Butter

BUTTER IS A dairy product made from sweet cream—the thick layer skimmed off the top of milk. This heavy cream contains both butterfat and buttermilk; when churned, the butterfat bonds into solid butter while the buttermilk separates.

From a halachic perspective, butter differs from milk and cheese. Cholov akum—milk produced by a non-Jew—is prohibited because there is a concern that milk from a non-kosher animal may have been added. Gevinas akum—cheese produced by a non-Jew—is forbidden because cheese requires a curdling agent, traditionally rennet, which may have been derived from a neveila. Butter, however, historically involved neither concern: milk from a non-kosher species does not churn into butter, and the process requires no rennet or enzymes—only mechanical churning. Therefore, as long as any residual droplets of un-churned milk (which could theoretically be non-kosher) were removed, butter produced by a non-Jew was understood to be halachically permissible.

The Shulchan Oruch (Y”D 115:3) reflects this:

“Butter produced by a non-Jew: one should not protest against the people of a place who have the custom to permit it. But if the majority of the community treats it as forbidden, that custom may not be changed. In a place without an established custom, if the butter is cooked until the milk residues are removed, it is permitted.

Rema: It is permitted even lechatchila to cook it to remove the milk residues.”

For centuries, this was the accepted standard. Butter was an inherently kosher item—something even those careful to keep cholov Yisroel could purchase without supervision.

Today, this is no longer the case.

Modern food production has changed, and butter can no longer be treated as inherently kosher. Contemporary manufacturing introduces several kashrus concerns that did not exist in earlier eras. Those who keep cholov Yisroel must be particularly vigilant, and even those who do not, should only consume butter with a reliable hechsher.

The reasons fall into three major categories:

Manufacturers utilize every part of the raw material. Once companies learned that whey cream can be  mixed with sweet cream and churned into butter, cheese plants began selling their whey cream to butter manufacturers. This practice is widespread.

This creates two major kashrus concerns:

Cheese is produced using rennet, starter cultures, and sometimes flavor additives. If any of these  ingredients are non-kosher, the cheese is rendered non-kosher. The question is whether this status extends to the whey. Although the rennet used is far less than 1/60 of the mixture—normally enough to be botul—rennet is a davar ha-ma’amid, a substance essential to forming the product, and therefore not  subject to bittul. Cheese produced with non-kosher rennet is not kosher.

Rav Moshe Feinstein, zt”l, suggested that since rennet does not form the whey, the rennet is botul in the whey and the whey should remain kosher. Other Poskim disagreed, maintaining that once the cheese becomes non-kosher, its whey is likewise considered non-kosher.

In practice, most mainstream kashrus agencies—including the OK—do not permit whey from non-kosher
cheese.

Even when all the ingredients are kosher, cheese produced without Jewish involvement is prohibited as gevinas akum. Certain cheeses—Swiss cheese being the classic example—are cooked together with their whey at or above 120°F. During this heating process, the taste of gevinas akum transfers into  the whey, rendering the whey and its cream non-kosher.

However, not all Poskim agree with this. They argue that because the whey separates early in the cheese-making process, the status of gevinas akum has not yet taken effect at that stage. Accordingly, the whey does not absorb any prohibited taste and remains permissible. This position is not accepted in practice. The mainstream kashrus agencies treat such whey as non-kosher.

There is an additional concern with certain cheeses, such as mozzarella. After the cheese is fully formed, it is cooked in hot water—around 165°F—to make it malleable and give it the familiar “stretch” used for pizza. During this cooking process, the taste of gevinas akum is absorbed into the water. Many mozzarella manufacturers combine the cream from this water with whey cream and sell it to butter producers. Consequently, butter made with such whey cream is not kosher.

In conclusion, since whey cream can be blended with sweet cream to make butter, butter can no longer be assumed to be inherently kosher.

Many commercial butters today are not produced from pure churned cream alone. Manufacturers often add flavor components to intensify or standardize the buttery taste.

A common additive is starter distillate, a natural flavor made from steam-distilled cultured skim milk. These flavors can pose kashrus concerns, especially for those who keep cholov Yisroel, because they are most likely derived from milk that is not cholov Yisroel.

Other compounds in flavor systems may also require certification.

Therefore, butter containing starter distillate, added flavors, or “natural flavors” cannot be assumed to be inherently kosher.

Historically, butter was assumed to be kosher because milk from non-kosher species does not naturally churn into butter. This scientific reality formed the basis for treating butter as inherently kosher.

However, modern technology has evolved. Through specialized cultures and non-standard processing methods, it is now technically possible—though not simple or common—to produce butter from other types of milk, such as camel milk and other non-kosher sources. Once butter can be produced from any milk, even under specialized conditions, this assumption can no longer serve as a rule.

Given all the above, butter today should no longer be treated as a simple or inherently kosher product.  One should only purchase or consume butter with a reliable hechsher—especially those who are particular about cholov Yisroel.