Torah, Science & Kashrus in the Classroom

By: Rabbi Dovid Heber

Spring 2025

Over the years, I have been invited on multiple occasions to speak at various girls’ high schools in Lakewood about the impact of astronomy on the Jewish calendar and halachic zmanim. The inherent message I have aimed to give over is that one needs a basic understanding of math and science to fully comprehend certain halachic issues.

For example, the earth’s rotation on its axis is the basis of zmanei hayom (halachic times of the day) that are so much a part of our lives with regard to davening times and knowing when Shabbos and Yom Tov begin and end. One needs to know how the moon rotates around the earth to better understand Rosh Chodesh and the Jewish calendar. Indeed, Chazal had keen insights into scientific topics that were discovered hundreds of years later by researchers.

Investigating how a product is manufactured and analyzing the composition of the raw materials […]

Vinegar: Doing Kashrus Tastefully

By: Rabbi Tzvi Rosen

Spring 2025

Vinegar has a long and storied history and plays a highly-prized role in every aspect of modern life – whether as a nutrient, flavorant, preservative or household cleanser. The name vinegar is derived from the French “vin aigre, which literally means sour wine. According to legend, its discovery is credited to a neglected barrel of wine that had been left in storage and allowed to ferment and become sour.

We find several references to vinegar in both Tanach and the Gemara. A nazir is forbidden to consume anything derived from grapes, which includes wine vinegar;[1] Dovid Hamelech accuses his tormentors metaphorically of giving him vinegar to quench his thirst;[2] Boaz’s workers dip their bread in vinegar;[3] and Mar Ukva refers to himself as “Chometz ben Yayin” – Vinegar, the son of Wine – when comparing himself to his father’s degree of piety.[4]

Vinegar […]

Tevila Exemption for Appliances with Electronic Components

By: Rabbi Zvi Holland

Spring 2025

For many years, Rav Moshe Heinemann shlit”a instructed STAR-K to advise consumers that electric appliances which require tevila – such as toasters, waffle makers and hot water kettles – can be toveled and left to dry for three days. I have given this advice probably thousands of times and never once had a call back that the appliance was ruined.

There are, however, appliances that have both electric and electronic components. Electric devices convert electrical energy into other forms of energy, while electronic devices control the flow of electrons to perform tasks. Once exposed to water, damage to electronics begins within seconds – and the longer the exposure, the worse the damage.

Printed circuit boards consist of a laminate containing fiberglass and copper-clad epoxy, which forms the circuit’s wiring. This creates the perfect environment for galvanic or two-metal corrosion. Water contains minerals such as calcium, magnesium, potassium and salt, which accelerate […]

The Mitzvah of Tevilas Keilim

By: Rabbi Moshe Heinemann

Spring 2025

We are an Am Kadosh, a Holy People, who are mandated by Hashem to imbue all aspects of our lives with holiness. We elevate even the mundane activity of eating and vest it with special kedusha (sanctity): the food on our plates must be kosher and the table on which we eat is likened to the holy mizbe’ach. The plates themselves, and all keilim (vessels and utensils) used to prepare our food, must likewise be infused with kedusha.

Just as an aino Yehudi must tovel in a mikvah in order to become Jewish, so too must keilim acquired from an aino Yehudi undergo tevila in a mikvah before being used by a Jew. This is the mitzva of tevilas keilim.

If a kli requires tevila, it may not be used even once before it is toveled. If a kli was used numerous times without tevila, one is still required to immerse […]

Eretz Tzvi: Halachos of Visiting Eretz Yisroel

By: Rabbi Zvi Goldberg

Kashrus Kurrents Winter 2025 Issue | Updated February 2025

Eretz Yisroel is also called Eretz Tzvi. Chazal explain that, like the skin of a tzvi (a deer), which stretches beyond its natural state, the Land of Israel likewise expands to accommodate its inhabitants.[1] The Talmud states that anyone who walks four amos in Eretz Yisroel merits a place in the World to Come.[2] From here, some poskim derive that one fulfills a mitzvah merely by visiting Eretz Yisroel, even if one intends to stay for just a short while.[3]

Anyone planning a trip should be mindful of several pertinent halachos. We will review some of these below.

Scheduling the Flight

Do not plan to land too close to Shabbos; a flight landing on Friday morning is halachically acceptable.[4]

Try to avoid leaving Israel on a fast day, as the fast will be extended and you will not […]

The Mitzvah of Pidyon Haben: A Brief Overview

By: Rabbi Mordechai Frankel

Winter 2025

Mazel tov, you are the new parents of a baby boy! If the baby is the bechor of his mother – meaning that he is his mother’s first child – he will need to be redeemed by a kohen. The Torah tells us that Hashem slew every firstborn male in Mitzrayim, passing over the houses of the Bnei Yisrael. As a result, firstborn males acquired a measure of kedusha and must be redeemed by a kohen. The halachos of pidyon haben are somewhat complex and you may not have the time to familiarize yourself with them. Here, then, is a brief primer according to Ashkenazi custom.[1]

When Is a Pidyon Not Required?

If the baby is not his mother’s first child, even if he is his father’s first child

If the father is a kohen or levi, or if the mother is the daughter of a kohen or levi[...] Read More

Destination Simcha: From Meat Board to Surfboard

By: Rabbi Tzvi Rosen

Winter 2025

Forty years ago, the Lakeshore Hebrew Day School of New Orleans celebrated its 10th Anniversary Dinner in one of the premier hotels in the Vieux Carré, under the supervision of the local Orthodox rabbi. The day school then housed the New Orleans Kollel, of which I was a member. The event was so special that my Rosh Yeshiva, Rav Henoch Leibowitz ztz”l, was brought in as the guest speaker.

Before the event, we met extensively with the hotel chef, the pastry chef, and the food and beverage director to ensure that – even though the hotel was kosher certified – there would be no kashrus hiccups. When the big day arrived, I came with a crew made up of the chevrei hakollel to supervise the cooking for the event. Imagine our alarm when the chef showed us the “kosher” soup kettle – gleaming on the inside but encrusted with crawfish […]

The Perils of Partnering with a Party Planner

By: Rabbi Sholom Tendler

Winter 2025

[Sidebar to “Destination Simcha: From Meat Board to Surfboard.”]

For many people, juggling and coordinating all the details involved in planning a simcha – from booking the hall, arranging the décor, designing the invitations, planning the menu, ordering the food, to running random errands – is simply … overwhelming. Enter the party planner. This increasingly popular option has been gaining traction over the last few years, but not without its perils.

Party planners offer concierge services to help alleviate much of the stress involved in planning a simcha. They are typically more affordable than a full-service caterer who is under a hashgacha. Party planners work within your budget to offer any number of services at different tiers: they may handle the décor and design but may leave it to you to bring in your own food, or they can coordinate everything from “soup to nuts.” This is when the problems […]