Tag Archives: Insights from the Institute

Going Up: All About Shabbos Elevators

Going Up: All About Shabbos Elevators

By: Rabbi Mordechai Frankel

Summer 2024

Historians claim that two hundred and twenty-four slaves were needed to operate the pulleys of the elevator system in the Colosseum of Rome. Thankfully, technology has come a long way since then. Modern elevators run on electricity which has necessitated the development of a Sabbath Mode. In Sabbath Mode, an elevator cab moves continuously up and down the elevator shaft, stopping at every floor. However, as will be explained, not all Sabbath Modes are the same.

Physics 101: How Elevators Work

There are two basic types of elevators in common use today: hydraulic and traction.

Hydraulic-Type Elevators

Hydraulics make use of the principle that liquid moved with low force over a large distance can be converted to movement with high force over a short distance. Take, for instance, a simple hydraulic jack (see Fig. 1). If the piston on the right has a surface area ten times that of the piston on […]

Insights From the Institute: The Mesorah on Duck Eggs

Insights From the Institute: The Mesorah on Duck Eggs

By: Rabbi Mordechai Frankel

Summer 2023

Q:        My local farmer’s market sells duck eggs. Can I assume that they are kosher?

A:        Although the Torah lists twenty-four non-kosher species of birds, we no longer know precisely to which species the Torah is referring.[1] The Gemara provides alternative ways to ascertain whether a bird is kosher, but notes an instance in which a mistake in identification transpired.[2] For this reason, Rashi states that we do not rely on the Gemara’s criteria, and we eat only the few species of birds for which we have a mesorah (oral tradition) that attests to their kosher status.[3]

The Baal Ha’maor, one of the Rishonim, maintains that he has a tradition that all birds with wide feet and a wide beak – those more or less resembling a goose – are deemed kosher if they meet the Gemara’s criteria.[4] The Shulchan Aruch […]

The Basics of Tzaar Baalei Chayim

The Basics of Tzaar Baalei Chayim

By: Rabbi Mordechai Frankel

Spring 2021

The prohibition to gratuitously cause pain to an animal is known as tzaar baalei chayim. The Gemara presents a debate as to whether this is a Torah or a Rabbinic obligation.1 Most Rishonim pasken that it is forbidden mideoraissa,2 although some Rishonim pasken that it only prohibited midrabonon.3 The Nimukei Yosef suggests that the Torah forbids one to cause an animal significant pain, and the rabonnon extended this and forbade causing less substantial pain as well.4

There is some uncertainty as to the view of the Rambam. The Kesef Mishna states that the Rambam considers tzaar baalei chayim to be a Torah command,5 whereas the Ohr Sameach opines that the Rambam regards it to be a Rabbinic prohibition.6 The Netziv offers a unique resolution of the Rambam’s position. He suggests that the Rambam paskens that it is asur mideoraissa to cause pain to one’s own animals and asur midrabonon […]

Halachos of Pet Neutering

Halachos of Pet Neutering

By: Rabbi Mordechai Frankel

February 2021

Q: May one ask a vet to spay a pet?

A: I frequently get asked this question. People who have pets often prefer to have them neutered, as this makes the animals more docile. However, there are serious halachic issues associated with this. Poskim differentiate between whether a male or female animal is being neutered. The neutering of a male animal is known as castration, whereas neutering a female animal is called spaying.

The Torah (Vayikra 22:24) states that castrating men and male animals is forbidden. This prohibition is known as sirus.1 It is also forbidden to remove a woman and female animal’s reproductive organs. The Gr”a is of the opinion that this is a Torah prohibition. The Taz, however, feels that causing a female animal to become infertile is permitted. According to the Taz, the reason it is forbidden to remove a female animal’s reproductive organs is solely due […]

Mezuzah Guidelines for a Walk-in Closet

Mezuzah Guidelines for a Walk-in Closet

By: Rabbi Mordechai Frankel

Kashrus Kurrents Winter 2019

Q: Does a walk-in closet in my house need a mezuzah?

A: Many of the doorways of the various rooms in a person’s house are required to have a mezuzah on the doorposts; however, not every doorway is halachically obligated to bear one. Whether or not a particular room needs to have a mezuzah will depend upon the location of the doorway, the intended use of the room, and other factors. A complete exposition of all relevant halachos is beyond the scope of this article. We will limit ourselves to one specific question: What are the specific measurements that a walk-in closet would need to meet in order to halachically be considered a “room”? In other words, when is a walk-in closet large enough to require a mezuzah and when is it small enough that it does not?

A large walk-in closet is halachically considered to be a room […]

Petting an Animal on Shabbos

Petting an Animal on Shabbos

By: Rabbi Mordechai Frankel

Kashrus Kurrents Spring 2018

Q: May one pet an animal on Shabbos?

A: Chazal enacted a takanah designating certain types of objects as muktzah, thereby limiting a person’s freedom to move those items on Shabbos. There are various categories of muktzah with differing degrees of limitation of movement. For example, a utensil which is generally used for an activity prohibited on Shabbos is muktzah. A naturally occurring object such a stone is also muktzah unless it has been designated before Shabbos for a specific purpose. Similarly, the Talmud states that an animal is muktzah.

In former times, it was common for children to play with young birds and listen to them sing. Tosefos suggests that a bird should not be considered to be muktzah as it can be used as a distraction for a crying child. However, Tosefos rejects this and concludes that birds are muktzah. Similarly, the Shulchan Aruch paskens that animals […]

Halacha of Erecting a Fence Around a Roof

Halacha of Erecting a Fence Around a Roof

By: Rabbi Mordechai Frankel

Kashrus Kurrents Winter 2018

Q: Under which circumstances is a person obligated to erect a fence around the roof of his house?

A: The Torah in parshas Ki-Setze states, “When you build a new house make a railing for your roof, and you shall not bring blood on your house if someone falls from there”.1 The Torah requires one to build a maakeh – a fence – around a flat roof that people walk on, so as to protect them from falling. The mitzvah applies not only to someone who builds a house but also to someone who buys, inherits or is gifted a house.2 A person who rents a house is also required to build a maakeh if the owner has not already done so.3

A maakeh has to be strong enough that a person could lean against it without falling, and it has to be ten tefachim high.[...] Read More

Eating or Cooking Meat and Fish Together

Eating or Cooking Meat and Fish Together

By: Rabbi Mordechai Frankel

Kashrus Kurrents Fall 2017

Q: What are the halachos regarding eating or cooking meat and fish together?

A: Chazal tell us that it is unhealthy to eat meat and fish together, meat which was cooked with fish, or fish which was cooked with meat.1 The Magen Avrohom suggests the possibility that people are no longer sensitive to the combination of meat and fish, and that eating this is no longer unhealthy.2 However, common practice is to avoid eating meat and fish together and not rely on the Magen Avrohom.3 Regarding this halacha, chicken has the same status as meat.4
If a person ate fish and would like to eat meat, or if he ate meat and would like to eat fish, he is required to take certain actions. The Shulchan Aruch states that he must wash his hands, but according to the Rema it is not Ashkenzai practice to do […]

Hafrashas Challah: When Challah Separation Goes A-Rye

Hafrashas Challah: When Challah Separation Goes A-Rye

By: Rabbi Mordechai Frankel

Kashrus Kurrents Summer 2017

Q: I made some dough in order to bake bread and separated challah. When I wasn’t looking, someone inadvertently took that piece of separated challah and added it back into the rest of the dough. Now that the dough and challah are all mixed together, how should I proceed?

A: Before we discuss how to proceed, let us clarify one point. The word “challah” has two meanings. It is used as the name of a bread which is braided, baked and commonly eaten at Shabbos meals. It is also used to describe a small piece of dough that was separated from a larger batch of dough in order to fulfill the halachic obligation of hafrashas challah. We are using the word “challah” in that second sense.

Let us discuss the case where challah was mixed with dough and can no longer be recognized. If the batch of dough that […]

Do Potato Chips Require Bishul Yisroel?

Do Potato Chips Require Bishul Yisroel?

By: Rabbi Mordechai Frankel

Kashrus Kurrents Fall 2016

Q: Do potato chips need to be bishul Yisroel (cooked by a Jew)?

A: The Shulchan Aruch states that there is a rabbinic obligation that food be cooked through bishul Yisroel if both of the following conditions are met: (i) The food is generally not eaten raw, and (ii) The cooked food is something that would be served at a shulchan melochim – a king’s table.1 Since we are no longer ruled by royalty, we cannot observe what is served at a king’s table. The modern-day equivalent to a king’s meal is an elegant meal, such as that served at a wedding.2  This second condition is met whether the food is served at a shulchan melochim as part of the main course or as the dessert. In either case, if the food is generally not eaten raw it needs to be bishul Yisroel.3

The Aruch Hashulchan proposes that potatoes […]

When to Recite Hatov V’Hameitiv Over Wine

When to Recite Hatov V’Hameitiv Over Wine

By: Rabbi Mordechai Frankel

Kashrus Kurrents Spring 2016

Q: When is the brocha of Hatov v’Hameitiv recited over wine?

A: Before drinking a cup of wine, one recites the brocha of Borei Pri Hagofen. Under certain circumstances, if a different wine is subsequently drunk one recites an additional blessing – the brocha of Hatov Vehameitiv.1 The brocha gives thanks to Hashem for blessing the person with a richness of wine. The Hebrew text of the brocha is   2ברוך אתה ה’ אלקינו מלך העולם הטוב והמטיב

This brocha is recited only if a number of conditions are met:

If the second wine is of lesser quality than the first wine, Hatov Vehameitiv is not recited.3 There is one exception to this rule. If the first wine is red and the second one is white (but not the other way around), Hatov Vehameitiv is recited even if the second wine is known to be of slightly inferior quality. This […]

Correcting Al Hamichya Mistakes

Correcting Al Hamichya Mistakes

By: Rabbi Mordechai Frankel

Kashrus Kurrents Winter 2014

Q:   When I say  Al Hamichya and make a mistake, I don’t know what to do.  Could you give me some guidelines?

A:    There are three places in the  brocha me’ein shalosh (colloquially known as  Al Hamichya) where the text changes, depending on what was eaten:

(1)    The  brocha starts with the words “ Boruch atah Hashem Elokeinu melech ha’olamal …”, followed by either “ hagefen  ve’al pri hagefen” if a person drank wine, “ ha’eitz  ve’al pri ha’eitz” if he ate fruit from the  shivas  haminim, “ hamichyeh  ve’al hakalkalah” if he ate food made from any of the five types of grain (wheat, barley, oats, rye, spelt), or a combination of these phrases if he ate or drank a combination of items.1

(2)    Further on in the  brocha , one says “…  ve’nodeh  lecha al ha’aretz ve’al …”, followed by either “ pri  hagofen”, “ ha’peyros”, “ hamichya”, or a combination of these phrases.

(3)    The  brocha concludes with the words “…  Boruch atah Hashem al …”, followed once again by either “ hagefen  ve’al pri hagefen”, […]

Does Using Early-Bird Discounts Create a Ribbis Issue?

Does Using Early-Bird Discounts Create a Ribbis Issue?

By: Rabbi Mordechai Frankel

Kashrus Kurrents Spring 2014

Q:        I would like to send my young children to a backyard camp during the summer.  The camp is offering an ‘early-bird special’ if I register my children now.  If I wait until the summer to register, they will charge more.  Is there any ribbis issue with registering now and receiving the discount?

A:         Ribbis involves lending money to another Jew and charging interest.  Doing so may violate a Torah prohibition or a rabbinic prohibition, depending upon the situation.  If it is necessary to charge interest, the two parties may sign a document known as a “heter iska”, which converts the loan into a business investment, thereby avoiding the prohibition of ribbis.1  People are often unaware that a number of common transactions may violate the prohibition of ribbis.  Here are a couple of examples:

(1)   Reuven buys an item with Shimon’s credit card, and assures Shimon that he will pay the credit card bill.  However, Reuven forgets to pay the bill on time, and […]

Separating Challah When Giving the Bread Away

Separating Challah When Giving the Bread Away

By: Rabbi Mordechai Frankel

Kashrus Kurrents Summer 2014

Q: I have heard that someone who bakes loaves of bread with the intention of giving them to other people does not separate challah with a brocha. Can you explain the parameters of this halacha?

A: One is obligated to perform the mitzvah of separating challah when kneading dough which will be baked into bread. The amount of flour one must knead in order to be obligated in this mitzvah is an asiris ha’aifa, which is equivalent to the volume of 43⅕ beitzah.1 The exact volume of a beitzah is a matter of dispute. L’halacha, one should separate challah without a brocha when kneading 2.6 lbs. of flour, which on average is equivalent to 8⅔ cups of flour. According to Rav Chaim Noeh, one can separate challah with a brocha when kneading 3.675 lbs. or more of flour (on average, 12¼ cups). Many follow the opinion of the […]

Security Cameras on Shabbos

Security Cameras on Shabbos

By: Rabbi Mordechai Frankel

Kashrus Kurrents Winter 2015

Q:   It has become common for businesses and stores to have security video cameras which monitor the foot traffic in front of their properties. Similarly, many apartment buildings have video cameras which record anything that enters or exits the building. Is a Jew allowed to walk in front of such a video camera on Shabbos? Can a Jew operate a video camera knowing that other Jews will walk in front of it on Shabbos?

A:    In order to answer this question, we need to address four issues.

(1)  The video camera may be connected to a monitor that displays the recorded image.  May a person walk in front of a video camera on  Shabbos if it will cause his image to be displayed on a monitor? 

One of the forbidden  melachos on  Shabbos is  kesiva, writing.  Drawing a picture is also considered to be  kesiva  mideoraissa (writing which is forbidden by the  Torah). 1However, […]

Eruv Chatzeiros in a Hotel on Shabbos

Eruv Chatzeiros in a Hotel on Shabbos

By: Rabbi Mordechai Frankel

Kashrus Kurrents Fall 2013

Q: When a person stays in a hotel for Shabbos, does he need to make an eruv chatzeiros to allow him to carry items in the hallways and lobby?

A: In order to answer this question, we need to review some of the basic halachos of eruv chatzeiros.

In the times of Chazal, it was common for private houses to be situated around the perimeter of a rectangular central courtyard, known as a chatzeir. The chatzeir was used by the members of these houses for chores, such as washing clothes and grinding grain. The Torah considers a chatzeir to be a reshus hayachid (a private domain) if it is surrounded on all sides by walls of the houses and one could, therefore, carry in the chatzeir on Shabbos. However, due to the fact that a chatzeir is less private than a house, the Rabonnon forbade carrying in a chatzeir […]

Sheva Brachos Guidelines

Sheva Brachos Guidelines

By: Rabbi Mordechai Frankel

Kashrus Kurrents Spring 2013

Q: Could you give me some guidelines as to when sheva brochos are recited?

A: When a chosson and kallah get married, sheva brochos are recited on three occasions: (i) under the chupah, (ii) at the end of the meal following the chupah, and (iii) at the end of subsequent meals that are made lekovod the chosson and kallah. It is this third category which is commonly known as sheva brochos. If the chosson and kallah have both been previously married, sheva brochos are recited only on the day of the wedding.1 If either the chosson or kallah has not been previously married, sheva brochos are recited on the seven days following the wedding, with the day of the wedding reckoned as the first of those seven days.2 If neither the chosson nor the kallah have previously been living an observant lifestyle (or if one of them has […]

Creating a Round Cake Decorated as a Sun | Doing Dental Work on a Parent

Creating a Round Cake Decorated as a Sun | Doing Dental Work on a Parent

By: Rabbi Mordechai Frankel

Kashrus Kurrents Summer 2008

Inaugural Issue: Shailos From The Institute Of Halacha
Kashrus Kurrents is proud to launch a new column, “Insights from the Institute”.  In this regular feature, Rabbi Mordechai Frankel will share with our readership intriguing shailos from his email inbox. The following is a sampling of the types of interesting questions that will be addressed in future columns.

Heating & Cooling – Using Ice from an Ice Maker on Shabbos | Using an Electric Hot Water Heater on Yom Tov

Heating & Cooling – Using Ice from an Ice Maker on Shabbos | Using an Electric Hot Water Heater on Yom Tov

By: Rabbi Mordechai Frankel

Kashrus Kurrents Winter 2008

Q: My freezer has an ice making machine, which has an arm that rises as ice is produced and lowers when ice is removed. I generally turn the machine off before Shabbos by lifting the arm until it is fully raised. If I forget to do this, can I remove ice on Shabbos from the ice maker?

A: There are various types of ice maker machines available, and they do not all work in the same way.  However, many of the commonly available models employ the following mechanism.  The ice making process begins when the ice maker signals the water valve to open, and a specified amount of […]

Maris Ayin When Entering Non-Kosher Venues

Maris Ayin When Entering Non-Kosher Venues

By: Rabbi Mordechai Frankel

Kashrus Kurrents Summer 2009

Q: May one enter a non‐kosher restaurant to get a drink of water, use the restroom or attend a business luncheon?  If a person does enter such an establishment, may he eat kosher items such as whole fruit?  May one buy a cup of coffee at a non‐kosher facility, such as a highway rest stop or Starbucks?

When Non-Mevushal Wine Becomes Stam Yeinom | Shipping Packages for Shabbos Delivery

When Non-Mevushal Wine Becomes Stam Yeinom | Shipping Packages for Shabbos Delivery

By: Rabbi Mordechai Frankel

Kashrus Kurrents Fall 2009

Q:       I had a bottle of wine stored in the shelving unit on the door of my refrigerator.  I was in the kitchen, and I saw my non-Jewish hired help open the refrigerator.   She knows that she is not allowed to touch my wine, but did not pay attention to the fact that opening the refrigerator moves the wine on the door.  Can I still drink the wine?

Using a Warming Tray on Shabbos

Using a Warming Tray on Shabbos

By: Rabbi Mordechai Frankel

Kashrus Kurrents Winter 2009

Q:       I would like to buy a warming tray that has been manufactured for the Shomer Shabbos community. It is a glass covered warming tray and has a variable temperature dial with a removable knob. It can be set at a minimum temperature of 110 0F and a maximum temperature of 230 0F. It has a sticker on it stating that it is intended solely for the reheating of cooked foods and is not intended to be used for cooking. How may this tray be used on Shabbos?

A:  In order to answer this question, one must have an understanding of the Rabbinic prohibitions of shehiyah and chazarah.  The parameters of these two prohibitions differ for Ashkenazim and Sefardim.  This response will explain the halachah as it applies to Ashkenazim.

Shehiyah:  Shehiyah is the act of placing food on an open flame before the onset of Shabbos […]

Eating in a Canvas Sukkah that Sways in the Wind

Eating in a Canvas Sukkah that Sways in the Wind

By: Rabbi Mordechai Frankel

Kashrus Kurrents Fall 2010

Q: I have been invited to eat out on Sukkos.  The sukkah has canvas walls which shake in the wind.  Is this a problem?

A: The Mishna1 states that a person can use the trunks of trees as a sukkah wall. This Mishna is referring to a scenario where the tree trunks are very close to one another, or the space between them has been filled with some other material, and the overhang of the tree branches will not invalidate the schach. The Gemara2 states that this is true only if the tree trunks do not sway.  If the tree trunks are supple and sway in a normal wind, the sukkah wall is not valid. The Shulchan Aruch3 codifies this halacha, and adds that if the tree trunks are supple one can tie them to each other in such […]

Using a CPAP Machine on Shabbos

Using a CPAP Machine on Shabbos

By: Rabbi Mordechai Frankel

Kashrus Kurrents Winter 2010

Q: My doctor has told me that I have sleep apnea, and advised me to use a sleep apnea machine.  Can this device be used on Shabbos?

A: Sleep apnea is a disorder characterized by abnormal pauses in breathing or instances of abnormally low breathing during sleep.  Obstructive sleep apnea, the most common form of the disorder, is caused by the relaxation of the walls of soft tissue in the airway of the throat during sleep.  Common symptoms include loud snoring, restless sleep, and daytime sleepiness.  Sleep-disordered breathing is associated with an increased risk of cardiovascular disease, stroke, high blood pressure,arrhythmias, diabetes, and sleep deprived driving accidents.1  Recent studies have shown that sleep apnea affects about 16% of men and 5% of women between 30 and 65 years of age.[...] Read More

Can a Kohain Visit a Science Museum

Can a Kohain Visit a Science Museum

By: Rabbi Mordechai Frankel

Kashrus Kurrents Summer 2011

Q: Can a Kohain enter the Maryland Science Center, located in downtown Baltimore?

Guidelines for Men’s Haircuts

Guidelines for Men’s Haircuts

By: Rabbi Mordechai Frankel

Kashrus Kurrents Spring 2012

Q: When my barber works on the area around my ear and temple, what I am allowed to let him do and what should I stop him from doing?

Which Materials May Be Kashered (and Which May Not)

Which Materials May Be Kashered (and Which May Not)

By: Rabbi Mordechai Frankel

Kashrus Kurrents Summer 2012

Q: I have a number of utensils which need kashering through hagalah (immersion in boiling water). Which materials may and may not be kashered?

A:   A fleishig utensil which comes into contact with hot milchig food or a milchig utensil which comes into contact with hot fleishig food needs to be kashered before further use.  There are a number of methods for kashering, dependent upon the manner of contact between the utensil and the food.  Perhaps the most common form of kashering is hagalah, in which the utensil is immersed in boiling water.

Metal
The Torah tells us that a vessel may be kashered if it is made from one of six metals:  gold, silver, copper, iron, tin or lead.1  There are other metals and alloys which were not in common use at the time of Matan […]