Author Archives: Rabbi Avrohom Mushell

The Plot Thickens: The Marvel of Collagen

By: Rabbi Avrohom Mushell

Summer 2025

From fruit-on-the-bottom yogurt cups to your Bubby’s famous galarita (a.k.a. p’tcha), collagen – and its modified form, gelatin – seems to be everywhere these days. It is no exaggeration to state that the food and health industries are currently undergoing a veritable collagen craze. In 2023, the collagen market had a value of $5.1 billion, with no signs of slowing down; it is projected to top $7.4 billion by 2030.[1] What exactly is collagen and why is it so popular?

Collagen is a fibrous, insoluble protein found in all living beings. The word collagen comes from the Greek word kolla, meaning glue, which is a fitting term for a substance that makes up a major portion of bone, skin and connective tissue and serves as the glue that holds the body together. There are three main types: type I, found in skin, tendons, bones and ligaments; type II, […]

Gelatin Substitutes

By: Rabbi Avrohom Mushell

Summer 2025

Widely available gelatin substitutes provide kosher consumers with sound alternatives to meat- and fish-based gelatin products. They are also making headway in the field of vitamin and medicinal capsules.

Popular gelatin alternatives that are seaweed-based include:

► Agar Agar/Kanten:Derived from some species of red algae. Has strong setting properties similar to gelatin. Will gel at room temperature. Is more affected by acidity than gelatin and thus can cause fruity desserts to turn watery.

►Carrageenan/Irish Moss: Is a reddish-purple seaweed. Less stiff than Agar Agar. Useful as an emulsifier and a thickener.

Gelatin alternatives that are vegetable-derived and that can be used as stabilizers, emulsifiers, or thickeners include:

► Gellan Gum: Produced by the microbial fermentation of a carbohydrate using the bacterium Sphingomonas elodea. Requires reliable kosher certification to verify that the ingredients used in their processing are all kosher and that the equipment used for their processing are all kosher parve.

► Guar Gum: A […]

Using an Oven on Shabbos and Yom Tov

By: Rabbi Avrohom Mushell

Reviewed March 2024

To download and print a handy summary of these halachos, click here.

Cooking in the modern kitchen is a whole new experience. Technological advances have taken the old stovetop and oven and upgraded them to be safer, more efficient, and “smart” for today’s lifestyle. They are also far more complicated. With these transformations, the observant Jew is faced with challenges that did not confront him in the past.

To understand how these changes affect the halachic use of ovens and cooktops on Shabbos and Yom Tov, it is worthwhile to review some laws and concepts as they relate to cooking on Shabbos and Yom Tov.

A. Terms and Prohibitions Pertaining to Food Preparation on Shabbos and Yom Tov

Definitions of Basic Terms

Melacha A melacha is a Torah prohibited act derived from the constructive acts performed in erecting the Mishkan . These forbidden acts are known […]

Oven Kashrus: For Yom Tov Use

By: Rabbi Avrohom Mushell

To download and print a handy UPDATED summary of the halachos regarding oven use on Yom Tov, click here.

Summer 2001

Yom Tov celebrations could never be complete without the traditional piping hot delicacies from past generations. However, the kosher homemaker must be well educated on how to prepare Yom Tov meals without fear of transgressing a Torah or rabbinic prohibition.

When mentioning the prohibition of work on Shabbos the Torah writes, “Do not do any melacha (work prohibited on Shabbos).”1 This prohibition applies to melacha performed for food preparation, as well as other non-food purposes. In stating the prohibition of melacha on Yom Tov the Torah writes, “You shall not do laborious work.”2

In addition, when giving the initial command about the Yom Tov of Pesach, the Torah writes, “No work may be done on them (first and seventh day of Pesach), except for what must be eaten for any […]

Getting Into the Thick of Things: GELATIN

By: Rabbi Avrohom Mushell

Published Spring 2013

Have you ever had a slice of p’tcha galarita – that spicy, globby stuff Bubby used to cook up? How did she manage to make it so thick?

Better yet, open a can of gefilte fish. Look at the stiff jell that comes as its broth. Why is it that when you cook your own gefilte fish, you do not get that solid jelly from your broth? Did you ever wonder why theirs is so thick and yours is not?

COLLAGEN may be the answer to this thickening question.

Collagen is a fibrous, insoluble protein that makes up a major portion of bone, skin and connective tissue. By cooking animal bones or adding fish bones to the broth of your gefilte fish, you will extract some of the collagen from the bones. This gives you the wobbly jelly in p’tcha or in the gefilte fish that comes in a can.

The most common form in which collagen is marketed is partially hydrolyzed state known commonly as gelatin. […]

Me’ein Olam Habah, Instant Style: Instant Foods in the Kosher Home

By: Rabbi Avrohom Mushell

August 2013

(Click here for a helpful Glossary of Terms used in this article.)

Our fast paced lifestyles have opened a market for easy to prepare and pre-cooked types of foods. Ready to eat, heat-and-serve or just add boiling water. Packaging labels proclaim that you can have that old fashioned home cooked flavor in only a fraction of the time. For the kosher consumer there are a variety of concerns that present themselves when using these quick to prepare concoctions. As can be expected, the less you have to do at home to prepare, the more that has been done at the factory to make the food edible. Therefore, one must be sure that the product has reliable kosher certification.

One must also be cautious as well when using these processed foods on Shabbos. As a rule, when dealing with raw foods, the Shabbos […]

Oven Kashrus: For Shabbos Use

By: Rabbi Avrohom Mushell

To download and print a handy UPDATED summary of these halachos, click here.

Winter 2005

Cookin’ just ain’t what it used to be. Technological advances have taken the old stovetop and oven and upgraded them to be safer, more efficient, and smart for today’s lifestyle. They are also far more complicated. With these transformations, the observant Jew is faced with challenges that did not confront him in the past.

To understand how these changes affect the halachic use of the stovetop on Shabbos and Yom Tov, it is worthwhile to review some laws and concepts as they relate to cooking on Shabbos and Yom Tov.

DEFINITION OF MELACHA

Cooking on Shabbos is a Torah prohibition derived from the constructive acts performed in erecting the mishkan. This forbidden act is known as a melacha. There are 39 categories of prohibited acts.

MELACHA OF COOKING

The prohibition of cooking on Shabbos is defined as the act of using […]

Keeping Your Cool: All About Refrigerators

By: Rabbi Avrohom Mushell

Winter 2003

Few of us can remember life in the kitchen without the help of a refrigerator. Probably the most used appliance in the home, the electric refrigerator was mass produced as a home appliance in the early 1920’s. Although many improvements and modifications have taken place over the years, the basic principles employed in the home refrigerator remain the same.

How Refrigeration Works

The natural laws of physics dictate that as a liquid evaporates into a gas, it absorbs heat from the surrounding areas. In turn, these surrounding areas become cold. (If you touch the cylinder supplying gas to a barbecue grill, you will notice the cylinder getting cold and icy because the liquid in the cylinder is rapidly changing to a gas as it leaves the cylinder to provide fuel for the flame.) Although we may view our refrigerator as […]