Click for ...
about    bibliography    certification    gallery    glossary    ingredients
links    products    site statistics  ▪  kosher in    k-organic    k-techno
charities   •  adverts    site-map
Compiled by Roger Shlomo Harris
Copyright © 2006-2010

Kosher Technology
Shomer Halacha, Shomer Shabbat


This page is intended to give details of some technical artifacts whose design and function permits the observance of halacha whilst simultaneously providing a benefit, e.g. heating food on Shabbat.
Also included are a few items which raise halachic questions which are not linked to Sabbath observance.
Some others, e.g. water filters, are similar to foods in that their manufacture is subject to kashrut laws. One does not expect to eat a water filter but if the filter material contained chometz then the output would be suspect. Elsewhere, I read of a brand of poisonous drain cleaner which had a Kosher L'Pesach hechsher. The intention was apparently to guarantee that it did not contain chometz and could thus be owned by Observant Jews during Pesach. Another interesting application is that of a brand of kosher, hechshered olive oil intended for Sabbath lights, nerot shel shabbat, but prohibited for consumption as food.
Thirty-nine categories of work are proscribed during Shabbat.

An illustrated display of the 39 melachot as represented by tools and equipment may be seen at list of 39 melachot
If you are an inventor, either aspiring or practising, then the contemporary problems listed on the AskMoses web-site, above, may inspire you to design a device which will permit an activity which is currently proscribed. Jews have discovered and invented some amazing things - please see my list of Jewish scientists and technologists.

Sukkah Roof Opener
Pneumatic devices, apparently similar to those which are fitted to motorcar hatchback doors, are offered by Air Power Creations (+1 718-388 0373) to open your sukkah roof on Shabbes and Yom Tov. Approved by Gedolei Rabbanim. It is not the only way to open a sukkah roof on Shabbat and Yom Tov.

Perko Hot Pots
With an integral Shabbes switch: Shabbat Mode shuts off all electrical functions except the "keep warm" function. When in Shabbat Mode, cold water may be added on Yom Tovim but not on Shabbes. Bears the hechsher of Rabbi Avraham Chaim Steinwurtzel, Brooklyn, NY, U.S.A.
Retailers please contact: +1 917-370 7057.
A selection of Kosher Shabbat lamps & gadgets is available from J. Levine's store in New York: web-site blocking
The system blocks visitor access to your web-site during the hours of Shabbes. The promoters write: "With the Shomer Shabes system your website will be active and open to search engines, but inaccessible to visitors who are located in a Shabbat or holiday time zone, protecting them from desecration of those holy days."
Zomet - Techno-Halachic Systems and Devices
The Zomet Institute was established in 1988 in Alon Shevut, Gush Etzion with the goal of addressing problems of:
a. Halacha & Technology
b. Torah & Science
c. Judaism & Modern Society

The Zomet Shabbat Amigo electric wheelchair is "halachically-authorised for use on Shabbat. Intended only for individuals whose limited mobility is dependent on a POV/scooter or automobile consistently throughout the week."

The Machine Matzah Controversy, by Rabbi Shmuel Singer
The Geek Guide to Kosher Machines
Engineering, electronics and Sabbath observance
Jewish Garage Door Opener
This video should amuse you. It plays for about 62 seconds and was made by Jewish Impact Films of Los Angeles. My thanks go to Sam S. for sending it.
KosherLamp - a controllable Shabbat lamp
Jewish Sabbath observance proscribes the switching on or off of electricity. Here is an invention which provides a halachically-compliant mains-electricity-powered light source (a moveable shutter graduated between on and off controls the light level) which may be used on Shabbat for reading and general lighting. The base and fixed body of the lamp are muktza, i.e. objects which may not be moved on Shabbat. The base has rubber feet which reduce the likelihood of movement and the shutter, which is not muktza and thus moveable on Shabbat, is mounted on a ball-bearing which permits easy movement. There is currently no means of anchoring the lamp firmly on a table or shelf. [The Halachos of Muktza by Rabbi Yisroel Bodner, Feldheim Publishers, deals comprehensively with muktza.]
Shabbat Elevator
In preparation.
Blech is a German word meaning "sheet metal." At its simplest a blech is a metal sheet, usually steel or aluminium, which is placed upon the cooking area of a gas or electric stove. The gas burners or the electric heating elements are set to a low heat and they then remain active during the hours of Shabbat. Pots placed on the blech will be kept hot. Two distinctly different types are in use: (a) plain blech consisting of a single sheet of metal, (b) a water receptacle having dimensions of 18" wide, 26" long, about 0.75" high and covered by a lid of similar width and length. [more-1, more-2 ]. Both function by transmitting heat mainly by conduction and partially by air convection.
Water Filters
K-Pure Water Filter Cartridge. Kosher for Pesach. Supervised by Rabbi Yosef Teitelbaum, Beth Din of Kolel Vayoel Moshe, 4514 15th Avenue, Brooklyn, NY, U.S.A. Tel: +1 718-851 7887.

An ingenious water filtration device which will may one day achieve kosher certification is the LifeStraw®. It is a plastic tube, about 10" long and about 1.25" in diameter and it has a nozzle at either end. It held in the hand with the lower nozzle in polluted water and the upper nozzle in the mouth; one sucks water through the device. It contains filters which are intended to remove sources of typhoid, cholera, dysentery and diarrhoea from surface water thus turning it into drinking water for people in third world countries who do not ordinarily have access to clean drinking water. [SOURCE: Matthew Green's Around The Web newsletter, no.318, 20 October 2006.]
Mobile phones
Mirs Communication, an Israeli telecomms company which is a subsidiary of Motorola, offers a mobile phone which does not include internet access, SMS text services and video and voice-mail applications in its specification. The device is aimed at the Chareidi market in Israel. [more-1,more-2,more-3]
Kosher Clock
A small digital clock with five preset alarms. During the hours of Shabbat the clock is muktza, i.e. an object which should not be touched or moved. The alarms sound for one minute each so that one need not touch the clock to switch off the alarm.
More clocks
Time Switches
These are perhaps the devices most frequently used in Observant households to switch lights and equipment on and off during the hours of Shabbat.
Refrigerator Light Switch cover
A sliding cover prevents the switch inside the refrigerator from being actuated by the refrigerator door; affects incandescent lights, LED lights, freezer defrosters.
Light Switch Covers
A protective cover which fits over a light switch to prevent inadvertent manual operation of the switch during the hours of Shabbat. [more]
Kosher Lock Kosher Lock
Carrying objects outside one's home is proscribed on Shabbat. Keys are muktza but may be "worn" as an item of clothing on Shabbat by incorporating them as links into a belt.
This door lock does not require a physical key. It incorporates a ten-digit keypad which one uses to enter a pass-number which releases the bolt. The bolt is then operated by the knob.
Electric shavers
These are muktza on Shabbat. The halachic problems relate to the method of cutting of the beard.
book: The Halachic Guide to Medical Practice on Shabbos The Halachic Guide to Medical Practice on Shabbos
Author: Rabbi Michael Chizkiyah ©2005
Publisher: Targum Press, Southfield, MI, U.S.A.
Format: Hardcover. 364 pages. About 15.8cm W x 23.5cm H
ISBN: 1-56871-359-2
Shabbat and the modern kitchen Shabbat and the modern kitchen
Author: Rabbi L.I. Halpern, [Head, Dept. of Halacha, Institute for Science and Halacha, Israel],
Translator: Rabbi Dovid Oratz [Hebrew into English],
Publisher: Gefen Publishing House Ltd., Jerusalem, Israel. © 1986,
Format: Hardcover. 206 pages. About 16cm W x 23.5cm H,
ISBN: 965-229-021-1.

A summary of the Contents page:
Section I: Modern Heat Sources and the Prohibitions of Shabbat
Section II: Automatically Heating Food on Shabbat
Section III: An Alternate System for Re-heating Food on Shabbat
Section IV: Re-heating Food for Hospital Patients
Section V: The Thermostat in Refrigeration and Heating
Section VI: Hot Water Systems