows the user to open and close the fridge without any electronic operation.
*Some authorities permit opening the door of a mechanical fridge only when the motor is running to avoid the possibility of a rush of warm air activating it right when it is opened. They consider all electrical function caused by door operation assur and therefore rule even more stringently for a non-mechanical fridge because of all the additional functions activated even while the motor runs: automatic defrost, inverters, electronic signals, and more.
** Some of these additional sevaros (theories) supporting leniency are: The non-immediate aspect of operating the fridge is deemed grama (indirect action), a common halachic designation where there is no clear cause/effect operation initiated by the user. Some halachic authors claim it as a grama d’grama (even more indirect effect). In addition, without sensor or switch, the electronics engaged when opening the door are a halachic safek (doubt) on a d’Rabbanan—the user does not know which particular door-opening operation will have the unintentional cumulative effect on the system, even though it is inevitable (called safek psik reisha). They also cite the concept of koach kocho (human action that spurs further action [that effectuates a prohibited act])—perhaps the warm air that prompts the computer signals is not actually considered human intervention.