Are Styrofoam Cups Kosher?

Are Styrofoam Cups Treif?

Environmentalists may seem to have the monopoly on decrying the use of Styrofoam (expanded polystyrene foam) products, but poskim debate the issue, too. Many Styrofoam cups are lubricated with a chemical substance that contains zinc stearate, which is derived from tallow (animal fat), a non-kosher product. This raises the question whether Styrofoam cups may be used for hot liquids, since, according to halachah, hot food is generally said to absorb the properties of the receptacle it’s in.

However, the consensus among poskim is that it’s permissible to use Styrofoam cups, and in fact there are no grounds for being machmir (stringent). Even though some of the reasons for permitting their use might not suffice on their own, the combination of the following factors determines the cups’ kosher status: 

Due to the high temperature of the purification process, the tallow is, in effect, denatured (the characteristic properties are destroyed, thereby removing it from the category of food).

The non-kosher food element is not b’ein (visible), and the quantity of the non-kosher ingredient present in the cup is so negligible that it’s batel (halachically nullified and considered as if it doesn’t exist).

Similarly, when using the cup, there is no problem of ein mvatlin issur l’chatchillah (deliberately overwhelming something treif with a large quantity of kosher ingredients in order to nullify it), which is generally not permissible; this is considered a case of ein kavanaso l’vatel (the intention is not to nullify it). 

Zeh v’zeh gorem: When something is by necessity a product of both permitted and forbidden ingredients, there is room to permit it under certain circumstances (the details of which necessitate a separate discussion). The lubricant in this case can only be produced through a combination of various ingredients, kosher and non kosher. 

It’s possible that it’s nosen ta’am lifgam (the taste added by the non-kosher ingredient is actually detrimental to the taste of the contents).

It’s not ben yomo (within 24 hours of the cup becoming treif), and therefore the remaining taste absorbed within the cup can no longer affect the taste of the drink in a positive way.

The fact that these cups are disposable and generally used only once is also grounds for leniency, for various reasons.

Since the cups are hardly used as a kli rishon (a vessel placed directly on the fire), only for irui mikli rishon (the liquid is poured into the cup from the urn), the amount of non- kosher ingredients in the cup is of little concern.

Due to these factors, and others, poskim are in agreement that it‘s perfectly acceptable to use Styrofoam cups for hot food. #458

https://halacha2go.com?number=458

Practical Halacha: One minute a day. By Horav Yosef Yeshaya Braun, shlita, Mara D'asra and member of the Badatz of Crown Heights.